[llvm] [AMDGPU] Fix a potential wrong return value indicating whether a pass modifies a function (PR #88197)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Shilei Tian (shiltian)

<details>
<summary>Changes</summary>

When the alloca is too big for vectorization, the function could have already
been modified in previous iteration of the `for` loop.


---
Full diff: https://github.com/llvm/llvm-project/pull/88197.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp (+1-1) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp b/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
index 6f3cdf54dceec7..c0846b123d1870 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
@@ -336,7 +336,7 @@ bool AMDGPUPromoteAllocaImpl::run(Function &F, bool PromoteToLDS) {
     if (AllocaCost > VectorizationBudget) {
       LLVM_DEBUG(dbgs() << "  Alloca too big for vectorization: " << *AI
                         << "\n");
-      return false;
+      return Changed;
     }
 
     if (tryPromoteAllocaToVector(*AI)) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/88197