[Mlir-commits] [mlir] [mlir][EmitC] Model lvalues as a type in EmitC (PR #91475)

Simon Camphausen llvmlistbot at llvm.org
Thu Jun 13 09:09:49 PDT 2024


https://github.com/simon-camp updated https://github.com/llvm/llvm-project/pull/91475

>From 7f109ca723083ffa2756060b86b9de78b34effbc Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 4 Jun 2024 11:55:43 +0000
Subject: [PATCH 01/13] Add lvalue type

---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td   |  41 +++++--
 .../mlir/Dialect/EmitC/IR/EmitCTypes.td       |  18 +++
 .../MemRefToEmitC/MemRefToEmitC.cpp           |   7 +-
 mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp |  33 +++++-
 mlir/lib/Dialect/EmitC/IR/EmitC.cpp           | 105 +++++++++++++----
 .../EmitC/Transforms/FormExpressions.cpp      |   3 +-
 mlir/lib/Target/Cpp/TranslateToCpp.cpp        |  21 +++-
 .../MemRefToEmitC/memref-to-emitc.mlir        |  24 ++--
 mlir/test/Conversion/SCFToEmitC/for.mlir      |  46 ++++----
 mlir/test/Conversion/SCFToEmitC/if.mlir       |  22 ++--
 mlir/test/Dialect/EmitC/invalid_ops.mlir      |  61 +++++-----
 mlir/test/Dialect/EmitC/invalid_types.mlir    |  66 ++++++++---
 mlir/test/Dialect/EmitC/ops.mlir              |  21 ++--
 mlir/test/Dialect/EmitC/transforms.mlir       |  48 ++------
 mlir/test/Dialect/EmitC/types.mlir            |  19 +++-
 mlir/test/Target/Cpp/common-cpp.mlir          |  17 ++-
 mlir/test/Target/Cpp/expressions.mlir         |  84 ++++++++------
 mlir/test/Target/Cpp/for.mlir                 |  82 ++++++++++----
 mlir/test/Target/Cpp/global.mlir              |  96 +++++++++++++---
 mlir/test/Target/Cpp/if.mlir                  |  12 +-
 mlir/test/Target/Cpp/invalid.mlir             |   2 +-
 mlir/test/Target/Cpp/lvalue.mlir              |  17 +++
 mlir/test/Target/Cpp/subscript.mlir           | 106 +++++++++++++-----
 mlir/test/Target/Cpp/variable.mlir            |  16 +--
 24 files changed, 665 insertions(+), 302 deletions(-)
 create mode 100644 mlir/test/Target/Cpp/lvalue.mlir

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index 5da8593f59563..30a626a49a869 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -97,7 +97,7 @@ def EmitC_ApplyOp : EmitC_Op<"apply", [CExpression]> {
   }];
   let arguments = (ins
     Arg<StrAttr, "the operator to apply">:$applicableOperator,
-    EmitCType:$operand
+    AnyTypeOf<[EmitCType, EmitC_LValueType]>:$operand
   );
   let results = (outs EmitCType:$result);
   let assemblyFormat = [{
@@ -835,6 +835,20 @@ def EmitC_LogicalOrOp : EmitC_BinaryOp<"logical_or", [CExpression]> {
   let assemblyFormat = "operands attr-dict `:` type(operands)";
 }
 
+def EmitC_LValueLoadOp : EmitC_Op<"lvalue_load", [
+  TypesMatchWith<"result type matches value type of 'operand'",
+                  "operand", "result",
+                  "::llvm::cast<LValueType>($_self).getValue()">
+]> {
+  let summary = "load an lvalue by assigning it to a local variable";
+  let description = [{}];
+
+  let arguments = (ins EmitC_LValueType:$operand);
+  let results = (outs AnyType:$result);
+
+  let assemblyFormat = "$operand attr-dict `:` type($operand)"; 
+}
+
 def EmitC_MulOp : EmitC_BinaryOp<"mul", [CExpression]> {
   let summary = "Multiplication operation";
   let description = [{
@@ -1009,7 +1023,7 @@ def EmitC_VariableOp : EmitC_Op<"variable", []> {
   }];
 
   let arguments = (ins EmitC_OpaqueOrTypedAttr:$value);
-  let results = (outs EmitCType);
+  let results = (outs AnyTypeOf<[EmitC_ArrayType, EmitC_LValueType]>);
 
   let hasVerifier = 1;
 }
@@ -1079,7 +1093,7 @@ def EmitC_GetGlobalOp : EmitC_Op<"get_global",
   }];
 
   let arguments = (ins FlatSymbolRefAttr:$name);
-  let results = (outs EmitCType:$result);
+  let results = (outs AnyTypeOf<[EmitC_ArrayType, EmitC_LValueType]>:$result);
   let assemblyFormat = "$name `:` type($result) attr-dict";
 }
 
@@ -1137,7 +1151,7 @@ def EmitC_AssignOp : EmitC_Op<"assign", []> {
     ```
   }];
 
-  let arguments = (ins EmitCType:$var, EmitCType:$value);
+  let arguments = (ins EmitC_LValueType:$var, EmitCType:$value);
   let results = (outs);
 
   let hasVerifier = 1;
@@ -1243,15 +1257,26 @@ def EmitC_SubscriptOp : EmitC_Op<"subscript", []> {
       EmitC_PointerType]>,
     "the value to subscript">:$value,
     Variadic<EmitCType>:$indices);
-  let results = (outs EmitCType:$result);
+  let results = (outs EmitC_LValueType:$result);
 
   let builders = [
     OpBuilder<(ins "TypedValue<ArrayType>":$array, "ValueRange":$indices), [{
-      build($_builder, $_state, array.getType().getElementType(), array, indices);
+      build(
+        $_builder,
+        $_state,
+        emitc::LValueType::get(array.getType().getElementType()),
+        array,
+        indices
+      );
     }]>,
     OpBuilder<(ins "TypedValue<PointerType>":$pointer, "Value":$index), [{
-      build($_builder, $_state, pointer.getType().getPointee(), pointer,
-            ValueRange{index});
+      build(
+        $_builder,
+        $_state,
+        emitc::LValueType::get(pointer.getType().getPointee()),
+        pointer,
+        ValueRange{index}
+      );
     }]>
   ];
 
diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
index 444395b915e25..fc795962a3e5b 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
@@ -83,6 +83,23 @@ def EmitC_ArrayType : EmitC_Type<"Array", "array", [ShapedTypeInterface]> {
   let hasCustomAssemblyFormat = 1;
 }
 
+def EmitC_LValueType : EmitC_Type<"LValue", "lvalue"> {
+  let summary = "EmitC lvalue type";
+
+  let description = [{
+    Values of this type can be assigned to and their address can be taken.
+  }];
+
+  let parameters = (ins "Type":$value);
+  let builders = [
+    TypeBuilderWithInferredContext<(ins "Type":$value), [{
+      return $_get(value.getContext(), value);
+    }]>
+  ];
+  let assemblyFormat = "`<` qualified($value) `>`";
+  let genVerifyDecl = 1;
+}
+
 def EmitC_OpaqueType : EmitC_Type<"Opaque", "opaque"> {
   let summary = "EmitC opaque type";
 
@@ -128,6 +145,7 @@ def EmitC_PointerType : EmitC_Type<"Pointer", "ptr"> {
     }]>
   ];
   let assemblyFormat = "`<` qualified($pointee) `>`";
+  let genVerifyDecl = 1;
 }
 
 #endif // MLIR_DIALECT_EMITC_IR_EMITCTYPES
diff --git a/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp b/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
index e0c421741b305..2e8fbbad14d40 100644
--- a/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
+++ b/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
@@ -137,12 +137,7 @@ struct ConvertLoad final : public OpConversionPattern<memref::LoadOp> {
     auto subscript = rewriter.create<emitc::SubscriptOp>(
         op.getLoc(), arrayValue, operands.getIndices());
 
-    auto noInit = emitc::OpaqueAttr::get(getContext(), "");
-    auto var =
-        rewriter.create<emitc::VariableOp>(op.getLoc(), resultTy, noInit);
-
-    rewriter.create<emitc::AssignOp>(op.getLoc(), var, subscript);
-    rewriter.replaceOp(op, var);
+    rewriter.replaceOpWithNewOp<emitc::LValueLoadOp>(op, resultTy, subscript);
     return success();
   }
 };
diff --git a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
index 0a89242225255..554d9d79f1700 100644
--- a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
+++ b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
@@ -63,9 +63,10 @@ static SmallVector<Value> createVariablesForResults(T op,
 
   for (OpResult result : op.getResults()) {
     Type resultType = result.getType();
+    Type varType = emitc::LValueType::get(resultType);
     emitc::OpaqueAttr noInit = emitc::OpaqueAttr::get(context, "");
     emitc::VariableOp var =
-        rewriter.create<emitc::VariableOp>(loc, resultType, noInit);
+        rewriter.create<emitc::VariableOp>(loc, varType, noInit);
     resultVariables.push_back(var);
   }
 
@@ -80,6 +81,14 @@ static void assignValues(ValueRange values, SmallVector<Value> &variables,
     rewriter.create<emitc::AssignOp>(loc, var, value);
 }
 
+SmallVector<Value> loadValues(const SmallVector<Value> &variables,
+                              PatternRewriter &rewriter, Location loc) {
+  return llvm::map_to_vector<>(variables, [&](Value var) {
+    Type type = cast<emitc::LValueType>(var.getType()).getValue();
+    return rewriter.create<emitc::LValueLoadOp>(loc, type, var).getResult();
+  });
+}
+
 static void lowerYield(SmallVector<Value> &resultVariables,
                        PatternRewriter &rewriter, scf::YieldOp yield) {
   Location loc = yield.getLoc();
@@ -113,15 +122,26 @@ LogicalResult ForLowering::matchAndRewrite(ForOp forOp,
   // Erase the auto-generated terminator for the lowered for op.
   rewriter.eraseOp(loweredBody->getTerminator());
 
+  IRRewriter::InsertPoint ip = rewriter.saveInsertionPoint();
+  rewriter.setInsertionPointToEnd(loweredBody);
+
+  SmallVector<Value> iterArgsValues =
+      loadValues(resultVariables, rewriter, loc);
+
+  rewriter.restoreInsertionPoint(ip);
+
   SmallVector<Value> replacingValues;
   replacingValues.push_back(loweredFor.getInductionVar());
-  replacingValues.append(resultVariables.begin(), resultVariables.end());
+  replacingValues.append(iterArgsValues.begin(), iterArgsValues.end());
 
   rewriter.mergeBlocks(forOp.getBody(), loweredBody, replacingValues);
   lowerYield(resultVariables, rewriter,
              cast<scf::YieldOp>(loweredBody->getTerminator()));
 
-  rewriter.replaceOp(forOp, resultVariables);
+  // Copy iterArgs into results after the for loop.
+  SmallVector<Value> resultValues = loadValues(resultVariables, rewriter, loc);
+
+  rewriter.replaceOp(forOp, resultValues);
   return success();
 }
 
@@ -173,7 +193,10 @@ LogicalResult IfLowering::matchAndRewrite(IfOp ifOp,
     lowerRegion(elseRegion, loweredElseRegion);
   }
 
-  rewriter.replaceOp(ifOp, resultVariables);
+  rewriter.setInsertionPointAfter(ifOp);
+  SmallVector<Value> results = loadValues(resultVariables, rewriter, loc);
+
+  rewriter.replaceOp(ifOp, results);
   return success();
 }
 
@@ -193,4 +216,4 @@ void SCFToEmitCPass::runOnOperation() {
   if (failed(
           applyPartialConversion(getOperation(), target, std::move(patterns))))
     signalPassFailure();
-}
+}
\ No newline at end of file
diff --git a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
index 20f47574b25ad..90fca1c2bb0b2 100644
--- a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
+++ b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
@@ -61,6 +61,9 @@ void mlir::emitc::buildTerminatedBody(OpBuilder &builder, Location loc) {
 bool mlir::emitc::isSupportedEmitCType(Type type) {
   if (llvm::isa<emitc::OpaqueType>(type))
     return true;
+  if (auto lType = llvm::dyn_cast<emitc::LValueType>(type))
+    // lvalue types are only allowed in a few places.
+    return false;
   if (auto ptrType = llvm::dyn_cast<emitc::PointerType>(type))
     return isSupportedEmitCType(ptrType.getPointee());
   if (auto arrayType = llvm::dyn_cast<emitc::ArrayType>(type)) {
@@ -140,6 +143,8 @@ static LogicalResult verifyInitializationAttribute(Operation *op,
            << "string attributes are not supported, use #emitc.opaque instead";
 
   Type resultType = op->getResult(0).getType();
+  if (auto lType = dyn_cast<LValueType>(resultType))
+    resultType = lType.getValue();
   Type attrType = cast<TypedAttr>(value).getType();
 
   if (resultType != attrType)
@@ -188,9 +193,17 @@ LogicalResult ApplyOp::verify() {
   if (applicableOperatorStr != "&" && applicableOperatorStr != "*")
     return emitOpError("applicable operator is illegal");
 
-  Operation *op = getOperand().getDefiningOp();
-  if (op && dyn_cast<ConstantOp>(op))
-    return emitOpError("cannot apply to constant");
+  Type operandType = getOperand().getType();
+  Type resultType = getResult().getType();
+  if (applicableOperatorStr == "&") {
+    if (!llvm::isa<emitc::LValueType>(operandType))
+      return emitOpError("operand type must be an lvalue when applying `&`");
+    if (!llvm::isa<emitc::PointerType>(resultType))
+      return emitOpError("result type must be a pointer when applying `&`");
+  } else {
+    if (!llvm::isa<emitc::PointerType>(operandType))
+      return emitOpError("operand type must be a pointer when applying `*`");
+  }
 
   return success();
 }
@@ -202,20 +215,18 @@ LogicalResult ApplyOp::verify() {
 /// The assign op requires that the assigned value's type matches the
 /// assigned-to variable type.
 LogicalResult emitc::AssignOp::verify() {
-  Value variable = getVar();
-  Operation *variableDef = variable.getDefiningOp();
-  if (!variableDef ||
-      !llvm::isa<emitc::VariableOp, emitc::SubscriptOp>(variableDef))
-    return emitOpError() << "requires first operand (" << variable
-                         << ") to be a Variable or subscript";
-
-  Value value = getValue();
-  if (variable.getType() != value.getType())
-    return emitOpError() << "requires value's type (" << value.getType()
-                         << ") to match variable's type (" << variable.getType()
-                         << ")";
-  if (isa<ArrayType>(variable.getType()))
-    return emitOpError() << "cannot assign to array type";
+  TypedValue<emitc::LValueType> variable = getVar();
+
+  if (!variable.getDefiningOp())
+    return emitOpError() << "cannot assign to block argument";
+
+  Type valueType = getValue().getType();
+  Type variableType = variable.getType().getValue();
+  if (variableType != valueType)
+    return emitOpError() << "requires value's type (" << valueType
+                         << ") to match variable's type (" << variableType
+                         << ")\n  variable: " << variable
+                         << "\n  value: " << getValue() << "\n";
   return success();
 }
 
@@ -842,9 +853,10 @@ LogicalResult emitc::SubscriptOp::verify() {
     }
     // Check element type.
     Type elementType = arrayType.getElementType();
-    if (elementType != getType()) {
+    Type resultType = getType().getValue();
+    if (elementType != resultType) {
       return emitOpError() << "on array operand requires element type ("
-                           << elementType << ") and result type (" << getType()
+                           << elementType << ") and result type (" << resultType
                            << ") to match";
     }
     return success();
@@ -868,9 +880,10 @@ LogicalResult emitc::SubscriptOp::verify() {
     }
     // Check pointee type.
     Type pointeeType = pointerType.getPointee();
-    if (pointeeType != getType()) {
+    Type resultType = getType().getValue();
+    if (pointeeType != resultType) {
       return emitOpError() << "on pointer operand requires pointee type ("
-                           << pointeeType << ") and result type (" << getType()
+                           << pointeeType << ") and result type (" << resultType
                            << ") to match";
     }
     return success();
@@ -964,6 +977,25 @@ emitc::ArrayType::cloneWith(std::optional<ArrayRef<int64_t>> shape,
   return emitc::ArrayType::get(*shape, elementType);
 }
 
+//===----------------------------------------------------------------------===//
+// LValueType
+//===----------------------------------------------------------------------===//
+
+LogicalResult mlir::emitc::LValueType::verify(
+    llvm::function_ref<mlir::InFlightDiagnostic()> emitError,
+    mlir::Type value) {
+  // Check that the wrapped type is valid. This especially forbids nested lvalue
+  // types.
+  if (!isSupportedEmitCType(value))
+    return emitError()
+           << "!emitc.lvalue must wrap supported emitc type, but got " << value;
+
+  if (llvm::isa<emitc::ArrayType>(value))
+    return emitError() << "!emitc.lvalue cannot wrap !emitc.array type";
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // OpaqueType
 //===----------------------------------------------------------------------===//
@@ -981,6 +1013,18 @@ LogicalResult mlir::emitc::OpaqueType::verify(
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// PointerType
+//===----------------------------------------------------------------------===//
+
+LogicalResult mlir::emitc::PointerType::verify(
+    llvm::function_ref<mlir::InFlightDiagnostic()> emitError, Type value) {
+  if (llvm::isa<emitc::LValueType>(value))
+    return emitError() << "pointers to lvalues are not allowed";
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // GlobalOp
 //===----------------------------------------------------------------------===//
@@ -1078,9 +1122,22 @@ GetGlobalOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
            << getName() << "' does not reference a valid emitc.global";
 
   Type resultType = getResult().getType();
-  if (global.getType() != resultType)
-    return emitOpError("result type ")
-           << resultType << " does not match type " << global.getType()
+  Type globalType = global.getType();
+
+  // global has array type
+  if (llvm::isa<ArrayType>(globalType)) {
+    if (globalType != resultType)
+      return emitOpError("on array type expects result type ")
+             << resultType << " to match type " << globalType
+             << " of the global @" << getName();
+    return success();
+  }
+
+  // global has non-array type
+  auto lvalueType = dyn_cast<LValueType>(resultType);
+  if (!lvalueType || lvalueType.getValue() != globalType)
+    return emitOpError("on non-array type expects result inner type ")
+           << lvalueType.getValue() << " to match type " << globalType
            << " of the global @" << getName();
   return success();
 }
diff --git a/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp b/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
index 82bd031430d36..758b8527c2fa5 100644
--- a/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
+++ b/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
@@ -38,7 +38,8 @@ struct FormExpressionsPass
     auto matchFun = [&](Operation *op) {
       if (op->hasTrait<OpTrait::emitc::CExpression>() &&
           !op->getParentOfType<emitc::ExpressionOp>() &&
-          op->getNumResults() == 1)
+          op->getNumResults() == 1 &&
+          isSupportedEmitCType(op->getResult(0).getType()))
         createExpression(op, builder);
     };
     rootOp->walk(matchFun);
diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index 202df89025f26..66808289e79f7 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -298,7 +298,7 @@ static bool shouldBeInlined(ExpressionOp expressionOp) {
   // Do not inline expressions used by subscript operations, since the
   // way the subscript operation translation is implemented requires that
   // variables be materialized.
-  if (isa<emitc::SubscriptOp>(user))
+  if (isa<emitc::SubscriptOp, emitc::GetGlobalOp>(user))
     return false;
 
   // Do not inline expressions used by ops with the CExpression trait. If this
@@ -377,6 +377,14 @@ static LogicalResult printOperation(CppEmitter &emitter,
   return success();
 }
 
