[Mlir-commits] [mlir] [mlir][emitc] Lower SCF using memrefs (PR #93371)

[Matthias Gehre]

================
@@ -63,21 +65,41 @@ static SmallVector<Value> createVariablesForResults(T op,
 
   for (OpResult result : op.getResults()) {
     Type resultType = result.getType();
-    emitc::OpaqueAttr noInit = emitc::OpaqueAttr::get(context, "");
-    emitc::VariableOp var =
-        rewriter.create<emitc::VariableOp>(loc, resultType, noInit);
+    SmallVector<OpFoldResult> dimensions = {rewriter.getIndexAttr(1)};
+    memref::AllocaOp var =
+        rewriter.create<memref::AllocaOp>(loc, dimensions, resultType);
     resultVariables.push_back(var);
   }
 
   return resultVariables;
 }
 
-// Create a series of assign ops assigning given values to given variables at
+// Create a series of load ops reading the values of given variables at
+// the current insertion point of given rewriter.
+static SmallVector<Value> readValues(SmallVector<Value> &variables,
+                                     PatternRewriter &rewriter, Location loc) {
+  Value zero;
+  if (variables.size() > 0)
+    zero = rewriter.create<arith::ConstantOp>(loc, rewriter.getIndexAttr(0));
+  SmallVector<Value> values;
+  SmallVector<Value> indices = {zero};
+  for (Value var : variables)
+    values.push_back(
+        rewriter.create<memref::LoadOp>(loc, var, indices).getResult());
+  return values;
+}
+
+// Create a series of store ops assigning given values to given variables at
 // the current insertion point of given rewriter.
 static void assignValues(ValueRange values, SmallVector<Value> &variables,
                          PatternRewriter &rewriter, Location loc) {
-  for (auto [value, var] : llvm::zip(values, variables))
-    rewriter.create<emitc::AssignOp>(loc, var, value);
+  Value zero;
+  if (variables.size() > 0)
----------------
mgehre-amd wrote:

nit: would this work? same in readValues()
```suggestion
  if (variables.empty())
    return;
```

https://github.com/llvm/llvm-project/pull/93371