[clang] [llvm] [llvm][OpenMP][SPIRV] Fix assertion for GPU reductions (PR #194879)

[Nick Sarnie via llvm-commits]

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@@ -4731,12 +4731,22 @@ OpenMPIRBuilder::InsertPointOrErrorTy OpenMPIRBuilder::createReductionsGPU(
                                              &LHSPtr, &RHSPtr, CurFunc));
 
       // Fix the CallBack code genereated to use the correct Values for the LHS
-      // and RHS
-      LHSPtr->replaceUsesWithIf(RedValue, [ReductionFunc](const Use &U) {
+      // and RHS. Cast to match types before replacing (necessary to handle
+      // different address spaces).
+      Value *CastRedValue = RedValue;
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sarnex wrote:

instead of making a new `CastRedValue` i wonder if it's cleaner to just overwrite the existing variable since i don't think we need it

`if(...) {
RedValue = Builder.Create...(RedValue, ...)
...
}

https://github.com/llvm/llvm-project/pull/194879