[clang] [CIR] Upstream support for promoted types with unary plus/minus (PR #133829)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Andy Kaylor (andykaylor)

<details>
<summary>Changes</summary>

The initial upstreaming of unary operations left promoted types unhandled for the unary plus and minus operators. This change implements support for promoted types and performs a bit of related code cleanup.

---
Full diff: https://github.com/llvm/llvm-project/pull/133829.diff


3 Files Affected:

- (modified) clang/lib/CIR/CodeGen/CIRGenBuilder.h (+9) 
- (modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+17-21) 
- (modified) clang/test/CIR/CodeGen/unary.cpp (+42) 


``````````diff
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuilder.h b/clang/lib/CIR/CodeGen/CIRGenBuilder.h
index 03fb227a464a1..61a747254b3d0 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuilder.h
+++ b/clang/lib/CIR/CodeGen/CIRGenBuilder.h
@@ -160,6 +160,15 @@ class CIRGenBuilderTy : public cir::CIRBaseBuilderTy {
     llvm_unreachable("negation for the given type is NYI");
   }
 
+  // TODO: split this to createFPExt/createFPTrunc when we have dedicated cast
+  // operations.
+  mlir::Value createFloatingCast(mlir::Value v, mlir::Type destType) {
+    assert(!cir::MissingFeatures::fpConstraints());
+
+    return create<cir::CastOp>(v.getLoc(), destType, cir::CastKind::floating,
+                               v);
+  }
+
   mlir::Value createFSub(mlir::Location loc, mlir::Value lhs, mlir::Value rhs) {
     assert(!cir::MissingFeatures::metaDataNode());
     assert(!cir::MissingFeatures::fpConstraints());
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 2cf92dfbf3a5b..44377aca7b82e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -88,13 +88,11 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
   //===--------------------------------------------------------------------===//
 
   mlir::Value emitPromotedValue(mlir::Value result, QualType promotionType) {
-    cgf.cgm.errorNYI(result.getLoc(), "floating cast for promoted value");
-    return {};
+    return builder.createFloatingCast(result, cgf.convertType(promotionType));
   }
 
   mlir::Value emitUnPromotedValue(mlir::Value result, QualType exprType) {
-    cgf.cgm.errorNYI(result.getLoc(), "floating cast for unpromoted value");
-    return {};
+    return builder.createFloatingCast(result, cgf.convertType(exprType));
   }
 
   mlir::Value emitPromoted(const Expr *e, QualType promotionType);
@@ -448,36 +446,34 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
     llvm_unreachable("Unexpected signed overflow behavior kind");
   }
 
-  mlir::Value VisitUnaryPlus(const UnaryOperator *e,
-                             QualType promotionType = QualType()) {
-    if (!promotionType.isNull())
-      cgf.cgm.errorNYI(e->getSourceRange(), "VisitUnaryPlus: promotionType");
-    assert(!cir::MissingFeatures::opUnaryPromotionType());
-    mlir::Value result = emitUnaryPlusOrMinus(e, cir::UnaryOpKind::Plus);
-    return result;
+  mlir::Value VisitUnaryPlus(const UnaryOperator *e) {
+    return emitUnaryPlusOrMinus(e, cir::UnaryOpKind::Plus);
   }
 
-  mlir::Value VisitUnaryMinus(const UnaryOperator *e,
-                              QualType promotionType = QualType()) {
-    if (!promotionType.isNull())
-      cgf.cgm.errorNYI(e->getSourceRange(), "VisitUnaryMinus: promotionType");
-    assert(!cir::MissingFeatures::opUnaryPromotionType());
-    mlir::Value result = emitUnaryPlusOrMinus(e, cir::UnaryOpKind::Minus);
-    return result;
