[Mlir-commits] [mlir] [MLIR][LLVMIR] Fix inline byval alloca hoisting out of allocation scope (PR #185399)

[Christian Ulmann]

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@@ -603,10 +603,26 @@ static Value handleByValArgumentInit(OpBuilder &builder, Location loc,
   // Allocate the new value on the stack.
   Value allocaOp;
   {
-    // Since this is a static alloca, we can put it directly in the entry block,
-    // so they can be absorbed into the prologue/epilogue at code generation.
+    // Walk up from the call site to find the innermost AutomaticAllocationScope
+    // (e.g. an llvm.func or scf.forall). Placing the alloca at the entry block
+    // of that scope keeps it inside parallel regions rather than hoisting it
+    // out, while still landing at the function entry block for the common
+    // non-parallel case.
     OpBuilder::InsertionGuard insertionGuard(builder);
-    Block *entryBlock = &(*argument.getParentRegion()->begin());
+    Block *entryBlock = nullptr;
+    Block *cursor = builder.getInsertionBlock();
+    while (cursor) {
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Dinistro wrote:

Nit: `getParentWithTrait` might make this easier. 

https://github.com/llvm/llvm-project/pull/185399