+static LogicalResult printOperation(CppEmitter &emitter,
+                                    emitc::LValueLoadOp lValueLoadOp) {
+  if (failed(emitter.emitAssignPrefix(*lValueLoadOp)))
+    return failure();
+
+  return emitter.emitOperand(lValueLoadOp.getOperand());
+}
+
 static LogicalResult printOperation(CppEmitter &emitter,
                                     emitc::SubscriptOp subscriptOp) {
   // Add name to cache so that `hasValueInScope` works.
@@ -1399,7 +1407,7 @@ LogicalResult CppEmitter::emitVariableAssignment(OpResult result) {
 
 LogicalResult CppEmitter::emitVariableDeclaration(OpResult result,
                                                   bool trailingSemicolon) {
-  if (isa<emitc::SubscriptOp>(result.getDefiningOp()))
+  if (isa<emitc::SubscriptOp, emitc::GetGlobalOp>(result.getDefiningOp()))
     return success();
   if (hasValueInScope(result)) {
     return result.getDefiningOp()->emitError(
@@ -1500,9 +1508,10 @@ LogicalResult CppEmitter::emitOperation(Operation &op, bool trailingSemicolon) {
                 emitc::DivOp, emitc::ExpressionOp, emitc::ForOp, emitc::FuncOp,
                 emitc::GlobalOp, emitc::GetGlobalOp, emitc::IfOp,
                 emitc::IncludeOp, emitc::LogicalAndOp, emitc::LogicalNotOp,
-                emitc::LogicalOrOp, emitc::MulOp, emitc::RemOp, emitc::ReturnOp,
-                emitc::SubOp, emitc::SubscriptOp, emitc::UnaryMinusOp,
-                emitc::UnaryPlusOp, emitc::VariableOp, emitc::VerbatimOp>(
+                emitc::LogicalOrOp, emitc::LValueLoadOp, emitc::MulOp,
+                emitc::RemOp, emitc::ReturnOp, emitc::SubOp, emitc::SubscriptOp,
+                emitc::UnaryMinusOp, emitc::UnaryPlusOp, emitc::VariableOp,
+                emitc::VerbatimOp>(
               [&](auto op) { return printOperation(*this, op); })
           // Func ops.
           .Case<func::CallOp, func::FuncOp, func::ReturnOp>(
@@ -1605,6 +1614,8 @@ LogicalResult CppEmitter::emitType(Location loc, Type type) {
       os << "[" << dim << "]";
     return success();
   }
+  if (auto lType = dyn_cast<emitc::LValueType>(type))
+    return emitType(loc, lType.getValue());
   if (auto pType = dyn_cast<emitc::PointerType>(type)) {
     if (isa<ArrayType>(pType.getPointee()))
       return emitError(loc, "cannot emit pointer to array type ") << type;
diff --git a/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir b/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
index bc40ef48268eb..15ffd815250d2 100644
--- a/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
+++ b/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
@@ -3,11 +3,11 @@
 // CHECK-LABEL: memref_store
 // CHECK-SAME:  %[[v:.*]]: f32, %[[i:.*]]: index, %[[j:.*]]: index
 func.func @memref_store(%v : f32, %i: index, %j: index) {
-  // CHECK: %[[ALLOCA:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.array<4x8xf32>
+  // CHECK-NEXT: %[[ALLOCA:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.array<4x8xf32>
   %0 = memref.alloca() : memref<4x8xf32>
 
-  // CHECK: %[[SUBSCRIPT:.*]] = emitc.subscript %[[ALLOCA]][%[[i]], %[[j]]] : (!emitc.array<4x8xf32>, index, index) -> f32
-  // CHECK: emitc.assign %[[v]] : f32 to %[[SUBSCRIPT:.*]] : f32
+  // CHECK-NEXT: %[[SUBSCRIPT:.*]] = emitc.subscript %[[ALLOCA]][%[[i]], %[[j]]] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<f32>
+  // CHECK-NEXT: emitc.assign %[[v]] : f32 to %[[SUBSCRIPT]] : <f32>
   memref.store %v, %0[%i, %j] : memref<4x8xf32>
   return
 }
@@ -17,14 +17,13 @@ func.func @memref_store(%v : f32, %i: index, %j: index) {
 // CHECK-LABEL: memref_load
 // CHECK-SAME:  %[[i:.*]]: index, %[[j:.*]]: index
 func.func @memref_load(%i: index, %j: index) -> f32 {
-  // CHECK: %[[ALLOCA:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.array<4x8xf32>
+  // CHECK-NEXT: %[[ALLOCA:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.array<4x8xf32>
   %0 = memref.alloca() : memref<4x8xf32>
 
-  // CHECK: %[[LOAD:.*]] = emitc.subscript %[[ALLOCA]][%[[i]], %[[j]]] : (!emitc.array<4x8xf32>, index, index) -> f32
-  // CHECK: %[[VAR:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-  // CHECK: emitc.assign %[[LOAD]] : f32 to %[[VAR]] : f32
+  // CHECK-NEXT: %[[SUBSCRIPT:.*]] = emitc.subscript %[[ALLOCA]][%[[i]], %[[j]]] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<f32>
+  // CHECK-NEXT: %[[LOAD:.*]] = emitc.lvalue_load %[[SUBSCRIPT]] : <f32>
   %1 = memref.load %0[%i, %j] : memref<4x8xf32>
-  // CHECK: return %[[VAR]] : f32
+  // CHECK-NEXT: return %[[LOAD]] : f32
   return %1 : f32
 }
 
@@ -33,14 +32,15 @@ func.func @memref_load(%i: index, %j: index) -> f32 {
 // CHECK-LABEL: globals
 module @globals {
   memref.global "private" constant @internal_global : memref<3x7xf32> = dense<4.0>
-  // CHECK: emitc.global static const @internal_global : !emitc.array<3x7xf32> = dense<4.000000e+00>
+  // CHECK-NEXT: emitc.global static const @internal_global : !emitc.array<3x7xf32> = dense<4.000000e+00>
   memref.global @public_global : memref<3x7xf32>
-  // CHECK: emitc.global extern @public_global : !emitc.array<3x7xf32>
+  // CHECK-NEXT: emitc.global extern @public_global : !emitc.array<3x7xf32>
   memref.global @uninitialized_global : memref<3x7xf32> = uninitialized
-  // CHECK: emitc.global extern @uninitialized_global : !emitc.array<3x7xf32>
+  // CHECK-NEXT: emitc.global extern @uninitialized_global : !emitc.array<3x7xf32>
 
+  // CHECK-LABEL: use_global
   func.func @use_global() {
-    // CHECK: emitc.get_global @public_global : !emitc.array<3x7xf32>
+    // CHECK-NEXT: emitc.get_global @public_global : !emitc.array<3x7xf32>
     %0 = memref.get_global @public_global : memref<3x7xf32>
     return
   }
diff --git a/mlir/test/Conversion/SCFToEmitC/for.mlir b/mlir/test/Conversion/SCFToEmitC/for.mlir
index 7e59eac3d4095..32a9dfce7f4e6 100644
--- a/mlir/test/Conversion/SCFToEmitC/for.mlir
+++ b/mlir/test/Conversion/SCFToEmitC/for.mlir
@@ -47,16 +47,20 @@ func.func @for_yield(%arg0 : index, %arg1 : index, %arg2 : index) -> (f32, f32)
 // CHECK-SAME:      %[[VAL_0:.*]]: index, %[[VAL_1:.*]]: index, %[[VAL_2:.*]]: index) -> (f32, f32) {
 // CHECK-NEXT:    %[[VAL_3:.*]] = arith.constant 0.000000e+00 : f32
 // CHECK-NEXT:    %[[VAL_4:.*]] = arith.constant 1.000000e+00 : f32
-// CHECK-NEXT:    %[[VAL_5:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-// CHECK-NEXT:    %[[VAL_6:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-// CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_5]] : f32
-// CHECK-NEXT:    emitc.assign %[[VAL_4]] : f32 to %[[VAL_6]] : f32
-// CHECK-NEXT:    emitc.for %[[VAL_9:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:      %[[VAL_10:.*]] = arith.addf %[[VAL_5]], %[[VAL_6]] : f32
-// CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_5]] : f32
-// CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_6]] : f32
+// CHECK-NEXT:    %[[VAL_5:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+// CHECK-NEXT:    %[[VAL_6:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+// CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_5]] : <f32>
+// CHECK-NEXT:    emitc.assign %[[VAL_4]] : f32 to %[[VAL_6]] : <f32>
+// CHECK-NEXT:    emitc.for %[[VAL_7:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
+// CHECK-NEXT:      %[[VAL_8:.*]] = emitc.lvalue_load %[[VAL_5]] : <f32>
+// CHECK-NEXT:      %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_6]] : <f32>
+// CHECK-NEXT:      %[[VAL_10:.*]] = arith.addf %[[VAL_8]], %[[VAL_9]] : f32
+// CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_5]] : <f32>
+// CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_6]] : <f32>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    return %[[VAL_5]], %[[VAL_6]] : f32, f32
+// CHECK-NEXT:    %[[VAL_11:.*]] = emitc.lvalue_load %[[VAL_5]] : <f32>
+// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.lvalue_load %[[VAL_6]] : <f32>
+// CHECK-NEXT:    return %[[VAL_11]], %[[VAL_12]] : f32, f32
 // CHECK-NEXT:  }
 
 func.func @nested_for_yield(%arg0 : index, %arg1 : index, %arg2 : index) -> f32 {
@@ -73,16 +77,20 @@ func.func @nested_for_yield(%arg0 : index, %arg1 : index, %arg2 : index) -> f32
 // CHECK-LABEL: func.func @nested_for_yield(
 // CHECK-SAME:      %[[VAL_0:.*]]: index, %[[VAL_1:.*]]: index, %[[VAL_2:.*]]: index) -> f32 {
 // CHECK-NEXT:    %[[VAL_3:.*]] = arith.constant 1.000000e+00 : f32
-// CHECK-NEXT:    %[[VAL_4:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-// CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_4]] : f32
-// CHECK-NEXT:    emitc.for %[[VAL_6:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:      %[[VAL_7:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-// CHECK-NEXT:      emitc.assign %[[VAL_4]] : f32 to %[[VAL_7]] : f32
-// CHECK-NEXT:      emitc.for %[[VAL_9:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:        %[[VAL_10:.*]] = arith.addf %[[VAL_7]], %[[VAL_7]] : f32
-// CHECK-NEXT:        emitc.assign %[[VAL_10]] : f32 to %[[VAL_7]] : f32
+// CHECK-NEXT:    %[[VAL_4:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+// CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_4]] : <f32>
+// CHECK-NEXT:    emitc.for %[[VAL_5:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
+// CHECK-NEXT:      %[[VAL_6:.*]] = emitc.lvalue_load %[[VAL_4]] : <f32>
+// CHECK-NEXT:      %[[VAL_7:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+// CHECK-NEXT:      emitc.assign %[[VAL_6]] : f32 to %[[VAL_7]] : <f32>
+// CHECK-NEXT:      emitc.for %[[VAL_8:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
+// CHECK-NEXT:        %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_7]] : <f32>  
+// CHECK-NEXT:        %[[VAL_10:.*]] = arith.addf %[[VAL_9]], %[[VAL_9]] : f32
+// CHECK-NEXT:        emitc.assign %[[VAL_10]] : f32 to %[[VAL_7]] : <f32>
 // CHECK-NEXT:      }
-// CHECK-NEXT:      emitc.assign %[[VAL_7]] : f32 to %[[VAL_4]] : f32
+// CHECK-NEXT:      %[[VAL_11:.*]] = emitc.lvalue_load %[[VAL_7]] : <f32>  
+// CHECK-NEXT:      emitc.assign %[[VAL_11]] : f32 to %[[VAL_4]] : <f32>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    return %[[VAL_4]] : f32
+// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.lvalue_load %[[VAL_4]] : <f32>  
+// CHECK-NEXT:    return %[[VAL_12]] : f32
 // CHECK-NEXT:  }
diff --git a/mlir/test/Conversion/SCFToEmitC/if.mlir b/mlir/test/Conversion/SCFToEmitC/if.mlir
index afc9abc761eb4..463cf1d3d9645 100644
--- a/mlir/test/Conversion/SCFToEmitC/if.mlir
+++ b/mlir/test/Conversion/SCFToEmitC/if.mlir
@@ -36,7 +36,7 @@ func.func @test_if_else(%arg0: i1, %arg1: f32) {
 // CHECK-NEXT:  }
 
 
-func.func @test_if_yield(%arg0: i1, %arg1: f32) {
+func.func @test_if_yield(%arg0: i1, %arg1: f32) -> (i32, f64) {
   %0 = arith.constant 0 : i8
   %x, %y = scf.if %arg0 -> (i32, f64) {
     %1 = emitc.call_opaque "func_true_1"(%arg1) : (f32) -> i32
@@ -47,24 +47,26 @@ func.func @test_if_yield(%arg0: i1, %arg1: f32) {
     %2 = emitc.call_opaque "func_false_2"(%arg1) : (f32) -> f64
     scf.yield %1, %2 : i32, f64
   }
-  return
+  return %x, %y : i32, f64
 }
 // CHECK-LABEL: func.func @test_if_yield(
 // CHECK-SAME:                           %[[VAL_0:.*]]: i1,
-// CHECK-SAME:                           %[[VAL_1:.*]]: f32) {
+// CHECK-SAME:                           %[[VAL_1:.*]]: f32) -> (i32, f64) {
 // CHECK-NEXT:    %[[VAL_2:.*]] = arith.constant 0 : i8
-// CHECK-NEXT:    %[[VAL_3:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> i32
-// CHECK-NEXT:    %[[VAL_4:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f64
+// CHECK-NEXT:    %[[VAL_3:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+// CHECK-NEXT:    %[[VAL_4:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f64>
 // CHECK-NEXT:    emitc.if %[[VAL_0]] {
 // CHECK-NEXT:      %[[VAL_5:.*]] = emitc.call_opaque "func_true_1"(%[[VAL_1]]) : (f32) -> i32
 // CHECK-NEXT:      %[[VAL_6:.*]] = emitc.call_opaque "func_true_2"(%[[VAL_1]]) : (f32) -> f64
-// CHECK-NEXT:      emitc.assign %[[VAL_5]] : i32 to %[[VAL_3]] : i32
-// CHECK-NEXT:      emitc.assign %[[VAL_6]] : f64 to %[[VAL_4]] : f64
+// CHECK-NEXT:      emitc.assign %[[VAL_5]] : i32 to %[[VAL_3]] : <i32>
+// CHECK-NEXT:      emitc.assign %[[VAL_6]] : f64 to %[[VAL_4]] : <f64>
 // CHECK-NEXT:    } else {
 // CHECK-NEXT:      %[[VAL_7:.*]] = emitc.call_opaque "func_false_1"(%[[VAL_1]]) : (f32) -> i32
 // CHECK-NEXT:      %[[VAL_8:.*]] = emitc.call_opaque "func_false_2"(%[[VAL_1]]) : (f32) -> f64
-// CHECK-NEXT:      emitc.assign %[[VAL_7]] : i32 to %[[VAL_3]] : i32
-// CHECK-NEXT:      emitc.assign %[[VAL_8]] : f64 to %[[VAL_4]] : f64
+// CHECK-NEXT:      emitc.assign %[[VAL_7]] : i32 to %[[VAL_3]] : <i32>
+// CHECK-NEXT:      emitc.assign %[[VAL_8]] : f64 to %[[VAL_4]] : <f64>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    return
+// CHECK-NEXT:    %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_3]] : <i32>
+// CHECK-NEXT:    %[[VAL_10:.*]] = emitc.lvalue_load %[[VAL_4]] : <f64>
+// CHECK-NEXT:    return %[[VAL_9]], %[[VAL_10]] : i32, f64
 // CHECK-NEXT:  }
diff --git a/mlir/test/Dialect/EmitC/invalid_ops.mlir b/mlir/test/Dialect/EmitC/invalid_ops.mlir
index 21ea6a5df91b9..261e67607fc4f 100644
--- a/mlir/test/Dialect/EmitC/invalid_ops.mlir
+++ b/mlir/test/Dialect/EmitC/invalid_ops.mlir
@@ -88,26 +88,17 @@ func.func @array_result() {
 
 // -----
 
-func.func @empty_operator(%arg : i32) {
+func.func @empty_operator(%arg : !emitc.lvalue<i32>) {
     // expected-error @+1 {{'emitc.apply' op applicable operator must not be empty}}
-    %2 = emitc.apply ""(%arg) : (i32) -> !emitc.ptr<i32>
+    %2 = emitc.apply ""(%arg) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
     return
 }
 
 // -----
 
-func.func @illegal_operator(%arg : i32) {
+func.func @illegal_operator(%arg : !emitc.lvalue<i32>) {
     // expected-error @+1 {{'emitc.apply' op applicable operator is illegal}}
-    %2 = emitc.apply "+"(%arg) : (i32) -> !emitc.ptr<i32>
-    return
-}
-
-// -----
-
-func.func @illegal_operand() {
-    %1 = "emitc.constant"(){value = 42: i32} : () -> i32
-    // expected-error @+1 {{'emitc.apply' op cannot apply to constant}}
-    %2 = emitc.apply "&"(%1) : (i32) -> !emitc.ptr<i32>
+    %2 = emitc.apply "+"(%arg) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
     return
 }
 
@@ -115,7 +106,7 @@ func.func @illegal_operand() {
 
 func.func @var_attribute_return_type_1() {
     // expected-error @+1 {{'emitc.variable' op requires attribute to either be an #emitc.opaque attribute or it's type ('i64') to match the op's result type ('i32')}}
-    %c0 = "emitc.variable"(){value = 42: i64} : () -> i32
+    %c0 = "emitc.variable"(){value = 42: i64} : () -> !emitc.lvalue<i32>
     return
 }
 
@@ -123,7 +114,7 @@ func.func @var_attribute_return_type_1() {
 
 func.func @var_attribute_return_type_2() {
     // expected-error @+1 {{'emitc.variable' op attribute 'value' failed to satisfy constraint: An opaque attribute or TypedAttr instance}}
-    %c0 = "emitc.variable"(){value = unit} : () -> i32
+    %c0 = "emitc.variable"(){value = unit} : () -> !emitc.lvalue<i32>
     return
 }
 
@@ -234,18 +225,18 @@ func.func @test_misplaced_yield() {
 
 // -----
 
-func.func @test_assign_to_non_variable(%arg1: f32, %arg2: f32) {
-  // expected-error @+1 {{'emitc.assign' op requires first operand (<block argument> of type 'f32' at index: 1) to be a Variable or subscript}}
-  emitc.assign %arg1 : f32 to %arg2 : f32
+func.func @test_assign_to_non_variable(%arg1: f32, %arg2: !emitc.lvalue<f32>) {
+  // expected-error @+1 {{'emitc.assign' op cannot assign to block argument}}
+  emitc.assign %arg1 : f32 to %arg2 : !emitc.lvalue<f32>
   return
 }
 
 // -----
 
 func.func @test_assign_type_mismatch(%arg1: f32) {
-  %v = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> i32
+  %v = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
   // expected-error @+1 {{'emitc.assign' op requires value's type ('f32') to match variable's type ('i32')}}
-  emitc.assign %arg1 : f32 to %v : i32
+  emitc.assign %arg1 : f32 to %v : !emitc.lvalue<i32>
   return
 }
 