+  mlir::Value VisitUnaryMinus(const UnaryOperator *e) {
+    return emitUnaryPlusOrMinus(e, cir::UnaryOpKind::Minus);
   }
 
   mlir::Value emitUnaryPlusOrMinus(const UnaryOperator *e,
                                    cir::UnaryOpKind kind) {
     ignoreResultAssign = false;
 
-    assert(!cir::MissingFeatures::opUnaryPromotionType());
-    mlir::Value operand = Visit(e->getSubExpr());
+    QualType promotionType = getPromotionType(e->getSubExpr()->getType());
+
+    mlir::Value operand;
+    if (!promotionType.isNull())
+      operand = cgf.emitPromotedScalarExpr(e->getSubExpr(), promotionType);
+    else
+      operand = Visit(e->getSubExpr());
 
     assert(!cir::MissingFeatures::opUnarySignedOverflow());
 
     // NOTE: LLVM codegen will lower this directly to either a FNeg
     // or a Sub instruction.  In CIR this will be handled later in LowerToLLVM.
-    return emitUnaryOp(e, kind, operand);
+    mlir::Value result = emitUnaryOp(e, kind, operand);
+    if (result && !promotionType.isNull())
+      return emitUnPromotedValue(result, e->getType());
+    return result;
   }
 
   mlir::Value emitUnaryOp(const UnaryOperator *e, cir::UnaryOpKind kind,
diff --git a/clang/test/CIR/CodeGen/unary.cpp b/clang/test/CIR/CodeGen/unary.cpp
index 3e041e14ce177..5cb0e9b1ea5bd 100644
--- a/clang/test/CIR/CodeGen/unary.cpp
+++ b/clang/test/CIR/CodeGen/unary.cpp
@@ -405,3 +405,45 @@ float fpPostInc2() {
 // OGCG:   store float %[[A_INC]], ptr %[[A]], align 4
 // OGCG:   store float %[[A_LOAD]], ptr %[[B]], align 4
 // OGCG:   %[[B_TO_OUTPUT:.*]] = load float, ptr %[[B]], align 4
+
+_Float16 fp16UPlus(_Float16 f) {
+  return +f;
+}
+
+// CHECK: cir.func @fp16UPlus({{.*}}) -> !cir.f16
+// CHECK:   %[[INPUT:.*]] = cir.load %[[F:.*]]
+// CHECK:   %[[PROMOTED:.*]] = cir.cast(floating, %[[INPUT]] : !cir.f16), !cir.float
+// CHECK:   %[[RESULT:.*]] = cir.unary(plus, %[[PROMOTED]])
+// CHECK:   %[[UNPROMOTED:.*]] = cir.cast(floating, %[[RESULT]] : !cir.float), !cir.f16
+
+// LLVM: define half @fp16UPlus({{.*}})
+// LLVM:   %[[F_LOAD:.*]] = load half, ptr %{{.*}}, align 2
+// LLVM:   %[[PROMOTED:.*]] = fpext half %[[F_LOAD]] to float
+// LLVM:   %[[UNPROMOTED:.*]] = fptrunc float %[[PROMOTED]] to half
+
+// OGCG: define{{.*}} half @_Z9fp16UPlusDF16_({{.*}})
+// OGCG:   %[[F_LOAD:.*]] = load half, ptr %{{.*}}, align 2
+// OGCG:   %[[PROMOTED:.*]] = fpext half %[[F_LOAD]] to float
+// OGCG:   %[[UNPROMOTED:.*]] = fptrunc float %[[PROMOTED]] to half
+
+_Float16 fp16UMinus(_Float16 f) {
+  return -f;
+}
+
+// CHECK: cir.func @fp16UMinus({{.*}}) -> !cir.f16
+// CHECK:   %[[INPUT:.*]] = cir.load %[[F:.*]]
+// CHECK:   %[[PROMOTED:.*]] = cir.cast(floating, %[[INPUT]] : !cir.f16), !cir.float
+// CHECK:   %[[RESULT:.*]] = cir.unary(minus, %[[PROMOTED]])
+// CHECK:   %[[UNPROMOTED:.*]] = cir.cast(floating, %[[RESULT]] : !cir.float), !cir.f16
+
+// LLVM: define half @fp16UMinus({{.*}})
+// LLVM:   %[[F_LOAD:.*]] = load half, ptr %{{.*}}, align 2
+// LLVM:   %[[PROMOTED:.*]] = fpext half %[[F_LOAD]] to float
+// LLVM:   %[[RESULT:.*]] = fneg float %[[PROMOTED]]
+// LLVM:   %[[UNPROMOTED:.*]] = fptrunc float %[[RESULT]] to half
+
+// OGCG: define{{.*}} half @_Z10fp16UMinusDF16_({{.*}})
+// OGCG:   %[[F_LOAD:.*]] = load half, ptr %{{.*}}, align 2
+// OGCG:   %[[PROMOTED:.*]] = fpext half %[[F_LOAD]] to float
+// OGCG:   %[[RESULT:.*]] = fneg float %[[PROMOTED]]
+// OGCG:   %[[UNPROMOTED:.*]] = fptrunc float %[[RESULT]] to half

``````````

</details>


https://github.com/llvm/llvm-project/pull/133829