[llvm-branch-commits] [flang] [flang] support fir.alloca operations inside of omp reduction ops (PR #84952)

[Tom Eccles via llvm-branch-commits]

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@@ -410,8 +410,15 @@ class FIROpConversion : public mlir::ConvertOpToLLVMPattern<FromOp> {
       mlir::ConversionPatternRewriter &rewriter) const {
     auto thisPt = rewriter.saveInsertionPoint();
     mlir::Operation *parentOp = rewriter.getInsertionBlock()->getParentOp();
-    mlir::Block *insertBlock = getBlockForAllocaInsert(parentOp);
-    rewriter.setInsertionPointToStart(insertBlock);
+    if (mlir::isa<mlir::omp::ReductionDeclareOp>(parentOp)) {
+      // ReductionDeclareOp has multiple child regions. We want to get the first
+      // block of whichever of those regions we are currently in
+      mlir::Region *parentRegion = rewriter.getInsertionBlock()->getParent();
+      rewriter.setInsertionPointToStart(&parentRegion->front());
+    } else {
+      mlir::Block *insertBlock = getBlockForAllocaInsert(parentOp);
+      rewriter.setInsertionPointToStart(insertBlock);
+    }
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tblah wrote:

That function doesn't have access to the rewriter. I could have added it as an argument, but I felt that it reads a bit weird there because it isn't obvious out of context what the conditions on the rewriter are.

The awkwardness comes from the use of multiple regions in the reduction declare op. We need to make sure the alloca ends up in the same region that we are currently inserting into.

https://github.com/llvm/llvm-project/pull/84952