@@ -253,7 +244,7 @@ func.func @test_assign_type_mismatch(%arg1: f32) {
 
 func.func @test_assign_to_array(%arg1: !emitc.array<4xi32>) {
   %v = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.array<4xi32>
-  // expected-error @+1 {{'emitc.assign' op cannot assign to array type}}
+  // expected-error @+1 {{invalid kind of Type specified}}
   emitc.assign %arg1 : !emitc.array<4xi32> to %v : !emitc.array<4xi32>
   return
 }
@@ -392,7 +383,7 @@ func.func @logical_or_resulterror(%arg0: i32, %arg1: i32) {
 
 func.func @test_subscript_array_indices_mismatch(%arg0: !emitc.array<4x8xf32>, %arg1: index) {
   // expected-error @+1 {{'emitc.subscript' op on array operand requires number of indices (1) to match the rank of the array type (2)}}
-  %0 = emitc.subscript %arg0[%arg1] : (!emitc.array<4x8xf32>, index) -> f32
+  %0 = emitc.subscript %arg0[%arg1] : (!emitc.array<4x8xf32>, index) -> !emitc.lvalue<f32>
   return
 }
 
@@ -400,7 +391,7 @@ func.func @test_subscript_array_indices_mismatch(%arg0: !emitc.array<4x8xf32>, %
 
 func.func @test_subscript_array_index_type_mismatch(%arg0: !emitc.array<4x8xf32>, %arg1: index, %arg2: f32) {
   // expected-error @+1 {{'emitc.subscript' op on array operand requires index operand 1 to be integer-like, but got 'f32'}}
-  %0 = emitc.subscript %arg0[%arg1, %arg2] : (!emitc.array<4x8xf32>, index, f32) -> f32
+  %0 = emitc.subscript %arg0[%arg1, %arg2] : (!emitc.array<4x8xf32>, index, f32) -> !emitc.lvalue<f32>
   return
 }
 
@@ -408,7 +399,7 @@ func.func @test_subscript_array_index_type_mismatch(%arg0: !emitc.array<4x8xf32>
 
 func.func @test_subscript_array_type_mismatch(%arg0: !emitc.array<4x8xf32>, %arg1: index, %arg2: index) {
   // expected-error @+1 {{'emitc.subscript' op on array operand requires element type ('f32') and result type ('i32') to match}}
-  %0 = emitc.subscript %arg0[%arg1, %arg2] : (!emitc.array<4x8xf32>, index, index) -> i32
+  %0 = emitc.subscript %arg0[%arg1, %arg2] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<i32>
   return
 }
 
@@ -416,7 +407,7 @@ func.func @test_subscript_array_type_mismatch(%arg0: !emitc.array<4x8xf32>, %arg
 
 func.func @test_subscript_ptr_indices_mismatch(%arg0: !emitc.ptr<f32>, %arg1: index) {
   // expected-error @+1 {{'emitc.subscript' op on pointer operand requires one index operand, but got 2}}
-  %0 = emitc.subscript %arg0[%arg1, %arg1] : (!emitc.ptr<f32>, index, index) -> f32
+  %0 = emitc.subscript %arg0[%arg1, %arg1] : (!emitc.ptr<f32>, index, index) -> !emitc.lvalue<f32>
   return
 }
 
@@ -424,7 +415,7 @@ func.func @test_subscript_ptr_indices_mismatch(%arg0: !emitc.ptr<f32>, %arg1: in
 
 func.func @test_subscript_ptr_index_type_mismatch(%arg0: !emitc.ptr<f32>, %arg1: f64) {
   // expected-error @+1 {{'emitc.subscript' op on pointer operand requires index operand to be integer-like, but got 'f64'}}
-  %0 = emitc.subscript %arg0[%arg1] : (!emitc.ptr<f32>, f64) -> f32
+  %0 = emitc.subscript %arg0[%arg1] : (!emitc.ptr<f32>, f64) -> !emitc.lvalue<f32>
   return
 }
 
@@ -432,7 +423,7 @@ func.func @test_subscript_ptr_index_type_mismatch(%arg0: !emitc.ptr<f32>, %arg1:
 
 func.func @test_subscript_ptr_type_mismatch(%arg0: !emitc.ptr<f32>, %arg1: index) {
   // expected-error @+1 {{'emitc.subscript' op on pointer operand requires pointee type ('f32') and result type ('f64') to match}}
-  %0 = emitc.subscript %arg0[%arg1] : (!emitc.ptr<f32>, index) -> f64
+  %0 = emitc.subscript %arg0[%arg1] : (!emitc.ptr<f32>, index) -> !emitc.lvalue<f64>
   return
 }
 
@@ -443,10 +434,20 @@ emitc.global extern static @uninit : i32
 
 // -----
 
-emitc.global @myglobal : !emitc.array<2xf32>
+emitc.global @myglobal_array : !emitc.array<2xf32>
+
+func.func @use_global() {
+  // expected-error @+1 {{'emitc.get_global' op on array type expects result type '!emitc.array<3xf32>' to match type '!emitc.array<2xf32>' of the global @myglobal_array}}
+  %0 = emitc.get_global @myglobal_array : !emitc.array<3xf32>
+  return
+}
+
+// -----
+
+emitc.global @myglobal_scalar : f32
 
 func.func @use_global() {
-  // expected-error @+1 {{'emitc.get_global' op result type 'f32' does not match type '!emitc.array<2xf32>' of the global @myglobal}}
-  %0 = emitc.get_global @myglobal : f32
+  // expected-error @+1 {{'emitc.get_global' op on non-array type expects result inner type 'i32' to match type 'f32' of the global @myglobal_scalar}}
+  %0 = emitc.get_global @myglobal_scalar : !emitc.lvalue<i32>
   return
 }
diff --git a/mlir/test/Dialect/EmitC/invalid_types.mlir b/mlir/test/Dialect/EmitC/invalid_types.mlir
index 0ad8d4eabe6b8..07f2dfe583c3d 100644
--- a/mlir/test/Dialect/EmitC/invalid_types.mlir
+++ b/mlir/test/Dialect/EmitC/invalid_types.mlir
@@ -84,6 +84,14 @@ func.func @illegal_array_with_tensor_element_type(
 
 // -----
 
+func.func @illegal_array_with_lvalue_element_type(
+    // expected-error @+1 {{invalid array element type}}
+    %arg0: !emitc.array<4x!emitc.lvalue<i32>>
+) {
+}
+
+// -----
+
 func.func @illegal_integer_type(%arg0: i11, %arg1: i11) -> i11 {
     // expected-error @+1 {{'emitc.mul' op operand #0 must be floating-point type supported by EmitC or integer type supported by EmitC or index or EmitC opaque type, but got 'i11'}}
     %mul = "emitc.mul" (%arg0, %arg1) : (i11, i11) -> i11
@@ -100,48 +108,80 @@ func.func @illegal_float_type(%arg0: f80, %arg1: f80) {
 
 // -----
 
-func.func @illegal_pointee_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got '!emitc.ptr<i11>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.ptr<i11>
+func.func @illegal_lvalue_type_1() {
+    // expected-error @+1 {{!emitc.lvalue cannot wrap !emitc.array type}}
+    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<!emitc.array<1xi32>>
+    return
+}
+
+// -----
+
+func.func @illegal_lvalue_type_2() {
+    // expected-error @+1 {{!emitc.lvalue must wrap supported emitc type, but got '!emitc.lvalue<i32>'}}
+    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<!emitc.lvalue<i32>>
+    return
+}
+
+// -----
+
+func.func @illegal_lvalue_type_3() {
+    // expected-error @+1 {{!emitc.lvalue must wrap supported emitc type, but got 'i17'}}
+    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i17>
+    return
+}
+
+// -----
+
+func.func @illegal_pointee_type_1() {
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got '!emitc.ptr<i11>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> !emitc.ptr<i11>
+    return
+}
+
+// -----
+
+func.func @illegal_pointee_type_2() {
+    // expected-error @+1 {{pointers to lvalues are not allowed}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"NULL">} : () -> !emitc.ptr<!emitc.lvalue<i32>>
     return
 }
 
 // -----
 
 func.func @illegal_non_static_tensor_shape_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got 'tensor<?xf32>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> tensor<?xf32>
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got 'tensor<?xf32>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> tensor<?xf32>
     return
 }
 
 // -----
 
 func.func @illegal_tensor_array_element_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got 'tensor<!emitc.array<9xi16>>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> tensor<!emitc.array<9xi16>>
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got 'tensor<!emitc.array<9xi16>>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> tensor<!emitc.array<9xi16>>
     return
 }
 
 // -----
 
 func.func @illegal_tensor_integer_element_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got 'tensor<9xi11>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> tensor<9xi11>
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got 'tensor<9xi11>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> tensor<9xi11>
     return
 }
 
 // -----
 
 func.func @illegal_tuple_array_element_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got 'tuple<!emitc.array<9xf32>, f32>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> tuple<!emitc.array<9xf32>, f32>
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got 'tuple<!emitc.array<9xf32>, f32>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> tuple<!emitc.array<9xf32>, f32>
     return
 }
 
 // -----
 
 func.func @illegal_tuple_float_element_type() {
-    // expected-error @+1 {{'emitc.variable' op result #0 must be type supported by EmitC, but got 'tuple<i32, f80>'}}
-    %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> tuple<i32, f80>
+    // expected-error @+1 {{'emitc.constant' op result #0 must be type supported by EmitC, but got 'tuple<i32, f80>'}}
+    %v = "emitc.constant"(){value = #emitc.opaque<"{}">} : () -> tuple<i32, f80>
     return
 }
diff --git a/mlir/test/Dialect/EmitC/ops.mlir b/mlir/test/Dialect/EmitC/ops.mlir
index 05510e6dddbf5..616a7ddbbf672 100644
--- a/mlir/test/Dialect/EmitC/ops.mlir
+++ b/mlir/test/Dialect/EmitC/ops.mlir
@@ -44,9 +44,9 @@ func.func @c() {
   return
 }
 
-func.func @a(%arg0: i32, %arg1: i32) {
-  %1 = "emitc.apply"(%arg0) {applicableOperator = "&"} : (i32) -> !emitc.ptr<i32>
-  %2 = emitc.apply "&"(%arg1) : (i32) -> !emitc.ptr<i32>
+func.func @a(%arg0: !emitc.lvalue<i32>, %arg1: !emitc.lvalue<i32>) {
+  %1 = "emitc.apply"(%arg0) {applicableOperator = "&"} : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  %2 = emitc.apply "&"(%arg1) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   return
 }
 
@@ -170,8 +170,8 @@ func.func @test_if_else(%arg0: i1, %arg1: f32) {
 }
 
 func.func @test_assign(%arg1: f32) {
-  %v = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-  emitc.assign %arg1 : f32 to %v : f32
+  %v = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  emitc.assign %arg1 : f32 to %v : !emitc.lvalue<f32>
   return
 }
 
@@ -215,9 +215,9 @@ func.func @test_for_not_index_induction(%arg0 : i16, %arg1 : i16, %arg2 : i16) {
 }
 
 func.func @test_subscript(%arg0 : !emitc.array<2x3xf32>, %arg1 : !emitc.ptr<i32>, %arg2 : !emitc.opaque<"std::map<char, int>">, %idx0 : index, %idx1 : i32, %idx2 : !emitc.opaque<"char">) {
-  %0 = emitc.subscript %arg0[%idx0, %idx1] : (!emitc.array<2x3xf32>, index, i32) -> f32
-  %1 = emitc.subscript %arg1[%idx0] : (!emitc.ptr<i32>, index) -> i32
-  %2 = emitc.subscript %arg2[%idx2] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.opaque<"int">
+  %0 = emitc.subscript %arg0[%idx0, %idx1] : (!emitc.array<2x3xf32>, index, i32) -> !emitc.lvalue<f32>
+  %1 = emitc.subscript %arg1[%idx0] : (!emitc.ptr<i32>, index) -> !emitc.lvalue<i32>
+  %2 = emitc.subscript %arg2[%idx2] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.lvalue<!emitc.opaque<"int">>
   return
 }
 
@@ -242,6 +242,7 @@ emitc.global const @myconstant : !emitc.array<2xi16> = dense<2>
 
 func.func @use_global(%i: index) -> f32 {
   %0 = emitc.get_global @myglobal : !emitc.array<2xf32>
-  %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> f32
-  return %1 : f32
+  %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> !emitc.lvalue<f32>
+  %2 = emitc.lvalue_load %1 : <f32>
+  return %2 : f32
 }
diff --git a/mlir/test/Dialect/EmitC/transforms.mlir b/mlir/test/Dialect/EmitC/transforms.mlir
index a5c582be4aa7f..996fd327f7af7 100644
--- a/mlir/test/Dialect/EmitC/transforms.mlir
+++ b/mlir/test/Dialect/EmitC/transforms.mlir
@@ -64,50 +64,24 @@ func.func @expression_with_call(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32)
   return %c : i1
 }
 
-// CHECK-LABEL: func.func @expression_with_dereference(
-// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>) -> i1 {
-// CHECK:         %[[VAL_3:.*]] = emitc.expression : i32 {
-// CHECK:           %[[VAL_4:.*]] = emitc.apply "*"(%[[VAL_2]]) : (!emitc.ptr<i32>) -> i32
-// CHECK:           emitc.yield %[[VAL_4]] : i32
-// CHECK:         }
-// CHECK:         %[[VAL_5:.*]] = emitc.expression : i1 {
-// CHECK:           %[[VAL_6:.*]] = emitc.mul %[[VAL_0]], %[[VAL_1]] : (i32, i32) -> i32
-// CHECK:           %[[VAL_7:.*]] = emitc.cmp lt, %[[VAL_6]], %[[VAL_3]] : (i32, i32) -> i1
+// CHECK-LABEL: func.func @expression_with_address_taken(
+// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>, %[[VAL_3:.*]]: !emitc.lvalue<i32>) -> i1 {
+// CHECK:         %[[VAL_4:.*]] = emitc.expression : i1 {
+// CHECK:           %[[VAL_5:.*]] = emitc.apply "&"(%[[VAL_3]]) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+// CHECK:           %[[VAL_6:.*]] = emitc.add %[[VAL_5]], %[[VAL_1]] : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
+// CHECK:           %[[VAL_7:.*]] = emitc.cmp lt, %[[VAL_6]], %[[VAL_2]] : (!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
 // CHECK:           emitc.yield %[[VAL_7]] : i1
 // CHECK:         }
-// CHECK:         return %[[VAL_5]] : i1
+// CHECK:         return %[[VAL_4]] : i1
 // CHECK:       }
 
-func.func @expression_with_dereference(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>) -> i1 {
-  %a = emitc.mul %arg0, %arg1 : (i32, i32) -> i32
-  %b = emitc.apply "*"(%arg2) : (!emitc.ptr<i32>) -> (i32)
-  %c = emitc.cmp lt, %a, %b :(i32, i32) -> i1
+func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>, %arg3: !emitc.lvalue<i32>) -> i1 {
+  %a = emitc.apply "&"(%arg3) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  %b = emitc.add %a, %arg1 : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
+  %c = emitc.cmp lt, %b, %arg2 :(!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
   return %c : i1
 }
 
-// CHECK-LABEL: func.func @expression_with_address_taken(
-// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>) -> i1 {
-// CHECK:         %[[VAL_3:.*]] = emitc.expression : i32 {
-// CHECK:           %[[VAL_4:.*]] = emitc.rem %[[VAL_0]], %[[VAL_1]] : (i32, i32) -> i32
-// CHECK:           emitc.yield %[[VAL_4]] : i32
-// CHECK:         }
-// CHECK:         %[[VAL_5:.*]] = emitc.expression : i1 {
-// CHECK:           %[[VAL_6:.*]] = emitc.apply "&"(%[[VAL_3]]) : (i32) -> !emitc.ptr<i32>
-// CHECK:           %[[VAL_7:.*]] = emitc.add %[[VAL_6]], %[[VAL_1]] : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
-// CHECK:           %[[VAL_8:.*]] = emitc.cmp lt, %[[VAL_7]], %[[VAL_2]] : (!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
-// CHECK:           emitc.yield %[[VAL_8]] : i1
-// CHECK:         }
-// CHECK:         return %[[VAL_5]] : i1
-// CHECK:       }
-
-func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>) -> i1 {
-  %a = emitc.rem %arg0, %arg1 : (i32, i32) -> (i32)
-  %b = emitc.apply "&"(%a) : (i32) -> !emitc.ptr<i32>
-  %c = emitc.add %b, %arg1 : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
-  %d = emitc.cmp lt, %c, %arg2 :(!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
-  return %d : i1
-}
-
 // CHECK-LABEL: func.func @no_nested_expression(
 // CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32) -> i1 {
 // CHECK:         %[[VAL_2:.*]] = emitc.expression : i1 {
diff --git a/mlir/test/Dialect/EmitC/types.mlir b/mlir/test/Dialect/EmitC/types.mlir
index 752f2c10c17be..a81c3703af23b 100644
--- a/mlir/test/Dialect/EmitC/types.mlir
+++ b/mlir/test/Dialect/EmitC/types.mlir
@@ -1,6 +1,6 @@
-// RUN: mlir-opt -verify-diagnostics %s | FileCheck %s
+// RUN: mlir-opt -verify-diagnostics -allow-unregistered-dialect %s | FileCheck %s
 // check parser
-// RUN: mlir-opt -verify-diagnostics %s | mlir-opt -verify-diagnostics | FileCheck %s
+// RUN: mlir-opt -verify-diagnostics -allow-unregistered-dialect %s | mlir-opt -verify-diagnostics --allow-unregistered-dialect | FileCheck %s
 
 // CHECK-LABEL: func @array_types(
 func.func @array_types(
@@ -16,6 +16,21 @@ func.func @array_types(
   return
 }
 
+// CHECK-LABEL: func @lvalue_types(
+func.func @lvalue_types() {
+  // CHECK-NEXT: !emitc.lvalue<i32>
+  %0 = "typed.result"() : () -> (!emitc.lvalue<i32>)
+  // CHECK-NEXT: !emitc.lvalue<f64>
+  %2 = "typed.result"() : () -> (!emitc.lvalue<f64>)
+  // CHECK-NEXT: !emitc.lvalue<index>
+  %3 = "typed.result"() : () -> (!emitc.lvalue<index>)
+  // CHECK-NEXT: !emitc.lvalue<!emitc.ptr<i32>>
+  %4 = "typed.result"() : () -> (!emitc.lvalue<!emitc.ptr<i32>>)
+  // CHECK-NEXT: !emitc.lvalue<!emitc.opaque<"int">>
+  %5 = "typed.result"() : () -> (!emitc.lvalue<!emitc.opaque<"int">>)
+  return
+}
+
 // CHECK-LABEL: func @opaque_types() {
 func.func @opaque_types() {
   // CHECK-NEXT: !emitc.opaque<"int">
diff --git a/mlir/test/Target/Cpp/common-cpp.mlir b/mlir/test/Target/Cpp/common-cpp.mlir
index 0e24bdd19993f..8af29531905ba 100644
--- a/mlir/test/Target/Cpp/common-cpp.mlir
+++ b/mlir/test/Target/Cpp/common-cpp.mlir
@@ -82,11 +82,18 @@ func.func @opaque_types(%arg0: !emitc.opaque<"bool">, %arg1: !emitc.opaque<"char
   return %2 : !emitc.opaque<"status_t">
 }
 
