[llvm-branch-commits] [llvm] [AtomicExpand] Add bitcasts when expanding load atomic vector (PR #120716)

[Matt Arsenault via llvm-branch-commits]

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@@ -2060,9 +2060,28 @@ bool AtomicExpandImpl::expandAtomicOpToLibcall(
     I->replaceAllUsesWith(V);
   } else if (HasResult) {
     Value *V;
-    if (UseSizedLibcall)
-      V = Builder.CreateBitOrPointerCast(Result, I->getType());
-    else {
+    if (UseSizedLibcall) {
+      // Add bitcasts from Result's T scalar type to I's <2 x T/2> vector type
+      if (I->getType()->getScalarType()->isIntOrPtrTy() &&
+          I->getType()->isVectorTy() && !Result->getType()->isVectorTy()) {
+        TypeSize Size = Result->getType()->getPrimitiveSizeInBits();
+        assert((unsigned)Size % 2 == 0);
+        unsigned HalfSize = (unsigned)Size / 2;
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arsenm wrote:

bitcast i128 to <2 x ptr> and then inttoptr <2 x i64> to <2 x ptr>?

https://github.com/llvm/llvm-project/pull/120716