[llvm] [DSE] Remove `uninitialized` from `allockind` when creating dummy zeroed variant function (PR #149336)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: None (clubby789)

<details>
<summary>Changes</summary>

cc https://github.com/llvm/llvm-project/pull/138299

rustc sets `allockind("uninitialized")` - if we copy the attributes as-is when creating a dummy function, Verify complains about `allockind("uninitialized,zeroed")` conflicting, so we need to clear the flag.

---
Full diff: https://github.com/llvm/llvm-project/pull/149336.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp (+1) 
- (modified) llvm/test/Transforms/DeadStoreElimination/zeroed-missing.ll (+1-1) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index 85dd9a1bf7161..0f63ed0166cf4 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -2079,6 +2079,7 @@ struct DSEState {
       AllocFnKind AllocKind =
           Attrs.getFnAttr(Attribute::AllocKind).getAllocKind() |
           AllocFnKind::Zeroed;
+      AllocKind &= ~AllocFnKind::Uninitialized;
       Attrs =
           Attrs.addFnAttribute(Ctx, Attribute::getWithAllocKind(Ctx, AllocKind))
               .removeFnAttribute(Ctx, "alloc-variant-zeroed");
diff --git a/llvm/test/Transforms/DeadStoreElimination/zeroed-missing.ll b/llvm/test/Transforms/DeadStoreElimination/zeroed-missing.ll
index e390d4bdca632..303afc207c023 100644
--- a/llvm/test/Transforms/DeadStoreElimination/zeroed-missing.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/zeroed-missing.ll
@@ -12,6 +12,6 @@ define ptr @undeclared_customalloc(i64 %size, i64 %align) {
   ret ptr %call
 }
 
-declare ptr @customalloc2(i64, i64) allockind("alloc") "alloc-family"="customalloc2" "alloc-variant-zeroed"="customalloc2_zeroed"
+declare ptr @customalloc2(i64, i64) allockind("alloc,uninitialized") "alloc-family"="customalloc2" "alloc-variant-zeroed"="customalloc2_zeroed"
 ; CHECK-DAG: declare ptr @customalloc2_zeroed(i64, i64) #[[CA2ATTR:[0-9]+]]
 ; CHECK-DAG: attributes #[[CA2ATTR]] = { allockind("alloc,zeroed") "alloc-family"="customalloc2" }

``````````

</details>


https://github.com/llvm/llvm-project/pull/149336