-func.func @apply(%arg0: i32) -> !emitc.ptr<i32> {
-  // CHECK: int32_t* [[V2]] = &[[V1]];
-  %0 = emitc.apply "&"(%arg0) : (i32) -> !emitc.ptr<i32>
-  // CHECK: int32_t [[V3]] = *[[V2]];
-  %1 = emitc.apply "*"(%0) : (!emitc.ptr<i32>) -> (i32)
+// CHECK-LABEL: int32_t* apply(
+// CHECK-SAME: int32_t [[V1:[^ ]*]]) {
+func.func @apply(%arg0: !emitc.lvalue<i32>) -> !emitc.ptr<i32> {
+  // CHECK-NEXT: int32_t* [[V2:[^ ]*]] = &[[V1]];
+  %0 = emitc.apply "&"(%arg0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  // CHECK-NEXT: int32_t [[V3:[^ ]*]];
+  %2 = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
+  // CHECK-NEXT: int32_t [[V4:[^ ]*]] = *[[V2]];
+  %1 = emitc.apply "*"(%0) : (!emitc.ptr<i32>) -> i32
+  // CHECK-NEXT: [[V3]] = [[V4]];
+  emitc.assign %1 : i32 to %2 : !emitc.lvalue<i32>
+  // CHECK-NEXT: return [[V2]];
   return %0 : !emitc.ptr<i32>
 }
 
diff --git a/mlir/test/Target/Cpp/expressions.mlir b/mlir/test/Target/Cpp/expressions.mlir
index caa0a340d3e0a..d9455e8e98177 100644
--- a/mlir/test/Target/Cpp/expressions.mlir
+++ b/mlir/test/Target/Cpp/expressions.mlir
@@ -9,12 +9,14 @@
 // CPP-DEFAULT-NEXT:   } else {
 // CPP-DEFAULT-NEXT:     [[VAL_6]] = [[VAL_1]];
 // CPP-DEFAULT-NEXT:   }
-// CPP-DEFAULT-NEXT:   return [[VAL_6]];
+// CPP-DEFAULT-NEXT:   int32_t [[VAL_7:v[0-9]+]] = [[VAL_6]];
+// CPP-DEFAULT-NEXT:   return [[VAL_7]];
 // CPP-DEFAULT-NEXT: }
 
 // CPP-DECLTOP:      int32_t single_use(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]], int32_t [[VAL_4:v[0-9]+]]) {
 // CPP-DECLTOP-NEXT:   bool [[VAL_5:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_6:v[0-9]+]];
+// CPP-DECLTOP-NEXT:   int32_t [[VAL_7:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   [[VAL_5]] = bar([[VAL_1]] * M_PI, [[VAL_3]]) - [[VAL_4]] < [[VAL_2]];
 // CPP-DECLTOP-NEXT:   ;
 // CPP-DECLTOP-NEXT:   if ([[VAL_5]]) {
@@ -22,7 +24,8 @@
 // CPP-DECLTOP-NEXT:   } else {
 // CPP-DECLTOP-NEXT:     [[VAL_6]] = [[VAL_1]];
 // CPP-DECLTOP-NEXT:   }
-// CPP-DECLTOP-NEXT:   return [[VAL_6]];
+// CPP-DECLTOP-NEXT:   [[VAL_7]] = [[VAL_6]];
+// CPP-DECLTOP-NEXT:   return [[VAL_7]];
 // CPP-DECLTOP-NEXT: }
 
 func.func @single_use(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32 {
@@ -34,15 +37,16 @@ func.func @single_use(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32 {
     %d = emitc.cmp lt, %c, %arg1 :(i32, i32) -> i1
     emitc.yield %d : i1
   }
-  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i32
+  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
   emitc.if %e {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   } else {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   }
-  return %v : i32
+  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  return %v_load : i32
 }
 
 // CPP-DEFAULT: int32_t do_not_inline(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]]) {
@@ -175,8 +179,8 @@ func.func @user_with_expression_trait(%arg0: i32, %arg1: i32, %arg2: i32) -> i32
   %add = emitc.add %e1, %c0 : (i32, i32) -> i32
   %call = emitc.call_opaque "bar" (%e2, %c0) : (i32, i32) -> (i32)
   %cond = emitc.conditional %cast, %e3, %c0 : i32
-  %var = "emitc.variable"() {value = #emitc.opaque<"">} : () -> i32
-  emitc.assign %e4 : i32 to %var : i32
+  %var = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
+  emitc.assign %e4 : i32 to %var : !emitc.lvalue<i32>
   return %e5 : i32
 }
 
@@ -190,13 +194,15 @@ func.func @user_with_expression_trait(%arg0: i32, %arg1: i32, %arg2: i32) -> i32
 // CPP-DEFAULT-NEXT:   }
 // CPP-DEFAULT-NEXT:   bool [[VAL_7:v[0-9]+]];
 // CPP-DEFAULT-NEXT:   [[VAL_7]] = [[VAL_5]];
-// CPP-DEFAULT-NEXT:   return [[VAL_6]];
+// CPP-DEFAULT-NEXT:   int32_t [[VAL_8:v[0-9]+]] = [[VAL_6]];
+// CPP-DEFAULT-NEXT:   return [[VAL_8]];
 // CPP-DEFAULT-NEXT: }
 
 // CPP-DECLTOP:      int32_t multiple_uses(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]], int32_t [[VAL_4:v[0-9]+]]) {
 // CPP-DECLTOP-NEXT:   bool [[VAL_5:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_6:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   bool [[VAL_7:v[0-9]+]];
+// CPP-DECLTOP-NEXT:   int32_t [[VAL_8:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   [[VAL_5]] = bar([[VAL_1]] * [[VAL_2]], [[VAL_3]]) - [[VAL_4]] < [[VAL_2]];
 // CPP-DECLTOP-NEXT:   ;
 // CPP-DECLTOP-NEXT:   if ([[VAL_5]]) {
@@ -206,7 +212,8 @@ func.func @user_with_expression_trait(%arg0: i32, %arg1: i32, %arg2: i32) -> i32
 // CPP-DECLTOP-NEXT:   }
 // CPP-DECLTOP-NEXT:   ;
 // CPP-DECLTOP-NEXT:   [[VAL_7]] = [[VAL_5]];
-// CPP-DECLTOP-NEXT:   return [[VAL_6]];
+// CPP-DECLTOP-NEXT:   [[VAL_8]] = [[VAL_6]];
+// CPP-DECLTOP-NEXT:   return [[VAL_8]];
 // CPP-DECLTOP-NEXT: }
 
 func.func @multiple_uses(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32 {
@@ -217,17 +224,18 @@ func.func @multiple_uses(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32
     %d = emitc.cmp lt, %c, %arg1 :(i32, i32) -> i1
     emitc.yield %d : i1
   }
-  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i32
+  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
   emitc.if %e {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   } else {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   }
-  %q = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i1
-  emitc.assign %e : i1 to %q : i1
-  return %v : i32
+  %q = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i1>
+  emitc.assign %e : i1 to %q : !emitc.lvalue<i1>
+  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  return %v_load : i32
 }
 
 // CPP-DEFAULT:      int32_t different_expressions(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]], int32_t [[VAL_4:v[0-9]+]]) {
@@ -239,13 +247,15 @@ func.func @multiple_uses(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32
 // CPP-DEFAULT-NEXT:   } else {
 // CPP-DEFAULT-NEXT:     [[VAL_7]] = [[VAL_1]];
 // CPP-DEFAULT-NEXT:   }
-// CPP-DEFAULT-NEXT:   return [[VAL_7]];
+// CPP-DEFAULT-NEXT:   int32_t [[VAL_8:v[0-9]+]] = [[VAL_7]];
+// CPP-DEFAULT-NEXT:   return [[VAL_8]];
 // CPP-DEFAULT-NEXT: }
 
 // CPP-DECLTOP:      int32_t different_expressions(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]], int32_t [[VAL_4:v[0-9]+]]) {
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_5:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_6:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_7:v[0-9]+]];
+// CPP-DECLTOP-NEXT:   int32_t [[VAL_8:v[0-9]+]];
 // CPP-DECLTOP-NEXT:   [[VAL_5]] = [[VAL_3]] % [[VAL_4]];
 // CPP-DECLTOP-NEXT:   [[VAL_6]] = bar([[VAL_5]], [[VAL_1]] * [[VAL_2]]);
 // CPP-DECLTOP-NEXT:   ;
@@ -254,7 +264,8 @@ func.func @multiple_uses(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32
 // CPP-DECLTOP-NEXT:   } else {
 // CPP-DECLTOP-NEXT:     [[VAL_7]] = [[VAL_1]];
 // CPP-DECLTOP-NEXT:   }
-// CPP-DECLTOP-NEXT:   return [[VAL_7]];
+// CPP-DECLTOP-NEXT:   [[VAL_8]] = [[VAL_7]];
+// CPP-DECLTOP-NEXT:   return [[VAL_8]];
 // CPP-DECLTOP-NEXT: }
 
 func.func @different_expressions(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32 {
@@ -272,35 +283,33 @@ func.func @different_expressions(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32)
     %d = emitc.cmp lt, %c, %arg1 :(i32, i32) -> i1
     emitc.yield %d : i1
   }
-  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i32
+  %v = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
   emitc.if %e3 {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   } else {
-    emitc.assign %arg0 : i32 to %v : i32
+    emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   }
-  return %v : i32
+  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  return %v_load : i32
 }
 
 // CPP-DEFAULT:      bool expression_with_address_taken(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t* [[VAL_3]]) {
-// CPP-DEFAULT-NEXT:   int32_t [[VAL_4:v[0-9]+]] = [[VAL_1]] % [[VAL_2]];
+// CPP-DEFAULT-NEXT:   int32_t [[VAL_4:v[0-9]+]] = 42;
 // CPP-DEFAULT-NEXT:   return &[[VAL_4]] - [[VAL_2]] < [[VAL_3]];
 // CPP-DEFAULT-NEXT: }
 
 // CPP-DECLTOP:      bool expression_with_address_taken(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t* [[VAL_3]]) {
 // CPP-DECLTOP-NEXT:   int32_t [[VAL_4:v[0-9]+]];
-// CPP-DECLTOP-NEXT:   [[VAL_4]] = [[VAL_1]] % [[VAL_2]];
+// CPP-DECLTOP-NEXT:   [[VAL_4]] = 42;
 // CPP-DECLTOP-NEXT:   return &[[VAL_4]] - [[VAL_2]] < [[VAL_3]];
 // CPP-DECLTOP-NEXT: }
 
 func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>) -> i1 {
-  %a = emitc.expression : i32 {
-    %b = emitc.rem %arg0, %arg1 : (i32, i32) -> i32
-    emitc.yield %b : i32
-  }
+  %a = "emitc.variable"(){value = 42 : i32} : () -> !emitc.lvalue<i32>
   %c = emitc.expression : i1 {
-    %d = emitc.apply "&"(%a) : (i32) -> !emitc.ptr<i32>
+    %d = emitc.apply "&"(%a) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
     %e = emitc.sub %d, %arg1 : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
     %f = emitc.cmp lt, %e, %arg2 : (!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
     emitc.yield %f : i1
@@ -311,7 +320,17 @@ func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.p
 // CPP-DEFAULT: int32_t expression_with_subscript_user(void* [[VAL_1:v.+]])
 // CPP-DEFAULT-NEXT:   int64_t [[VAL_2:v.+]] = 0;
 // CPP-DEFAULT-NEXT:   int32_t* [[VAL_3:v.+]] = (int32_t*) [[VAL_1]];
-// CPP-DEFAULT-NEXT:   return [[VAL_3]][[[VAL_2]]];
+// CPP-DEFAULT-NEXT:   int32_t [[VAL_4:v.+]] = [[VAL_3]][[[VAL_2]]];
+// CPP-DEFAULT-NEXT:   return [[VAL_4]];
+
+// CPP-DECLTOP: int32_t expression_with_subscript_user(void* [[VAL_1:v.+]])
+// CPP-DECLTOP-NEXT:   int64_t [[VAL_2:v.+]];
+// CPP-DECLTOP-NEXT:   int32_t* [[VAL_3:v.+]];
+// CPP-DECLTOP-NEXT:   int32_t [[VAL_4:v.+]];
+// CPP-DECLTOP-NEXT:   [[VAL_2]] = 0;
+// CPP-DECLTOP-NEXT:   [[VAL_3]] = (int32_t*) [[VAL_1]];
+// CPP-DECLTOP-NEXT:   [[VAL_4]] = [[VAL_3]][[[VAL_2]]];
+// CPP-DECLTOP-NEXT:   return [[VAL_4]];
 
 func.func @expression_with_subscript_user(%arg0: !emitc.ptr<!emitc.opaque<"void">>) -> i32 {
   %c0 = "emitc.constant"() {value = 0 : i64} : () -> i64
@@ -319,6 +338,7 @@ func.func @expression_with_subscript_user(%arg0: !emitc.ptr<!emitc.opaque<"void"
     %0 = emitc.cast %arg0 : !emitc.ptr<!emitc.opaque<"void">> to !emitc.ptr<i32>
     emitc.yield %0 : !emitc.ptr<i32>
   }
-  %1 = emitc.subscript %0[%c0] : (!emitc.ptr<i32>, i64) -> i32
-  return %1 : i32
+  %res = emitc.subscript %0[%c0] : (!emitc.ptr<i32>, i64) -> !emitc.lvalue<i32>
+  %res_load = emitc.lvalue_load %res : !emitc.lvalue<i32>
+  return %res_load : i32
 }
diff --git a/mlir/test/Target/Cpp/for.mlir b/mlir/test/Target/Cpp/for.mlir
index af1d829113f9d..14d3f05d6a08e 100644
--- a/mlir/test/Target/Cpp/for.mlir
+++ b/mlir/test/Target/Cpp/for.mlir
@@ -40,17 +40,25 @@ func.func @test_for_yield() {
   %s0 = "emitc.constant"() <{value = 0 : i32}> : () -> i32
   %p0 = "emitc.constant"() <{value = 1.0 : f32}> : () -> f32
 
-  %2 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> i32
-  %3 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-  emitc.assign %s0 : i32 to %2 : i32
-  emitc.assign %p0 : f32 to %3 : f32
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %1 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  %2 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %3 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  emitc.assign %s0 : i32 to %2 : !emitc.lvalue<i32>
+  emitc.assign %p0 : f32 to %3 : !emitc.lvalue<f32>
   emitc.for %iter = %start to %stop step %step {
-    %sn = emitc.call_opaque "add"(%2, %iter) : (i32, index) -> i32
-    %pn = emitc.call_opaque "mul"(%3, %iter) : (f32, index) -> f32
-    emitc.assign %sn : i32 to %2 : i32
-    emitc.assign %pn : f32 to %3 : f32
+    %4 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+    %sn = emitc.call_opaque "add"(%4, %iter) : (i32, index) -> i32
+    %5 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+    %pn = emitc.call_opaque "mul"(%5, %iter) : (f32, index) -> f32
+    emitc.assign %sn : i32 to %2 : !emitc.lvalue<i32>
+    emitc.assign %pn : f32 to %3 : !emitc.lvalue<f32>
     emitc.yield
   }
+  %6 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+  emitc.assign %6 : i32 to %0 : !emitc.lvalue<i32>
+  %7 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+  emitc.assign %7 : f32 to %1 : !emitc.lvalue<f32>
 
   return
 }
@@ -60,16 +68,24 @@ func.func @test_for_yield() {
 // CPP-DEFAULT-NEXT: size_t [[STEP:[^ ]*]] = 1;
 // CPP-DEFAULT-NEXT: int32_t [[S0:[^ ]*]] = 0;
 // CPP-DEFAULT-NEXT: float [[P0:[^ ]*]] = 1.000000000e+00f;
+// CPP-DEFAULT-NEXT: int32_t [[SE:[^ ]*]];
+// CPP-DEFAULT-NEXT: float [[PE:[^ ]*]];
 // CPP-DEFAULT-NEXT: int32_t [[SI:[^ ]*]];
 // CPP-DEFAULT-NEXT: float [[PI:[^ ]*]];
 // CPP-DEFAULT-NEXT: [[SI:[^ ]*]] = [[S0]];
 // CPP-DEFAULT-NEXT: [[PI:[^ ]*]] = [[P0]];
 // CPP-DEFAULT-NEXT: for (size_t [[ITER:[^ ]*]] = [[START]]; [[ITER]] < [[STOP]]; [[ITER]] += [[STEP]]) {
-// CPP-DEFAULT-NEXT: int32_t [[SN:[^ ]*]] = add([[SI]], [[ITER]]);
-// CPP-DEFAULT-NEXT: float [[PN:[^ ]*]] = mul([[PI]], [[ITER]]);
+// CPP-DEFAULT-NEXT: int32_t [[SI_LOAD:[^ ]*]] = [[SI]];
+// CPP-DEFAULT-NEXT: int32_t [[SN:[^ ]*]] = add([[SI_LOAD]], [[ITER]]);
+// CPP-DEFAULT-NEXT: float [[PI_LOAD:[^ ]*]] = [[PI]];
+// CPP-DEFAULT-NEXT: float [[PN:[^ ]*]] = mul([[PI_LOAD]], [[ITER]]);
 // CPP-DEFAULT-NEXT: [[SI]] = [[SN]];
 // CPP-DEFAULT-NEXT: [[PI]] = [[PN]];
 // CPP-DEFAULT-NEXT: }
+// CPP-DEFAULT-NEXT: int32_t [[SI_LOAD2:[^ ]*]] = [[SI]];
+// CPP-DEFAULT-NEXT: [[SE]] = [[SI_LOAD2]];
+// CPP-DEFAULT-NEXT: float [[PI_LOAD2:[^ ]*]] = [[PI]];
+// CPP-DEFAULT-NEXT: [[PE]] = [[PI_LOAD2]];
 // CPP-DEFAULT-NEXT: return;
 
 // CPP-DECLTOP: void test_for_yield() {
@@ -78,10 +94,16 @@ func.func @test_for_yield() {
 // CPP-DECLTOP-NEXT: size_t [[STEP:[^ ]*]];
 // CPP-DECLTOP-NEXT: int32_t [[S0:[^ ]*]];
 // CPP-DECLTOP-NEXT: float [[P0:[^ ]*]];
+// CPP-DECLTOP-NEXT: int32_t [[SE:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[PE:[^ ]*]];
 // CPP-DECLTOP-NEXT: int32_t [[SI:[^ ]*]];
 // CPP-DECLTOP-NEXT: float [[PI:[^ ]*]];
+// CPP-DECLTOP-NEXT: int32_t [[SI_LOAD:[^ ]*]];
 // CPP-DECLTOP-NEXT: int32_t [[SN:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[PI_LOAD:[^ ]*]];
 // CPP-DECLTOP-NEXT: float [[PN:[^ ]*]];
+// CPP-DECLTOP-NEXT: int32_t [[SI_LOAD2:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[PI_LOAD2:[^ ]*]];
 // CPP-DECLTOP-NEXT: [[START]] = 0;
 // CPP-DECLTOP-NEXT: [[STOP]] = 10;
 // CPP-DECLTOP-NEXT: [[STEP]] = 1;
@@ -89,14 +111,22 @@ func.func @test_for_yield() {
 // CPP-DECLTOP-NEXT: [[P0]] = 1.000000000e+00f;
 // CPP-DECLTOP-NEXT: ;
 // CPP-DECLTOP-NEXT: ;
-// CPP-DECLTOP-NEXT: [[SI:[^ ]*]] = [[S0]];
-// CPP-DECLTOP-NEXT: [[PI:[^ ]*]] = [[P0]];
+// CPP-DECLTOP-NEXT: ;
+// CPP-DECLTOP-NEXT: ;
+// CPP-DECLTOP-NEXT: [[SI]] = [[S0]];
+// CPP-DECLTOP-NEXT: [[PI]] = [[P0]];
 // CPP-DECLTOP-NEXT: for (size_t [[ITER:[^ ]*]] = [[START]]; [[ITER]] < [[STOP]]; [[ITER]] += [[STEP]]) {
-// CPP-DECLTOP-NEXT: [[SN]] = add([[SI]], [[ITER]]);
-// CPP-DECLTOP-NEXT: [[PN]] = mul([[PI]], [[ITER]]);
+// CPP-DECLTOP-NEXT: [[SI_LOAD]] = [[SI]];
+// CPP-DECLTOP-NEXT: [[SN]] = add([[SI_LOAD]], [[ITER]]);
+// CPP-DECLTOP-NEXT: [[PI_LOAD]] = [[PI]];
+// CPP-DECLTOP-NEXT: [[PN]] = mul([[PI_LOAD]], [[ITER]]);
 // CPP-DECLTOP-NEXT: [[SI]] = [[SN]];
 // CPP-DECLTOP-NEXT: [[PI]] = [[PN]];
 // CPP-DECLTOP-NEXT: }
+// CPP-DECLTOP-NEXT: [[SI_LOAD2]] = [[SI]];
+// CPP-DECLTOP-NEXT: [[SE]] = [[SI_LOAD2]];
+// CPP-DECLTOP-NEXT: [[PI_LOAD2]] = [[PI]];
+// CPP-DECLTOP-NEXT: [[PE]] = [[PI_LOAD2]];
 // CPP-DECLTOP-NEXT: return;
 
 func.func @test_for_yield_2() {
@@ -107,17 +137,25 @@ func.func @test_for_yield_2() {
   %s0 = emitc.literal "0" : i32
   %p0 = emitc.literal "M_PI" : f32
 
-  %2 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> i32
-  %3 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f32
-  emitc.assign %s0 : i32 to %2 : i32
-  emitc.assign %p0 : f32 to %3 : f32
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %1 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  %2 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %3 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  emitc.assign %s0 : i32 to %2 : !emitc.lvalue<i32>
+  emitc.assign %p0 : f32 to %3 : !emitc.lvalue<f32>
   emitc.for %iter = %start to %stop step %step {
-    %sn = emitc.call_opaque "add"(%2, %iter) : (i32, index) -> i32
-    %pn = emitc.call_opaque "mul"(%3, %iter) : (f32, index) -> f32
-    emitc.assign %sn : i32 to %2 : i32
-    emitc.assign %pn : f32 to %3 : f32
+    %4 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+    %sn = emitc.call_opaque "add"(%4, %iter) : (i32, index) -> i32
+    %5 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+    %pn = emitc.call_opaque "mul"(%5, %iter) : (f32, index) -> f32
+    emitc.assign %sn : i32 to %2 : !emitc.lvalue<i32>
+    emitc.assign %pn : f32 to %3 : !emitc.lvalue<f32>
     emitc.yield
   }
+  %6 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+  emitc.assign %6 : i32 to %0 : !emitc.lvalue<i32>
+  %7 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+  emitc.assign %7 : f32 to %1 : !emitc.lvalue<f32>
 
   return
 }
diff --git a/mlir/test/Target/Cpp/global.mlir b/mlir/test/Target/Cpp/global.mlir
index f0d92e862ae32..32eb8c6cf6f87 100644
--- a/mlir/test/Target/Cpp/global.mlir
+++ b/mlir/test/Target/Cpp/global.mlir
@@ -1,38 +1,100 @@
-// RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s
-// RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s
+// RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s -check-prefix=CPP-DEFAULT
+// RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s -check-prefix=CPP-DECLTOP
 
 emitc.global extern @decl : i8
-// CHECK: extern int8_t decl;
+// CPP-DEFAULT: extern int8_t decl;
+// CPP-DECLTOP: extern int8_t decl;
 
 emitc.global @uninit : i32
-// CHECK: int32_t uninit;
+// CPP-DEFAULT: int32_t uninit;
+// CPP-DECLTOP: int32_t uninit;
 
 emitc.global @myglobal_int : i32 = 4
-// CHECK: int32_t myglobal_int = 4;
+// CPP-DEFAULT: int32_t myglobal_int = 4;
+// CPP-DECLTOP: int32_t myglobal_int = 4;
 
 emitc.global @myglobal : !emitc.array<2xf32> = dense<4.000000e+00>
-// CHECK: float myglobal[2] = {4.000000000e+00f, 4.000000000e+00f};
+// CPP-DEFAULT: float myglobal[2] = {4.000000000e+00f, 4.000000000e+00f};
+// CPP-DECLTOP: float myglobal[2] = {4.000000000e+00f, 4.000000000e+00f};
 
 emitc.global const @myconstant : !emitc.array<2xi16> = dense<2>
-// CHECK: const int16_t myconstant[2] = {2, 2};
+// CPP-DEFAULT: const int16_t myconstant[2] = {2, 2};
+// CPP-DECLTOP: const int16_t myconstant[2] = {2, 2};
 
 emitc.global extern const @extern_constant : !emitc.array<2xi16>
-// CHECK: extern const int16_t extern_constant[2];
+// CPP-DEFAULT: extern const int16_t extern_constant[2];
+// CPP-DECLTOP: extern const int16_t extern_constant[2];
 
 emitc.global static @static_var : f32
-// CHECK: static float static_var;
+// CPP-DEFAULT: static float static_var;
+// CPP-DECLTOP: static float static_var;
 
 emitc.global static @static_const : f32 = 3.0
-// CHECK: static float static_const = 3.000000000e+00f;
+// CPP-DEFAULT: static float static_const = 3.000000000e+00f;
+// CPP-DECLTOP: static float static_const = 3.000000000e+00f;
 
 emitc.global @opaque_init : !emitc.opaque<"char"> = #emitc.opaque<"CHAR_MIN">
-// CHECK: char opaque_init = CHAR_MIN;
+// CPP-DEFAULT: char opaque_init = CHAR_MIN;
+// CPP-DECLTOP: char opaque_init = CHAR_MIN;
 
-func.func @use_global(%i: index) -> f32 {
+func.func @use_global_scalar_read() -> i32 {
+  %0 = emitc.get_global @myglobal_int : !emitc.lvalue<i32>
+  %1 = emitc.lvalue_load %0 : !emitc.lvalue<i32>
+  return %1 : i32
+}
+// CPP-DEFAULT-LABEL: int32_t use_global_scalar_read()
+// CPP-DEFAULT-NEXT: int32_t [[V1:[^ ]*]] = myglobal_int;
+// CPP-DEFAULT-NEXT: return [[V1]];
+
+// CPP-DECLTOP-LABEL: int32_t use_global_scalar_read()
+// CPP-DECLTOP-NEXT: int32_t [[V1:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[V1]] = myglobal_int;
+// CPP-DECLTOP-NEXT: return [[V1]];
+
+func.func @use_global_scalar_write(%arg0 : i32) {
+  %0 = emitc.get_global @myglobal_int : !emitc.lvalue<i32>
+  emitc.assign %arg0 : i32 to %0 : !emitc.lvalue<i32> 
+  return
+}
+// CPP-DEFAULT-LABEL: void use_global_scalar_write
+// CPP-DEFAULT-SAME: (int32_t [[V1:.*]])
+// CPP-DEFAULT-NEXT: myglobal_int = [[V1]];
+// CPP-DEFAULT-NEXT: return;
+
+// CPP-DECLTOP-LABEL: void use_global_scalar_write
+// CPP-DECLTOP-SAME: (int32_t [[V1:.*]])
+// CPP-DECLTOP-NEXT: myglobal_int = [[V1]];
+// CPP-DECLTOP-NEXT: return;
+
+func.func @use_global_array_read(%i: index) -> f32 {
   %0 = emitc.get_global @myglobal : !emitc.array<2xf32>
-  %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> f32
-  return %1 : f32
-  // CHECK-LABEL: use_global
-  // CHECK-SAME: (size_t [[V1:.*]])
-  // CHECK:   return myglobal[[[V1]]];
+  %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> !emitc.lvalue<f32>
+  %2 = emitc.lvalue_load %1 : <f32>
+  return %2 : f32
 }
+// CPP-DEFAULT-LABEL: float use_global_array_read
+// CPP-DEFAULT-SAME: (size_t [[V1:.*]])
+// CPP-DEFAULT-NEXT: float [[V2:[^ ]*]] = myglobal[[[V1]]];
+// CPP-DEFAULT-NEXT: return [[V2]];
+
+// CPP-DECLTOP-LABEL: float use_global_array_read
+// CPP-DECLTOP-SAME: (size_t [[V1:.*]])
+// CPP-DECLTOP-NEXT: float [[V2:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[V2]] = myglobal[[[V1]]];
+// CPP-DECLTOP-NEXT: return [[V2]];
+
+func.func @use_global_array_write(%i: index, %val : f32) {
+  %0 = emitc.get_global @myglobal : !emitc.array<2xf32>
+  %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> !emitc.lvalue<f32>
+  emitc.assign %val : f32 to %1 : !emitc.lvalue<f32> 
+  return
+}
+// CPP-DEFAULT-LABEL: void use_global_array_write
+// CPP-DEFAULT-SAME: (size_t [[V1:.*]], float [[V2:.*]])
+// CPP-DEFAULT-NEXT: myglobal[[[V1]]] = [[V2]];
+// CPP-DEFAULT-NEXT: return;
+
+// CPP-DECLTOP-LABEL: void use_global_array_write
+// CPP-DECLTOP-SAME: (size_t [[V1:.*]], float [[V2:.*]])
+// CPP-DECLTOP-NEXT: myglobal[[[V1]]] = [[V2]];
+// CPP-DECLTOP-NEXT: return;
diff --git a/mlir/test/Target/Cpp/if.mlir b/mlir/test/Target/Cpp/if.mlir
index 7b0e2da85d0eb..d3b792192c8b1 100644
--- a/mlir/test/Target/Cpp/if.mlir
+++ b/mlir/test/Target/Cpp/if.mlir
@@ -50,18 +50,18 @@ func.func @test_if_else(%arg0: i1, %arg1: f32) {
 
 func.func @test_if_yield(%arg0: i1, %arg1: f32) {
   %0 = "emitc.constant"() <{value = 0 : i8}> : () -> i8
-  %x = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> i32
-  %y = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> f64
+  %x = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %y = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f64>
   emitc.if %arg0 {
     %1 = emitc.call_opaque "func_true_1"(%arg1) : (f32) -> i32
     %2 = emitc.call_opaque "func_true_2"(%arg1) : (f32) -> f64
-    emitc.assign %1 : i32 to %x : i32
-    emitc.assign %2 : f64 to %y : f64
+    emitc.assign %1 : i32 to %x : !emitc.lvalue<i32>
+    emitc.assign %2 : f64 to %y : !emitc.lvalue<f64>
   } else {
     %1 = emitc.call_opaque "func_false_1"(%arg1) : (f32) -> i32
     %2 = emitc.call_opaque "func_false_2"(%arg1) : (f32) -> f64
-    emitc.assign %1 : i32 to %x : i32
-    emitc.assign %2 : f64 to %y : f64
+    emitc.assign %1 : i32 to %x : !emitc.lvalue<i32>
+    emitc.assign %2 : f64 to %y : !emitc.lvalue<f64>
   }
   return
 }
diff --git a/mlir/test/Target/Cpp/invalid.mlir b/mlir/test/Target/Cpp/invalid.mlir
index 513371a09cde1..14fd0cd56170b 100644
--- a/mlir/test/Target/Cpp/invalid.mlir
+++ b/mlir/test/Target/Cpp/invalid.mlir
@@ -82,6 +82,6 @@ func.func @array_as_result(%arg: !emitc.array<4xi8>) -> (!emitc.array<4xi8>) {
 // -----
 func.func @ptr_to_array() {
   // expected-error at +1 {{cannot emit pointer to array type '!emitc.ptr<!emitc.array<9xi16>>'}}
-  %v = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.ptr<!emitc.array<9xi16>>
+  %v = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.lvalue<!emitc.ptr<!emitc.array<9xi16>>>
   return
 }
diff --git a/mlir/test/Target/Cpp/lvalue.mlir b/mlir/test/Target/Cpp/lvalue.mlir
new file mode 100644
index 0000000000000..ce76dd7a7cfeb
--- /dev/null
+++ b/mlir/test/Target/Cpp/lvalue.mlir
@@ -0,0 +1,17 @@
+// RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s
+
+// CHECK: int32_t lvalue_variables(
+emitc.func @lvalue_variables(%v1: i32, %v2: i32) -> i32 {
+  %val = emitc.mul %v1, %v2 : (i32, i32) -> i32
+  %variable = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32> // alloc effect
+  emitc.assign %val : i32 to %variable : !emitc.lvalue<i32> // write effect
+  %addr = emitc.apply "&"(%variable) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  emitc.call @zero (%addr) : (!emitc.ptr<i32>) -> ()
+  %updated_val = emitc.lvalue_load %variable : !emitc.lvalue<i32> // read effect, (noop in emitter?)
+  %neg_one = "emitc.constant"() {value = -1 : i32} : () -> i32
+  emitc.assign %neg_one : i32 to %variable : !emitc.lvalue<i32> // invalidates %updated_val
+  emitc.return %updated_val : i32
+  // dealloc effect through automatic allocation scope
+}
+
+emitc.func @zero(%arg0: !emitc.ptr<i32>) attributes {specifiers = ["extern"]}
\ No newline at end of file
diff --git a/mlir/test/Target/Cpp/subscript.mlir b/mlir/test/Target/Cpp/subscript.mlir
index 0b388953c80d3..b5c94c146712e 100644
--- a/mlir/test/Target/Cpp/subscript.mlir
+++ b/mlir/test/Target/Cpp/subscript.mlir
@@ -1,35 +1,59 @@
-// RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s
-// RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s
+// RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s -check-prefix=CPP-DEFAULT
+// RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s -check-prefix=CPP-DECLTOP
 
 func.func @load_store_array(%arg0: !emitc.array<4x8xf32>, %arg1: !emitc.array<3x5xf32>, %arg2: index, %arg3: index) {
-  %0 = emitc.subscript %arg0[%arg2, %arg3] : (!emitc.array<4x8xf32>, index, index) -> f32
-  %1 = emitc.subscript %arg1[%arg2, %arg3] : (!emitc.array<3x5xf32>, index, index) -> f32
-  emitc.assign %0 : f32 to %1 : f32
+  %0 = emitc.subscript %arg0[%arg2, %arg3] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<f32>
+  %1 = emitc.subscript %arg1[%arg2, %arg3] : (!emitc.array<3x5xf32>, index, index) -> !emitc.lvalue<f32>
+  %2 = emitc.lvalue_load %0 : <f32>
+  emitc.assign %2 : f32 to %1 : !emitc.lvalue<f32>
   return
 }
-// CHECK: void load_store_array(float [[ARR1:[^ ]*]][4][8], float [[ARR2:[^ ]*]][3][5],
-// CHECK-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
-// CHECK-NEXT: [[ARR2]][[[I]]][[[J]]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DEFAULT: void load_store_array(float [[ARR1:[^ ]*]][4][8], float [[ARR2:[^ ]*]][3][5],
+// CPP-DEFAULT-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
+// CPP-DEFAULT-NEXT: float [[VAL:[^ ]*]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DEFAULT-NEXT: [[ARR2]][[[I]]][[[J]]] = [[VAL]];
+
+// CPP-DECLTOP: void load_store_array(float [[ARR1:[^ ]*]][4][8], float [[ARR2:[^ ]*]][3][5],
+// CPP-DECLTOP-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
+// CPP-DECLTOP-NEXT: float [[VAL:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[VAL]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DECLTOP-NEXT: [[ARR2]][[[I]]][[[J]]] = [[VAL]];
 
 func.func @load_store_pointer(%arg0: !emitc.ptr<f32>, %arg1: !emitc.ptr<f32>, %arg2: index, %arg3: index) {
-  %0 = emitc.subscript %arg0[%arg2] : (!emitc.ptr<f32>, index) -> f32
-  %1 = emitc.subscript %arg1[%arg3] : (!emitc.ptr<f32>, index) -> f32
-  emitc.assign %0 : f32 to %1 : f32
+  %0 = emitc.subscript %arg0[%arg2] : (!emitc.ptr<f32>, index) -> !emitc.lvalue<f32>
+  %1 = emitc.subscript %arg1[%arg3] : (!emitc.ptr<f32>, index) -> !emitc.lvalue<f32>
+  %2 = emitc.lvalue_load %0 : <f32>
+  emitc.assign %2 : f32 to %1 : <f32>
   return
 }
-// CHECK: void load_store_pointer(float* [[PTR1:[^ ]*]], float* [[PTR2:[^ ]*]],
-// CHECK-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
-// CHECK-NEXT: [[PTR2]][[[J]]] = [[PTR1]][[[I]]];
+// CPP-DEFAULT: void load_store_pointer(float* [[PTR1:[^ ]*]], float* [[PTR2:[^ ]*]],
+// CPP-DEFAULT-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
+// CPP-DEFAULT-NEXT: float [[VAL:[^ ]*]] = [[PTR1]][[[I]]];
+// CPP-DEFAULT-NEXT: [[PTR2]][[[J]]] = [[VAL]];
+
+// CPP-DECLTOP: void load_store_pointer(float* [[PTR1:[^ ]*]], float* [[PTR2:[^ ]*]],
+// CPP-DECLTOP-SAME:            size_t [[I:[^ ]*]], size_t [[J:[^ ]*]])
+// CPP-DECLTOP-NEXT: float [[VAL:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[VAL]] = [[PTR1]][[[I]]];
+// CPP-DECLTOP-NEXT: [[PTR2]][[[J]]] = [[VAL]];
 
 func.func @load_store_opaque(%arg0: !emitc.opaque<"std::map<char, int>">, %arg1: !emitc.opaque<"std::map<char, int>">, %arg2: !emitc.opaque<"char">, %arg3: !emitc.opaque<"char">) {
-  %0 = emitc.subscript %arg0[%arg2] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.opaque<"int">
-  %1 = emitc.subscript %arg1[%arg3] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.opaque<"int">
-  emitc.assign %0 : !emitc.opaque<"int"> to %1 : !emitc.opaque<"int">
+  %0 = emitc.subscript %arg0[%arg2] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.lvalue<!emitc.opaque<"int">>
+  %1 = emitc.subscript %arg1[%arg3] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.lvalue<!emitc.opaque<"int">>
+  %2 = emitc.lvalue_load %0 : <!emitc.opaque<"int">>
+  emitc.assign %2 : !emitc.opaque<"int"> to %1 : <!emitc.opaque<"int">>
   return
 }
-// CHECK: void load_store_opaque(std::map<char, int> [[MAP1:[^ ]*]], std::map<char, int> [[MAP2:[^ ]*]],
-// CHECK-SAME:            char [[I:[^ ]*]], char [[J:[^ ]*]])
-// CHECK-NEXT: [[MAP2]][[[J]]] = [[MAP1]][[[I]]];
+// CPP-DEFAULT: void load_store_opaque(std::map<char, int> [[MAP1:[^ ]*]], std::map<char, int> [[MAP2:[^ ]*]],
+// CPP-DEFAULT-SAME:            char [[I:[^ ]*]], char [[J:[^ ]*]])
+// CPP-DEFAULT-NEXT: int [[VAL:[^ ]*]] = [[MAP1]][[[I]]];
+// CPP-DEFAULT-NEXT: [[MAP2]][[[J]]] = [[VAL]];
+
+// CPP-DECLTOP: void load_store_opaque(std::map<char, int> [[MAP1:[^ ]*]], std::map<char, int> [[MAP2:[^ ]*]],
+// CPP-DECLTOP-SAME:            char [[I:[^ ]*]], char [[J:[^ ]*]])
+// CPP-DECLTOP-NEXT: int [[VAL:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[VAL]] = [[MAP1]][[[I]]];
+// CPP-DECLTOP-NEXT: [[MAP2]][[[J]]] = [[VAL]];
 
 emitc.func @func1(%arg0 : f32) {
   emitc.return
@@ -37,16 +61,38 @@ emitc.func @func1(%arg0 : f32) {
 
 emitc.func @call_arg(%arg0: !emitc.array<4x8xf32>, %i: i32, %j: i16,
                      %k: i8) {
-  %0 = emitc.subscript %arg0[%i, %j] : (!emitc.array<4x8xf32>, i32, i16) -> f32
-  %1 = emitc.subscript %arg0[%j, %k] : (!emitc.array<4x8xf32>, i16, i8) -> f32
+  %0 = emitc.subscript %arg0[%i, %j] : (!emitc.array<4x8xf32>, i32, i16) -> !emitc.lvalue<f32>
+  %1 = emitc.subscript %arg0[%j, %k] : (!emitc.array<4x8xf32>, i16, i8) -> !emitc.lvalue<f32>
 
-  emitc.call @func1 (%0) : (f32) -> ()
-  emitc.call_opaque "func2" (%1) : (f32) -> ()
-  emitc.call_opaque "func3" (%0, %1) { args = [1 : index, 0 : index] } : (f32, f32) -> ()
+  %2 = emitc.lvalue_load %0 : <f32>
+  emitc.call @func1 (%2) : (f32) -> ()
+  %3 = emitc.lvalue_load %1 : <f32>
+  emitc.call_opaque "func2" (%3) : (f32) -> ()
+  %4 = emitc.lvalue_load %0 : <f32>
+  %5 = emitc.lvalue_load %1 : <f32>
+  emitc.call_opaque "func3" (%4, %5) { args = [1 : index, 0 : index] } : (f32, f32) -> ()
   emitc.return
 }
-// CHECK: void call_arg(float [[ARR1:[^ ]*]][4][8], int32_t [[I:[^ ]*]],
-// CHECK-SAME:          int16_t [[J:[^ ]*]], int8_t [[K:[^ ]*]])
-// CHECK-NEXT: func1([[ARR1]][[[I]]][[[J]]]);
-// CHECK-NEXT: func2([[ARR1]][[[J]]][[[K]]]);
-// CHECK-NEXT: func3([[ARR1]][[[J]]][[[K]]], [[ARR1]][[[I]]][[[J]]]);
+// CPP-DEFAULT: void call_arg(float [[ARR1:[^ ]*]][4][8], int32_t [[I:[^ ]*]],
+// CPP-DEFAULT-SAME:          int16_t [[J:[^ ]*]], int8_t [[K:[^ ]*]])
+// CPP-DEFAULT-NEXT: float [[VAL0:[^ ]*]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DEFAULT-NEXT: func1([[VAL0]]);
+// CPP-DEFAULT-NEXT: float [[VAL1:[^ ]*]] = [[ARR1]][[[J]]][[[K]]];
+// CPP-DEFAULT-NEXT: func2([[VAL1]]);
+// CPP-DEFAULT-NEXT: float [[VAL2:[^ ]*]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DEFAULT-NEXT: float [[VAL3:[^ ]*]] = [[ARR1]][[[J]]][[[K]]];
+// CPP-DEFAULT-NEXT: func3([[VAL3]], [[VAL2]]);
+
+// CPP-DECLTOP: void call_arg(float [[ARR1:[^ ]*]][4][8], int32_t [[I:[^ ]*]],
+// CPP-DECLTOP-SAME:          int16_t [[J:[^ ]*]], int8_t [[K:[^ ]*]])
+// CPP-DECLTOP-NEXT: float [[VAL0:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[VAL1:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[VAL2:[^ ]*]];
+// CPP-DECLTOP-NEXT: float [[VAL3:[^ ]*]];
+// CPP-DECLTOP-NEXT: [[VAL0]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DECLTOP-NEXT: func1([[VAL0]]);
+// CPP-DECLTOP-NEXT: [[VAL1]] = [[ARR1]][[[J]]][[[K]]];
+// CPP-DECLTOP-NEXT: func2([[VAL1]]);
+// CPP-DECLTOP-NEXT: [[VAL2]] = [[ARR1]][[[I]]][[[J]]];
+// CPP-DECLTOP-NEXT: [[VAL3]] = [[ARR1]][[[J]]][[[K]]];
+// CPP-DECLTOP-NEXT: func3([[VAL3]], [[VAL2]]);
diff --git a/mlir/test/Target/Cpp/variable.mlir b/mlir/test/Target/Cpp/variable.mlir
index 126dd384b47a2..a26d724127cf2 100644
--- a/mlir/test/Target/Cpp/variable.mlir
+++ b/mlir/test/Target/Cpp/variable.mlir
@@ -2,13 +2,13 @@
 // RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s -check-prefix=CPP-DECLTOP
 
 func.func @emitc_variable() {
-  %c0 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i32
-  %c1 = "emitc.variable"(){value = 42 : i32} : () -> i32
-  %c2 = "emitc.variable"(){value = -1 : i32} : () -> i32
-  %c3 = "emitc.variable"(){value = -1 : si8} : () -> si8
-  %c4 = "emitc.variable"(){value = 255 : ui8} : () -> ui8
-  %c5 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.ptr<i32>
-  %c6 = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.ptr<i32>
+  %c0 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
+  %c1 = "emitc.variable"(){value = 42 : i32} : () -> !emitc.lvalue<i32>
+  %c2 = "emitc.variable"(){value = -1 : i32} : () -> !emitc.lvalue<i32>
+  %c3 = "emitc.variable"(){value = -1 : si8} : () -> !emitc.lvalue<si8>
+  %c4 = "emitc.variable"(){value = 255 : ui8} : () -> !emitc.lvalue<ui8>
+  %c5 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<!emitc.ptr<i32>>
+  %c6 = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.lvalue<!emitc.ptr<i32>>
   %c7 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.array<3x7xi32>
   %c8 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.array<5x!emitc.ptr<i8>>
   return
@@ -41,3 +41,5 @@ func.func @emitc_variable() {
 // CPP-DECLTOP-NEXT: [[V4]] = 255;
 // CPP-DECLTOP-NEXT: ;
 // CPP-DECLTOP-NEXT: [[V6]] = NULL;
+// CPP-DECLTOP-NEXT: ;
+// CPP-DECLTOP-NEXT: ;

>From aede30346e49f088bfa5f2aa8b1a15ff2d263ef4 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 11:43:49 +0000
Subject: [PATCH 02/13] Add check lines

---
 mlir/test/Target/Cpp/lvalue.mlir | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/mlir/test/Target/Cpp/lvalue.mlir b/mlir/test/Target/Cpp/lvalue.mlir
index ce76dd7a7cfeb..5ef7fb2763246 100644
--- a/mlir/test/Target/Cpp/lvalue.mlir
+++ b/mlir/test/Target/Cpp/lvalue.mlir
@@ -1,17 +1,28 @@
 // RUN: mlir-translate -mlir-to-cpp %s | FileCheck %s
 
-// CHECK: int32_t lvalue_variables(
 emitc.func @lvalue_variables(%v1: i32, %v2: i32) -> i32 {
   %val = emitc.mul %v1, %v2 : (i32, i32) -> i32
-  %variable = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32> // alloc effect
-  emitc.assign %val : i32 to %variable : !emitc.lvalue<i32> // write effect
+  %variable = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32> 
+  emitc.assign %val : i32 to %variable : !emitc.lvalue<i32>
   %addr = emitc.apply "&"(%variable) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   emitc.call @zero (%addr) : (!emitc.ptr<i32>) -> ()
-  %updated_val = emitc.lvalue_load %variable : !emitc.lvalue<i32> // read effect, (noop in emitter?)
+  %updated_val = emitc.lvalue_load %variable : !emitc.lvalue<i32>
   %neg_one = "emitc.constant"() {value = -1 : i32} : () -> i32
-  emitc.assign %neg_one : i32 to %variable : !emitc.lvalue<i32> // invalidates %updated_val
+  emitc.assign %neg_one : i32 to %variable : !emitc.lvalue<i32>
   emitc.return %updated_val : i32
-  // dealloc effect through automatic allocation scope
 }
+// CHECK-LABEL: int32_t lvalue_variables(
+// CHECK-SAME: int32_t [[V1:[^ ]*]], int32_t [[V2:[^ ]*]])
+// CHECK-NEXT: int32_t [[VAL:[^ ]*]] = [[V1]] * [[V2]];
+// CHECK-NEXT: int32_t [[VAR:[^ ]*]];
+// CHECK-NEXT: [[VAR]] = [[VAL]];
+// CHECK-NEXT: int32_t* [[VAR_PTR:[^ ]*]] = &[[VAR]];
+// CHECK-NEXT: zero([[VAR_PTR]]);
+// CHECK-NEXT: int32_t [[VAR_LOAD:[^ ]*]] = [[VAR]]; 
+// CHECK-NEXT: int32_t [[NEG_ONE:[^ ]*]] = -1; 
+// CHECK-NEXT: [[VAR]] = [[NEG_ONE]];
+// CHECK-NEXT: return [[VAR_LOAD]];
 
-emitc.func @zero(%arg0: !emitc.ptr<i32>) attributes {specifiers = ["extern"]}
\ No newline at end of file
+
+emitc.func @zero(%arg0: !emitc.ptr<i32>) attributes {specifiers = ["extern"]}
+// CHECK-LABEL: extern void zero(int32_t*);

>From 1652adaf953ecb41aab0fdb153ab0d9385f5cce5 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 13:39:13 +0000
Subject: [PATCH 03/13] Add memory effects

---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index 30a626a49a869..0f85e15352f41 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -843,7 +843,8 @@ def EmitC_LValueLoadOp : EmitC_Op<"lvalue_load", [
   let summary = "load an lvalue by assigning it to a local variable";
   let description = [{}];
 
-  let arguments = (ins EmitC_LValueType:$operand);
+  let arguments = (ins 
+      Res<EmitC_LValueType, "", [MemRead<DefaultResource, 0, FullEffect>]>:$operand);
   let results = (outs AnyType:$result);
 
   let assemblyFormat = "$operand attr-dict `:` type($operand)"; 
@@ -1023,7 +1024,8 @@ def EmitC_VariableOp : EmitC_Op<"variable", []> {
   }];
 
   let arguments = (ins EmitC_OpaqueOrTypedAttr:$value);
-  let results = (outs AnyTypeOf<[EmitC_ArrayType, EmitC_LValueType]>);
+  let results = (outs Res<AnyTypeOf<[EmitC_ArrayType, EmitC_LValueType]>, "",
+                          [MemAlloc<DefaultResource, 0, FullEffect>]>:$memref);
 
   let hasVerifier = 1;
 }
@@ -1151,7 +1153,9 @@ def EmitC_AssignOp : EmitC_Op<"assign", []> {
     ```
   }];
 
-  let arguments = (ins EmitC_LValueType:$var, EmitCType:$value);
+  let arguments = (ins 
+      Res<EmitC_LValueType, "", [MemWrite<DefaultResource, 1, FullEffect>]>:$var,
+      Res<EmitCType, "", [MemRead<DefaultResource, 0, FullEffect>]>:$value);
   let results = (outs);
 
   let hasVerifier = 1;

>From 08add09a0c60fc3b494c17aa5025c660856b6ac8 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 13:50:55 +0000
Subject: [PATCH 04/13] Disallow lvalues as block arguments

---
 mlir/lib/Target/Cpp/TranslateToCpp.cpp            |  4 ++--
 .../Cpp/invalid_declare_variables_at_top.mlir     | 15 +++++++++++++--
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index 66808289e79f7..cf7a44d75bd8e 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -985,9 +985,9 @@ static LogicalResult printFunctionBody(CppEmitter &emitter,
       if (emitter.hasValueInScope(arg))
         return functionOp->emitOpError(" block argument #")
                << arg.getArgNumber() << " is out of scope";
-      if (isa<ArrayType>(arg.getType()))
+      if (isa<ArrayType, LValueType>(arg.getType()))
         return functionOp->emitOpError("cannot emit block argument #")
-               << arg.getArgNumber() << " with array type";
+               << arg.getArgNumber() << " with type " << arg.getType();
       if (failed(
               emitter.emitType(block.getParentOp()->getLoc(), arg.getType()))) {
         return failure();
diff --git a/mlir/test/Target/Cpp/invalid_declare_variables_at_top.mlir b/mlir/test/Target/Cpp/invalid_declare_variables_at_top.mlir
index 844fe03bad4ab..8b87113e6d960 100644
--- a/mlir/test/Target/Cpp/invalid_declare_variables_at_top.mlir
+++ b/mlir/test/Target/Cpp/invalid_declare_variables_at_top.mlir
@@ -1,9 +1,20 @@
 // RUN: mlir-translate -split-input-file -declare-variables-at-top -mlir-to-cpp -verify-diagnostics %s
 
-// expected-error at +1 {{'func.func' op cannot emit block argument #0 with array type}}
+// expected-error at +1 {{'func.func' op cannot emit block argument #0 with type '!emitc.array<4xi8>'}}
 func.func @array_as_block_argument(!emitc.array<4xi8>) {
 ^bb0(%arg0 : !emitc.array<4xi8>):
   cf.br ^bb1(%arg0 : !emitc.array<4xi8>)
 ^bb1(%a : !emitc.array<4xi8>):
-   return
+  return
+}
+
+// -----
+
+// expected-error at +1 {{'emitc.func' op cannot emit block argument #0 with type '!emitc.lvalue<i32>'}}
+emitc.func @lvalue_as_block_argument() {
+^bb0:
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  cf.br ^bb1(%0 : !emitc.lvalue<i32>)
+^bb1(%a : !emitc.lvalue<i32>):
+  emitc.return
 }

>From 4aa7f77e883be9e898190fde4bac0b694e82912e Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 14:04:48 +0000
Subject: [PATCH 05/13] Fix line endings

---
 mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
index 554d9d79f1700..59a090a5fc65f 100644
--- a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
+++ b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
@@ -216,4 +216,4 @@ void SCFToEmitCPass::runOnOperation() {
   if (failed(
           applyPartialConversion(getOperation(), target, std::move(patterns))))
     signalPassFailure();
-}
\ No newline at end of file
+}

>From e50266cb5e8e8513fb61e2a8bbca019bab9fcf9f Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 16:32:29 +0200
Subject: [PATCH 06/13] Apply suggestions from code review

Co-authored-by: Matthias Gehre <matthias.gehre at amd.com>
---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index 0f85e15352f41..151cf9b2e1ead 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -840,7 +840,7 @@ def EmitC_LValueLoadOp : EmitC_Op<"lvalue_load", [
                   "operand", "result",
                   "::llvm::cast<LValueType>($_self).getValue()">
 ]> {
-  let summary = "load an lvalue by assigning it to a local variable";
+  let summary = "Load an lvalue into an SSA value.";
   let description = [{}];
 
   let arguments = (ins 

>From f06df1773d477fe205c39fbfc53abfec85257740 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Tue, 11 Jun 2024 14:46:17 +0000
Subject: [PATCH 07/13] Review comments

---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td      | 10 +++++++---
 mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td |  8 ++++----
 mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp    |  4 ++--
 mlir/lib/Dialect/EmitC/IR/EmitC.cpp              | 12 ++++++------
 mlir/lib/Target/Cpp/TranslateToCpp.cpp           |  2 +-
 5 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index 151cf9b2e1ead..edc533f6159cf 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -838,10 +838,14 @@ def EmitC_LogicalOrOp : EmitC_BinaryOp<"logical_or", [CExpression]> {
 def EmitC_LValueLoadOp : EmitC_Op<"lvalue_load", [
   TypesMatchWith<"result type matches value type of 'operand'",
                   "operand", "result",
-                  "::llvm::cast<LValueType>($_self).getValue()">
+                  "::llvm::cast<LValueType>($_self).getValueType()">
 ]> {
   let summary = "Load an lvalue into an SSA value.";
-  let description = [{}];
+  let description = [{
+    This operation loads the content of a modifiable lvalue into an SSA value. 
+    Modifications of the lvalue executed after the load are not observable on 
+    the produced value.
+  }];
 
   let arguments = (ins 
       Res<EmitC_LValueType, "", [MemRead<DefaultResource, 0, FullEffect>]>:$operand);
@@ -1155,7 +1159,7 @@ def EmitC_AssignOp : EmitC_Op<"assign", []> {
 
   let arguments = (ins 
       Res<EmitC_LValueType, "", [MemWrite<DefaultResource, 1, FullEffect>]>:$var,
-      Res<EmitCType, "", [MemRead<DefaultResource, 0, FullEffect>]>:$value);
+      EmitCType:$value);
   let results = (outs);
 
   let hasVerifier = 1;
diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
index fc795962a3e5b..f420d2faa364a 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitCTypes.td
@@ -90,13 +90,13 @@ def EmitC_LValueType : EmitC_Type<"LValue", "lvalue"> {
     Values of this type can be assigned to and their address can be taken.
   }];
 
-  let parameters = (ins "Type":$value);
+  let parameters = (ins "Type":$valueType);
   let builders = [
-    TypeBuilderWithInferredContext<(ins "Type":$value), [{
-      return $_get(value.getContext(), value);
+    TypeBuilderWithInferredContext<(ins "Type":$valueType), [{
+      return $_get(valueType.getContext(), valueType);
     }]>
   ];
-  let assemblyFormat = "`<` qualified($value) `>`";
+  let assemblyFormat = "`<` qualified($valueType) `>`";
   let genVerifyDecl = 1;
 }
 
diff --git a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
index 59a090a5fc65f..adcbf9009d041 100644
--- a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
+++ b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
@@ -84,7 +84,7 @@ static void assignValues(ValueRange values, SmallVector<Value> &variables,
 SmallVector<Value> loadValues(const SmallVector<Value> &variables,
                               PatternRewriter &rewriter, Location loc) {
   return llvm::map_to_vector<>(variables, [&](Value var) {
-    Type type = cast<emitc::LValueType>(var.getType()).getValue();
+    Type type = cast<emitc::LValueType>(var.getType()).getValueType();
     return rewriter.create<emitc::LValueLoadOp>(loc, type, var).getResult();
   });
 }
@@ -138,7 +138,7 @@ LogicalResult ForLowering::matchAndRewrite(ForOp forOp,
   lowerYield(resultVariables, rewriter,
              cast<scf::YieldOp>(loweredBody->getTerminator()));
 
-  // Copy iterArgs into results after the for loop.
+  // Load variables into SSA values after the for loop.
   SmallVector<Value> resultValues = loadValues(resultVariables, rewriter, loc);
 
   rewriter.replaceOp(forOp, resultValues);
diff --git a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
index 90fca1c2bb0b2..ebedfa3696041 100644
--- a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
+++ b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
@@ -144,7 +144,7 @@ static LogicalResult verifyInitializationAttribute(Operation *op,
 
   Type resultType = op->getResult(0).getType();
   if (auto lType = dyn_cast<LValueType>(resultType))
-    resultType = lType.getValue();
+    resultType = lType.getValueType();
   Type attrType = cast<TypedAttr>(value).getType();
 
   if (resultType != attrType)
@@ -221,7 +221,7 @@ LogicalResult emitc::AssignOp::verify() {
     return emitOpError() << "cannot assign to block argument";
 
   Type valueType = getValue().getType();
-  Type variableType = variable.getType().getValue();
+  Type variableType = variable.getType().getValueType();
   if (variableType != valueType)
     return emitOpError() << "requires value's type (" << valueType
                          << ") to match variable's type (" << variableType
@@ -853,7 +853,7 @@ LogicalResult emitc::SubscriptOp::verify() {
     }
     // Check element type.
     Type elementType = arrayType.getElementType();
-    Type resultType = getType().getValue();
+    Type resultType = getType().getValueType();
     if (elementType != resultType) {
       return emitOpError() << "on array operand requires element type ("
                            << elementType << ") and result type (" << resultType
@@ -880,7 +880,7 @@ LogicalResult emitc::SubscriptOp::verify() {
     }
     // Check pointee type.
     Type pointeeType = pointerType.getPointee();
-    Type resultType = getType().getValue();
+    Type resultType = getType().getValueType();
     if (pointeeType != resultType) {
       return emitOpError() << "on pointer operand requires pointee type ("
                            << pointeeType << ") and result type (" << resultType
@@ -1135,9 +1135,9 @@ GetGlobalOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
 
   // global has non-array type
   auto lvalueType = dyn_cast<LValueType>(resultType);
-  if (!lvalueType || lvalueType.getValue() != globalType)
+  if (!lvalueType || lvalueType.getValueType() != globalType)
     return emitOpError("on non-array type expects result inner type ")
-           << lvalueType.getValue() << " to match type " << globalType
+           << lvalueType.getValueType() << " to match type " << globalType
            << " of the global @" << getName();
   return success();
 }
diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index cf7a44d75bd8e..0982c21271444 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -1615,7 +1615,7 @@ LogicalResult CppEmitter::emitType(Location loc, Type type) {
     return success();
   }
   if (auto lType = dyn_cast<emitc::LValueType>(type))
-    return emitType(loc, lType.getValue());
+    return emitType(loc, lType.getValueType());
   if (auto pType = dyn_cast<emitc::PointerType>(type)) {
     if (isa<ArrayType>(pType.getPointee()))
       return emitError(loc, "cannot emit pointer to array type ") << type;

>From 78f5a5ca3762cdc2eeec7a080e922249b59f8cc2 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Wed, 12 Jun 2024 08:12:56 +0000
Subject: [PATCH 08/13] Rename lvalue_load to load

---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td      |  2 +-
 .../Conversion/MemRefToEmitC/MemRefToEmitC.cpp   |  2 +-
 mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp    |  2 +-
 mlir/lib/Target/Cpp/TranslateToCpp.cpp           | 11 +++++------
 .../MemRefToEmitC/memref-to-emitc.mlir           |  2 +-
 mlir/test/Conversion/SCFToEmitC/for.mlir         | 16 ++++++++--------
 mlir/test/Conversion/SCFToEmitC/if.mlir          |  4 ++--
 mlir/test/Dialect/EmitC/ops.mlir                 |  2 +-
 mlir/test/Target/Cpp/expressions.mlir            |  8 ++++----
 mlir/test/Target/Cpp/for.mlir                    | 16 ++++++++--------
 mlir/test/Target/Cpp/global.mlir                 |  4 ++--
 mlir/test/Target/Cpp/lvalue.mlir                 |  2 +-
 mlir/test/Target/Cpp/subscript.mlir              | 14 +++++++-------
 13 files changed, 42 insertions(+), 43 deletions(-)

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index edc533f6159cf..e1624776aa2dd 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -835,7 +835,7 @@ def EmitC_LogicalOrOp : EmitC_BinaryOp<"logical_or", [CExpression]> {
   let assemblyFormat = "operands attr-dict `:` type(operands)";
 }
 
-def EmitC_LValueLoadOp : EmitC_Op<"lvalue_load", [
+def EmitC_LoadOp : EmitC_Op<"load", [
   TypesMatchWith<"result type matches value type of 'operand'",
                   "operand", "result",
                   "::llvm::cast<LValueType>($_self).getValueType()">
diff --git a/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp b/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
index 2e8fbbad14d40..1392bf924002e 100644
--- a/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
+++ b/mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp
@@ -137,7 +137,7 @@ struct ConvertLoad final : public OpConversionPattern<memref::LoadOp> {
     auto subscript = rewriter.create<emitc::SubscriptOp>(
         op.getLoc(), arrayValue, operands.getIndices());
 
-    rewriter.replaceOpWithNewOp<emitc::LValueLoadOp>(op, resultTy, subscript);
+    rewriter.replaceOpWithNewOp<emitc::LoadOp>(op, resultTy, subscript);
     return success();
   }
 };
diff --git a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
index adcbf9009d041..d734e4c76ae67 100644
--- a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
+++ b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
@@ -85,7 +85,7 @@ SmallVector<Value> loadValues(const SmallVector<Value> &variables,
                               PatternRewriter &rewriter, Location loc) {
   return llvm::map_to_vector<>(variables, [&](Value var) {
     Type type = cast<emitc::LValueType>(var.getType()).getValueType();
-    return rewriter.create<emitc::LValueLoadOp>(loc, type, var).getResult();
+    return rewriter.create<emitc::LoadOp>(loc, type, var).getResult();
   });
 }
 
diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index 0982c21271444..449651a6f58e5 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -377,12 +377,11 @@ static LogicalResult printOperation(CppEmitter &emitter,
   return success();
 }
 
-static LogicalResult printOperation(CppEmitter &emitter,
-                                    emitc::LValueLoadOp lValueLoadOp) {
-  if (failed(emitter.emitAssignPrefix(*lValueLoadOp)))
+static LogicalResult printOperation(CppEmitter &emitter, emitc::LoadOp loadOp) {
+  if (failed(emitter.emitAssignPrefix(*loadOp)))
     return failure();
 
-  return emitter.emitOperand(lValueLoadOp.getOperand());
+  return emitter.emitOperand(loadOp.getOperand());
 }
 
 static LogicalResult printOperation(CppEmitter &emitter,
@@ -1508,8 +1507,8 @@ LogicalResult CppEmitter::emitOperation(Operation &op, bool trailingSemicolon) {
                 emitc::DivOp, emitc::ExpressionOp, emitc::ForOp, emitc::FuncOp,
                 emitc::GlobalOp, emitc::GetGlobalOp, emitc::IfOp,
                 emitc::IncludeOp, emitc::LogicalAndOp, emitc::LogicalNotOp,
-                emitc::LogicalOrOp, emitc::LValueLoadOp, emitc::MulOp,
-                emitc::RemOp, emitc::ReturnOp, emitc::SubOp, emitc::SubscriptOp,
+                emitc::LogicalOrOp, emitc::LoadOp, emitc::MulOp, emitc::RemOp,
+                emitc::ReturnOp, emitc::SubOp, emitc::SubscriptOp,
                 emitc::UnaryMinusOp, emitc::UnaryPlusOp, emitc::VariableOp,
                 emitc::VerbatimOp>(
               [&](auto op) { return printOperation(*this, op); })
diff --git a/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir b/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
index 15ffd815250d2..f4722da08cc40 100644
--- a/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
+++ b/mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir
@@ -21,7 +21,7 @@ func.func @memref_load(%i: index, %j: index) -> f32 {
   %0 = memref.alloca() : memref<4x8xf32>
 
   // CHECK-NEXT: %[[SUBSCRIPT:.*]] = emitc.subscript %[[ALLOCA]][%[[i]], %[[j]]] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<f32>
-  // CHECK-NEXT: %[[LOAD:.*]] = emitc.lvalue_load %[[SUBSCRIPT]] : <f32>
+  // CHECK-NEXT: %[[LOAD:.*]] = emitc.load %[[SUBSCRIPT]] : <f32>
   %1 = memref.load %0[%i, %j] : memref<4x8xf32>
   // CHECK-NEXT: return %[[LOAD]] : f32
   return %1 : f32
diff --git a/mlir/test/Conversion/SCFToEmitC/for.mlir b/mlir/test/Conversion/SCFToEmitC/for.mlir
index 32a9dfce7f4e6..83592187a9b68 100644
--- a/mlir/test/Conversion/SCFToEmitC/for.mlir
+++ b/mlir/test/Conversion/SCFToEmitC/for.mlir
@@ -52,14 +52,14 @@ func.func @for_yield(%arg0 : index, %arg1 : index, %arg2 : index) -> (f32, f32)
 // CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_5]] : <f32>
 // CHECK-NEXT:    emitc.assign %[[VAL_4]] : f32 to %[[VAL_6]] : <f32>
 // CHECK-NEXT:    emitc.for %[[VAL_7:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:      %[[VAL_8:.*]] = emitc.lvalue_load %[[VAL_5]] : <f32>
-// CHECK-NEXT:      %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_6]] : <f32>
+// CHECK-NEXT:      %[[VAL_8:.*]] = emitc.load %[[VAL_5]] : <f32>
+// CHECK-NEXT:      %[[VAL_9:.*]] = emitc.load %[[VAL_6]] : <f32>
 // CHECK-NEXT:      %[[VAL_10:.*]] = arith.addf %[[VAL_8]], %[[VAL_9]] : f32
 // CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_5]] : <f32>
 // CHECK-NEXT:      emitc.assign %[[VAL_10]] : f32 to %[[VAL_6]] : <f32>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    %[[VAL_11:.*]] = emitc.lvalue_load %[[VAL_5]] : <f32>
-// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.lvalue_load %[[VAL_6]] : <f32>
+// CHECK-NEXT:    %[[VAL_11:.*]] = emitc.load %[[VAL_5]] : <f32>
+// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.load %[[VAL_6]] : <f32>
 // CHECK-NEXT:    return %[[VAL_11]], %[[VAL_12]] : f32, f32
 // CHECK-NEXT:  }
 
@@ -80,17 +80,17 @@ func.func @nested_for_yield(%arg0 : index, %arg1 : index, %arg2 : index) -> f32
 // CHECK-NEXT:    %[[VAL_4:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
 // CHECK-NEXT:    emitc.assign %[[VAL_3]] : f32 to %[[VAL_4]] : <f32>
 // CHECK-NEXT:    emitc.for %[[VAL_5:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:      %[[VAL_6:.*]] = emitc.lvalue_load %[[VAL_4]] : <f32>
+// CHECK-NEXT:      %[[VAL_6:.*]] = emitc.load %[[VAL_4]] : <f32>
 // CHECK-NEXT:      %[[VAL_7:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
 // CHECK-NEXT:      emitc.assign %[[VAL_6]] : f32 to %[[VAL_7]] : <f32>
 // CHECK-NEXT:      emitc.for %[[VAL_8:.*]] = %[[VAL_0]] to %[[VAL_1]] step %[[VAL_2]] {
-// CHECK-NEXT:        %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_7]] : <f32>  
+// CHECK-NEXT:        %[[VAL_9:.*]] = emitc.load %[[VAL_7]] : <f32>  
 // CHECK-NEXT:        %[[VAL_10:.*]] = arith.addf %[[VAL_9]], %[[VAL_9]] : f32
 // CHECK-NEXT:        emitc.assign %[[VAL_10]] : f32 to %[[VAL_7]] : <f32>
 // CHECK-NEXT:      }
-// CHECK-NEXT:      %[[VAL_11:.*]] = emitc.lvalue_load %[[VAL_7]] : <f32>  
+// CHECK-NEXT:      %[[VAL_11:.*]] = emitc.load %[[VAL_7]] : <f32>  
 // CHECK-NEXT:      emitc.assign %[[VAL_11]] : f32 to %[[VAL_4]] : <f32>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.lvalue_load %[[VAL_4]] : <f32>  
+// CHECK-NEXT:    %[[VAL_12:.*]] = emitc.load %[[VAL_4]] : <f32>  
 // CHECK-NEXT:    return %[[VAL_12]] : f32
 // CHECK-NEXT:  }
diff --git a/mlir/test/Conversion/SCFToEmitC/if.mlir b/mlir/test/Conversion/SCFToEmitC/if.mlir
index 463cf1d3d9645..7d923785862d8 100644
--- a/mlir/test/Conversion/SCFToEmitC/if.mlir
+++ b/mlir/test/Conversion/SCFToEmitC/if.mlir
@@ -66,7 +66,7 @@ func.func @test_if_yield(%arg0: i1, %arg1: f32) -> (i32, f64) {
 // CHECK-NEXT:      emitc.assign %[[VAL_7]] : i32 to %[[VAL_3]] : <i32>
 // CHECK-NEXT:      emitc.assign %[[VAL_8]] : f64 to %[[VAL_4]] : <f64>
 // CHECK-NEXT:    }
-// CHECK-NEXT:    %[[VAL_9:.*]] = emitc.lvalue_load %[[VAL_3]] : <i32>
-// CHECK-NEXT:    %[[VAL_10:.*]] = emitc.lvalue_load %[[VAL_4]] : <f64>
+// CHECK-NEXT:    %[[VAL_9:.*]] = emitc.load %[[VAL_3]] : <i32>
+// CHECK-NEXT:    %[[VAL_10:.*]] = emitc.load %[[VAL_4]] : <f64>
 // CHECK-NEXT:    return %[[VAL_9]], %[[VAL_10]] : i32, f64
 // CHECK-NEXT:  }
diff --git a/mlir/test/Dialect/EmitC/ops.mlir b/mlir/test/Dialect/EmitC/ops.mlir
index 616a7ddbbf672..bccc94581368b 100644
--- a/mlir/test/Dialect/EmitC/ops.mlir
+++ b/mlir/test/Dialect/EmitC/ops.mlir
@@ -243,6 +243,6 @@ emitc.global const @myconstant : !emitc.array<2xi16> = dense<2>
 func.func @use_global(%i: index) -> f32 {
   %0 = emitc.get_global @myglobal : !emitc.array<2xf32>
   %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> !emitc.lvalue<f32>
-  %2 = emitc.lvalue_load %1 : <f32>
+  %2 = emitc.load %1 : <f32>
   return %2 : f32
 }
diff --git a/mlir/test/Target/Cpp/expressions.mlir b/mlir/test/Target/Cpp/expressions.mlir
index d9455e8e98177..6b67065f5d1a1 100644
--- a/mlir/test/Target/Cpp/expressions.mlir
+++ b/mlir/test/Target/Cpp/expressions.mlir
@@ -45,7 +45,7 @@ func.func @single_use(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32 {
     emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   }
-  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  %v_load = emitc.load %v : !emitc.lvalue<i32>
   return %v_load : i32
 }
 
@@ -234,7 +234,7 @@ func.func @multiple_uses(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32) -> i32
   }
   %q = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i1>
   emitc.assign %e : i1 to %q : !emitc.lvalue<i1>
-  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  %v_load = emitc.load %v : !emitc.lvalue<i32>
   return %v_load : i32
 }
 
@@ -291,7 +291,7 @@ func.func @different_expressions(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32)
     emitc.assign %arg0 : i32 to %v : !emitc.lvalue<i32>
     emitc.yield
   }
-  %v_load = emitc.lvalue_load %v : !emitc.lvalue<i32>
+  %v_load = emitc.load %v : !emitc.lvalue<i32>
   return %v_load : i32
 }
 
@@ -339,6 +339,6 @@ func.func @expression_with_subscript_user(%arg0: !emitc.ptr<!emitc.opaque<"void"
     emitc.yield %0 : !emitc.ptr<i32>
   }
   %res = emitc.subscript %0[%c0] : (!emitc.ptr<i32>, i64) -> !emitc.lvalue<i32>
-  %res_load = emitc.lvalue_load %res : !emitc.lvalue<i32>
+  %res_load = emitc.load %res : !emitc.lvalue<i32>
   return %res_load : i32
 }
diff --git a/mlir/test/Target/Cpp/for.mlir b/mlir/test/Target/Cpp/for.mlir
index 14d3f05d6a08e..6a446eaf4add3 100644
--- a/mlir/test/Target/Cpp/for.mlir
+++ b/mlir/test/Target/Cpp/for.mlir
@@ -47,17 +47,17 @@ func.func @test_for_yield() {
   emitc.assign %s0 : i32 to %2 : !emitc.lvalue<i32>
   emitc.assign %p0 : f32 to %3 : !emitc.lvalue<f32>
   emitc.for %iter = %start to %stop step %step {
-    %4 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+    %4 = emitc.load %2 : !emitc.lvalue<i32>
     %sn = emitc.call_opaque "add"(%4, %iter) : (i32, index) -> i32
-    %5 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+    %5 = emitc.load %3 : !emitc.lvalue<f32>
     %pn = emitc.call_opaque "mul"(%5, %iter) : (f32, index) -> f32
     emitc.assign %sn : i32 to %2 : !emitc.lvalue<i32>
     emitc.assign %pn : f32 to %3 : !emitc.lvalue<f32>
     emitc.yield
   }
-  %6 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+  %6 = emitc.load %2 : !emitc.lvalue<i32>
   emitc.assign %6 : i32 to %0 : !emitc.lvalue<i32>
-  %7 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+  %7 = emitc.load %3 : !emitc.lvalue<f32>
   emitc.assign %7 : f32 to %1 : !emitc.lvalue<f32>
 
   return
@@ -144,17 +144,17 @@ func.func @test_for_yield_2() {
   emitc.assign %s0 : i32 to %2 : !emitc.lvalue<i32>
   emitc.assign %p0 : f32 to %3 : !emitc.lvalue<f32>
   emitc.for %iter = %start to %stop step %step {
-    %4 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+    %4 = emitc.load %2 : !emitc.lvalue<i32>
     %sn = emitc.call_opaque "add"(%4, %iter) : (i32, index) -> i32
-    %5 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+    %5 = emitc.load %3 : !emitc.lvalue<f32>
     %pn = emitc.call_opaque "mul"(%5, %iter) : (f32, index) -> f32
     emitc.assign %sn : i32 to %2 : !emitc.lvalue<i32>
     emitc.assign %pn : f32 to %3 : !emitc.lvalue<f32>
     emitc.yield
   }
-  %6 = emitc.lvalue_load %2 : !emitc.lvalue<i32>
+  %6 = emitc.load %2 : !emitc.lvalue<i32>
   emitc.assign %6 : i32 to %0 : !emitc.lvalue<i32>
-  %7 = emitc.lvalue_load %3 : !emitc.lvalue<f32>
+  %7 = emitc.load %3 : !emitc.lvalue<f32>
   emitc.assign %7 : f32 to %1 : !emitc.lvalue<f32>
 
   return
diff --git a/mlir/test/Target/Cpp/global.mlir b/mlir/test/Target/Cpp/global.mlir
index 32eb8c6cf6f87..bd3ab126692e4 100644
--- a/mlir/test/Target/Cpp/global.mlir
+++ b/mlir/test/Target/Cpp/global.mlir
@@ -39,7 +39,7 @@ emitc.global @opaque_init : !emitc.opaque<"char"> = #emitc.opaque<"CHAR_MIN">
 
 func.func @use_global_scalar_read() -> i32 {
   %0 = emitc.get_global @myglobal_int : !emitc.lvalue<i32>
-  %1 = emitc.lvalue_load %0 : !emitc.lvalue<i32>
+  %1 = emitc.load %0 : !emitc.lvalue<i32>
   return %1 : i32
 }
 // CPP-DEFAULT-LABEL: int32_t use_global_scalar_read()
@@ -69,7 +69,7 @@ func.func @use_global_scalar_write(%arg0 : i32) {
 func.func @use_global_array_read(%i: index) -> f32 {
   %0 = emitc.get_global @myglobal : !emitc.array<2xf32>
   %1 = emitc.subscript %0[%i] : (!emitc.array<2xf32>, index) -> !emitc.lvalue<f32>
-  %2 = emitc.lvalue_load %1 : <f32>
+  %2 = emitc.load %1 : <f32>
   return %2 : f32
 }
 // CPP-DEFAULT-LABEL: float use_global_array_read
diff --git a/mlir/test/Target/Cpp/lvalue.mlir b/mlir/test/Target/Cpp/lvalue.mlir
index 5ef7fb2763246..2aa438eb6371c 100644
--- a/mlir/test/Target/Cpp/lvalue.mlir
+++ b/mlir/test/Target/Cpp/lvalue.mlir
@@ -6,7 +6,7 @@ emitc.func @lvalue_variables(%v1: i32, %v2: i32) -> i32 {
   emitc.assign %val : i32 to %variable : !emitc.lvalue<i32>
   %addr = emitc.apply "&"(%variable) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   emitc.call @zero (%addr) : (!emitc.ptr<i32>) -> ()
-  %updated_val = emitc.lvalue_load %variable : !emitc.lvalue<i32>
+  %updated_val = emitc.load %variable : !emitc.lvalue<i32>
   %neg_one = "emitc.constant"() {value = -1 : i32} : () -> i32
   emitc.assign %neg_one : i32 to %variable : !emitc.lvalue<i32>
   emitc.return %updated_val : i32
diff --git a/mlir/test/Target/Cpp/subscript.mlir b/mlir/test/Target/Cpp/subscript.mlir
index b5c94c146712e..7f015c210796e 100644
--- a/mlir/test/Target/Cpp/subscript.mlir
+++ b/mlir/test/Target/Cpp/subscript.mlir
@@ -4,7 +4,7 @@
 func.func @load_store_array(%arg0: !emitc.array<4x8xf32>, %arg1: !emitc.array<3x5xf32>, %arg2: index, %arg3: index) {
   %0 = emitc.subscript %arg0[%arg2, %arg3] : (!emitc.array<4x8xf32>, index, index) -> !emitc.lvalue<f32>
   %1 = emitc.subscript %arg1[%arg2, %arg3] : (!emitc.array<3x5xf32>, index, index) -> !emitc.lvalue<f32>
-  %2 = emitc.lvalue_load %0 : <f32>
+  %2 = emitc.load %0 : <f32>
   emitc.assign %2 : f32 to %1 : !emitc.lvalue<f32>
   return
 }
@@ -22,7 +22,7 @@ func.func @load_store_array(%arg0: !emitc.array<4x8xf32>, %arg1: !emitc.array<3x
 func.func @load_store_pointer(%arg0: !emitc.ptr<f32>, %arg1: !emitc.ptr<f32>, %arg2: index, %arg3: index) {
   %0 = emitc.subscript %arg0[%arg2] : (!emitc.ptr<f32>, index) -> !emitc.lvalue<f32>
   %1 = emitc.subscript %arg1[%arg3] : (!emitc.ptr<f32>, index) -> !emitc.lvalue<f32>
-  %2 = emitc.lvalue_load %0 : <f32>
+  %2 = emitc.load %0 : <f32>
   emitc.assign %2 : f32 to %1 : <f32>
   return
 }
@@ -40,7 +40,7 @@ func.func @load_store_pointer(%arg0: !emitc.ptr<f32>, %arg1: !emitc.ptr<f32>, %a
 func.func @load_store_opaque(%arg0: !emitc.opaque<"std::map<char, int>">, %arg1: !emitc.opaque<"std::map<char, int>">, %arg2: !emitc.opaque<"char">, %arg3: !emitc.opaque<"char">) {
   %0 = emitc.subscript %arg0[%arg2] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.lvalue<!emitc.opaque<"int">>
   %1 = emitc.subscript %arg1[%arg3] : (!emitc.opaque<"std::map<char, int>">, !emitc.opaque<"char">) -> !emitc.lvalue<!emitc.opaque<"int">>
-  %2 = emitc.lvalue_load %0 : <!emitc.opaque<"int">>
+  %2 = emitc.load %0 : <!emitc.opaque<"int">>
   emitc.assign %2 : !emitc.opaque<"int"> to %1 : <!emitc.opaque<"int">>
   return
 }
@@ -64,12 +64,12 @@ emitc.func @call_arg(%arg0: !emitc.array<4x8xf32>, %i: i32, %j: i16,
   %0 = emitc.subscript %arg0[%i, %j] : (!emitc.array<4x8xf32>, i32, i16) -> !emitc.lvalue<f32>
   %1 = emitc.subscript %arg0[%j, %k] : (!emitc.array<4x8xf32>, i16, i8) -> !emitc.lvalue<f32>
 
-  %2 = emitc.lvalue_load %0 : <f32>
+  %2 = emitc.load %0 : <f32>
   emitc.call @func1 (%2) : (f32) -> ()
-  %3 = emitc.lvalue_load %1 : <f32>
+  %3 = emitc.load %1 : <f32>
   emitc.call_opaque "func2" (%3) : (f32) -> ()
-  %4 = emitc.lvalue_load %0 : <f32>
-  %5 = emitc.lvalue_load %1 : <f32>
+  %4 = emitc.load %0 : <f32>
+  %5 = emitc.load %1 : <f32>
   emitc.call_opaque "func3" (%4, %5) { args = [1 : index, 0 : index] } : (f32, f32) -> ()
   emitc.return
 }

>From 07a027818e06b32823f4c72c4fed90dc5a5dabb1 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Thu, 13 Jun 2024 08:03:40 +0000
Subject: [PATCH 09/13] Restore xpression_with_dereference test

---
 mlir/test/Dialect/EmitC/transforms.mlir | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/mlir/test/Dialect/EmitC/transforms.mlir b/mlir/test/Dialect/EmitC/transforms.mlir
index 996fd327f7af7..bd0dd820609bf 100644
--- a/mlir/test/Dialect/EmitC/transforms.mlir
+++ b/mlir/test/Dialect/EmitC/transforms.mlir
@@ -64,6 +64,26 @@ func.func @expression_with_call(%arg0: i32, %arg1: i32, %arg2: i32, %arg3: i32)
   return %c : i1
 }
 
+// CHECK-LABEL: func.func @expression_with_dereference(
+// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>) -> i1 {
+// CHECK:         %[[VAL_3:.*]] = emitc.expression : i32 {
+// CHECK:           %[[VAL_4:.*]] = emitc.apply "*"(%[[VAL_2]]) : (!emitc.ptr<i32>) -> i32
+// CHECK:           emitc.yield %[[VAL_4]] : i32
+// CHECK:         }
+// CHECK:         %[[VAL_5:.*]] = emitc.expression : i1 {
+// CHECK:           %[[VAL_6:.*]] = emitc.mul %[[VAL_0]], %[[VAL_1]] : (i32, i32) -> i32
+// CHECK:           %[[VAL_7:.*]] = emitc.cmp lt, %[[VAL_6]], %[[VAL_3]] : (i32, i32) -> i1
+// CHECK:         return %[[VAL_5]] : i1
+// CHECK:       }
+
+func.func @expression_with_dereference(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>) -> i1 {
+  %a = emitc.mul %arg0, %arg1 : (i32, i32) -> i32
+  %b = emitc.apply "*"(%arg2) : (!emitc.ptr<i32>) -> (i32)
+  %c = emitc.cmp lt, %a, %b :(i32, i32) -> i1
+  return %c : i1
+}
+
+
 // CHECK-LABEL: func.func @expression_with_address_taken(
 // CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>, %[[VAL_3:.*]]: !emitc.lvalue<i32>) -> i1 {
 // CHECK:         %[[VAL_4:.*]] = emitc.expression : i1 {

>From 2233e7f35459a4f43c530fe1e3292668eea7f793 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Thu, 13 Jun 2024 08:19:27 +0000
Subject: [PATCH 10/13] Drop unnecessary check

---
 mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp b/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
index 758b8527c2fa5..82bd031430d36 100644
--- a/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
+++ b/mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp
@@ -38,8 +38,7 @@ struct FormExpressionsPass
     auto matchFun = [&](Operation *op) {
       if (op->hasTrait<OpTrait::emitc::CExpression>() &&
           !op->getParentOfType<emitc::ExpressionOp>() &&
-          op->getNumResults() == 1 &&
-          isSupportedEmitCType(op->getResult(0).getType()))
+          op->getNumResults() == 1)
         createExpression(op, builder);
     };
     rootOp->walk(matchFun);

>From 4791fd660dbd9ddd00190b670907bf42349ad4bc Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Thu, 13 Jun 2024 15:20:52 +0000
Subject: [PATCH 11/13] Remove result name

---
 mlir/include/mlir/Dialect/EmitC/IR/EmitC.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
index e1624776aa2dd..3cea6c8539296 100644
--- a/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
+++ b/mlir/include/mlir/Dialect/EmitC/IR/EmitC.td
@@ -1029,7 +1029,7 @@ def EmitC_VariableOp : EmitC_Op<"variable", []> {
 
   let arguments = (ins EmitC_OpaqueOrTypedAttr:$value);
   let results = (outs Res<AnyTypeOf<[EmitC_ArrayType, EmitC_LValueType]>, "",
-                          [MemAlloc<DefaultResource, 0, FullEffect>]>:$memref);
+                          [MemAlloc<DefaultResource, 0, FullEffect>]>);
 
   let hasVerifier = 1;
 }

>From b795bb31462579f53e543e31beb44d331ffc2425 Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Thu, 13 Jun 2024 15:25:03 +0000
Subject: [PATCH 12/13] Review comment

---
 mlir/lib/Dialect/EmitC/IR/EmitC.cpp | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
index ebedfa3696041..539686389e283 100644
--- a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
+++ b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
@@ -61,9 +61,6 @@ void mlir::emitc::buildTerminatedBody(OpBuilder &builder, Location loc) {
 bool mlir::emitc::isSupportedEmitCType(Type type) {
   if (llvm::isa<emitc::OpaqueType>(type))
     return true;
-  if (auto lType = llvm::dyn_cast<emitc::LValueType>(type))
-    // lvalue types are only allowed in a few places.
-    return false;
   if (auto ptrType = llvm::dyn_cast<emitc::PointerType>(type))
     return isSupportedEmitCType(ptrType.getPointee());
   if (auto arrayType = llvm::dyn_cast<emitc::ArrayType>(type)) {

>From 64e776c22abd3e40d3163b9c7787a63fd315446a Mon Sep 17 00:00:00 2001
From: Simon Camphausen <simon.camphausen at iml.fraunhofer.de>
Date: Thu, 13 Jun 2024 16:09:11 +0000
Subject: [PATCH 13/13] Disallow lvalue as argument types

---
 mlir/lib/Dialect/EmitC/IR/EmitC.cpp      |  4 ++++
 mlir/lib/Target/Cpp/TranslateToCpp.cpp   |  5 +++++
 mlir/test/Dialect/EmitC/invalid_ops.mlir | 26 +++++++++++++++++-------
 mlir/test/Dialect/EmitC/ops.mlir         |  8 +++++---
 mlir/test/Dialect/EmitC/transforms.mlir  |  8 +++++---
 mlir/test/Target/Cpp/common-cpp.mlir     | 15 +++++++-------
 mlir/test/Target/Cpp/invalid.mlir        |  7 +++++++
 7 files changed, 53 insertions(+), 20 deletions(-)

diff --git a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
index 539686389e283..1d7b926b3b1a6 100644
--- a/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
+++ b/mlir/lib/Dialect/EmitC/IR/EmitC.cpp
@@ -539,6 +539,10 @@ void FuncOp::print(OpAsmPrinter &p) {
 }
 
 LogicalResult FuncOp::verify() {
+  if (llvm::any_of(getArgumentTypes(), llvm::IsaPred<LValueType>)) {
+    return emitOpError("cannot have lvalue type as argument");
+  }
+
   if (getNumResults() > 1)
     return emitOpError("requires zero or exactly one result, but has ")
            << getNumResults();
diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index 449651a6f58e5..f83d17ba56b3c 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -1030,6 +1030,11 @@ static LogicalResult printOperation(CppEmitter &emitter,
         "with multiple blocks needs variables declared at top");
   }
 
+  if (llvm::any_of(functionOp.getArgumentTypes(), llvm::IsaPred<LValueType>)) {
+    return functionOp.emitOpError()
+           << "cannot emit lvalue type as argument type";
+  }
+
   if (llvm::any_of(functionOp.getResultTypes(), llvm::IsaPred<ArrayType>)) {
     return functionOp.emitOpError() << "cannot emit array type as result type";
   }
diff --git a/mlir/test/Dialect/EmitC/invalid_ops.mlir b/mlir/test/Dialect/EmitC/invalid_ops.mlir
index 261e67607fc4f..61fb53c531ac5 100644
--- a/mlir/test/Dialect/EmitC/invalid_ops.mlir
+++ b/mlir/test/Dialect/EmitC/invalid_ops.mlir
@@ -88,17 +88,19 @@ func.func @array_result() {
 
 // -----
 
-func.func @empty_operator(%arg : !emitc.lvalue<i32>) {
+func.func @empty_operator() {
+    %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
     // expected-error @+1 {{'emitc.apply' op applicable operator must not be empty}}
-    %2 = emitc.apply ""(%arg) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+    %1 = emitc.apply ""(%0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
     return
 }
 
 // -----
 
-func.func @illegal_operator(%arg : !emitc.lvalue<i32>) {
+func.func @illegal_operator() {
+    %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
     // expected-error @+1 {{'emitc.apply' op applicable operator is illegal}}
-    %2 = emitc.apply "+"(%arg) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+    %1 = emitc.apply "+"(%0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
     return
 }
 
@@ -225,10 +227,13 @@ func.func @test_misplaced_yield() {
 
 // -----
 
-func.func @test_assign_to_non_variable(%arg1: f32, %arg2: !emitc.lvalue<f32>) {
+func.func @test_assign_to_block_argument(%arg0: f32) {
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<f32>
+  cf.br ^bb1(%0 : !emitc.lvalue<f32>)
+^bb1(%a : !emitc.lvalue<f32>):
   // expected-error @+1 {{'emitc.assign' op cannot assign to block argument}}
-  emitc.assign %arg1 : f32 to %arg2 : !emitc.lvalue<f32>
-  return
+  emitc.assign %arg0 : f32 to %a : !emitc.lvalue<f32>
+  func.return
 }
 
 // -----
@@ -329,6 +334,13 @@ emitc.func @return_type_mismatch() -> i32 {
 
 // -----
 
+// expected-error at +1 {{'emitc.func' op cannot have lvalue type as argument}}
+emitc.func @argument_type_lvalue(%arg : !emitc.lvalue<i32>) {
+  emitc.return
+}
+
+// -----
+
 // expected-error at +1 {{'emitc.func' op cannot return array type}}
 emitc.func @return_type_array(%arg : !emitc.array<4xi32>) -> !emitc.array<4xi32> {
   emitc.return %arg : !emitc.array<4xi32>
diff --git a/mlir/test/Dialect/EmitC/ops.mlir b/mlir/test/Dialect/EmitC/ops.mlir
index bccc94581368b..a8178cbce2378 100644
--- a/mlir/test/Dialect/EmitC/ops.mlir
+++ b/mlir/test/Dialect/EmitC/ops.mlir
@@ -44,9 +44,11 @@ func.func @c() {
   return
 }
 
-func.func @a(%arg0: !emitc.lvalue<i32>, %arg1: !emitc.lvalue<i32>) {
-  %1 = "emitc.apply"(%arg0) {applicableOperator = "&"} : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
-  %2 = emitc.apply "&"(%arg1) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+func.func @a() {
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %1 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %2 = "emitc.apply"(%0) {applicableOperator = "&"} : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  %3 = emitc.apply "&"(%1) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   return
 }
 
diff --git a/mlir/test/Dialect/EmitC/transforms.mlir b/mlir/test/Dialect/EmitC/transforms.mlir
index bd0dd820609bf..6cfac6462623c 100644
--- a/mlir/test/Dialect/EmitC/transforms.mlir
+++ b/mlir/test/Dialect/EmitC/transforms.mlir
@@ -85,7 +85,8 @@ func.func @expression_with_dereference(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr
 
 
 // CHECK-LABEL: func.func @expression_with_address_taken(
-// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>, %[[VAL_3:.*]]: !emitc.lvalue<i32>) -> i1 {
+// CHECK-SAME:      %[[VAL_0:.*]]: i32, %[[VAL_1:.*]]: i32, %[[VAL_2:.*]]: !emitc.ptr<i32>) -> i1 {
+// CHECK:         %[[VAL_3:.*]] = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
 // CHECK:         %[[VAL_4:.*]] = emitc.expression : i1 {
 // CHECK:           %[[VAL_5:.*]] = emitc.apply "&"(%[[VAL_3]]) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
 // CHECK:           %[[VAL_6:.*]] = emitc.add %[[VAL_5]], %[[VAL_1]] : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
@@ -95,8 +96,9 @@ func.func @expression_with_dereference(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr
 // CHECK:         return %[[VAL_4]] : i1
 // CHECK:       }
 
-func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>, %arg3: !emitc.lvalue<i32>) -> i1 {
-  %a = emitc.apply "&"(%arg3) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+func.func @expression_with_address_taken(%arg0: i32, %arg1: i32, %arg2: !emitc.ptr<i32>) -> i1 {
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
+  %a = emitc.apply "&"(%0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   %b = emitc.add %a, %arg1 : (!emitc.ptr<i32>, i32) -> !emitc.ptr<i32>
   %c = emitc.cmp lt, %b, %arg2 :(!emitc.ptr<i32>, !emitc.ptr<i32>) -> i1
   return %c : i1
diff --git a/mlir/test/Target/Cpp/common-cpp.mlir b/mlir/test/Target/Cpp/common-cpp.mlir
index 8af29531905ba..2036a10e0cad1 100644
--- a/mlir/test/Target/Cpp/common-cpp.mlir
+++ b/mlir/test/Target/Cpp/common-cpp.mlir
@@ -82,19 +82,20 @@ func.func @opaque_types(%arg0: !emitc.opaque<"bool">, %arg1: !emitc.opaque<"char
   return %2 : !emitc.opaque<"status_t">
 }
 
-// CHECK-LABEL: int32_t* apply(
-// CHECK-SAME: int32_t [[V1:[^ ]*]]) {
-func.func @apply(%arg0: !emitc.lvalue<i32>) -> !emitc.ptr<i32> {
+// CHECK-LABEL: int32_t* apply() {
+func.func @apply() -> !emitc.ptr<i32> {
+  // CHECK-NEXT: int32_t [[V1:[^ ]*]];
+  %0 = "emitc.variable"() <{value = #emitc.opaque<"">}> : () -> !emitc.lvalue<i32>
   // CHECK-NEXT: int32_t* [[V2:[^ ]*]] = &[[V1]];
-  %0 = emitc.apply "&"(%arg0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
+  %1 = emitc.apply "&"(%0) : (!emitc.lvalue<i32>) -> !emitc.ptr<i32>
   // CHECK-NEXT: int32_t [[V3:[^ ]*]];
   %2 = "emitc.variable"() {value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
   // CHECK-NEXT: int32_t [[V4:[^ ]*]] = *[[V2]];
-  %1 = emitc.apply "*"(%0) : (!emitc.ptr<i32>) -> i32
+  %3 = emitc.apply "*"(%1) : (!emitc.ptr<i32>) -> i32
   // CHECK-NEXT: [[V3]] = [[V4]];
-  emitc.assign %1 : i32 to %2 : !emitc.lvalue<i32>
+  emitc.assign %3 : i32 to %2 : !emitc.lvalue<i32>
   // CHECK-NEXT: return [[V2]];
-  return %0 : !emitc.ptr<i32>
+  return %1 : !emitc.ptr<i32>
 }
 
 // CHECK: void array_type(int32_t v1[3], float v2[10][20])
diff --git a/mlir/test/Target/Cpp/invalid.mlir b/mlir/test/Target/Cpp/invalid.mlir
index 14fd0cd56170b..fc35039e3e55f 100644
--- a/mlir/test/Target/Cpp/invalid.mlir
+++ b/mlir/test/Target/Cpp/invalid.mlir
@@ -74,6 +74,13 @@ func.func @pointer_to_array(%arg0 : !emitc.ptr<!emitc.array<4xf32>>) {
 
 // -----
 
+// expected-error at +1 {{cannot emit lvalue type as argument type}}
+func.func @lvalue_as_argument(%arg: !emitc.lvalue<i8>) {
+   return
+}
+
+// -----
+
 // expected-error at +1 {{cannot emit array type as result type}}
 func.func @array_as_result(%arg: !emitc.array<4xi8>) -> (!emitc.array<4xi8>) {
    return %arg : !emitc.array<4xi8>



More information about the Mlir-commits mailing list