[FuncAttrs] Don't infer noundef for functions with sanitize_memory attribute#76691
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[FuncAttrs] Don't infer noundef for functions with sanitize_memory attribute#76691
noundef for functions with sanitize_memory attribute#76691Conversation
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@llvm/pr-subscribers-llvm-transforms Author: Yingwei Zheng (dtcxzyw) ChangesMemorySanitizer assumes that the definition and declaration of a function will be consistent. If we add Fix buildbot failure caused by #76553. Full diff: https://github.com/llvm/llvm-project/pull/76691.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index ce083979afc63a..7ebf265e17ba1f 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -1296,6 +1296,12 @@ static void addNoUndefAttrs(const SCCNodeSet &SCCNodes,
if (!F->hasExactDefinition())
return;
+ // MemorySanitizer assumes that the definition and declaration of a
+ // function will be consistent. A function with sanitize_memory attribute
+ // should be skipped from inference.
+ if (F->hasFnAttribute(Attribute::SanitizeMemory))
+ continue;
+
if (F->getReturnType()->isVoidTy())
continue;
diff --git a/llvm/test/Transforms/FunctionAttrs/noundef.ll b/llvm/test/Transforms/FunctionAttrs/noundef.ll
index b357587cc12394..946b562f39553e 100644
--- a/llvm/test/Transforms/FunctionAttrs/noundef.ll
+++ b/llvm/test/Transforms/FunctionAttrs/noundef.ll
@@ -143,3 +143,12 @@ define i32 @test_noundef_prop() {
%ret = call i32 @test_ret_constant()
ret i32 %ret
}
+
+; Don't deduce noundef for functions with sanitize_memory.
+define i32 @test_ret_constant_msan() sanitize_memory {
+; CHECK-LABEL: define i32 @test_ret_constant_msan(
+; CHECK-SAME: ) #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT: ret i32 0
+;
+ ret i32 0
+}
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nikic
approved these changes
Jan 1, 2024
| @@ -1296,6 +1296,12 @@ static void addNoUndefAttrs(const SCCNodeSet &SCCNodes, | |||
| if (!F->hasExactDefinition()) | |||
| return; | |||
Contributor
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Unrelated to this PR, but I think this should be continue rather than return as well.
Collaborator
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Thank you! Probably we can skip only not internal/private linkage, but I don't think performance improvement will be meaningful for msan, So as is LGTM for simplicity. |
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MemorySanitizer assumes that the definition and declaration of a function will be consistent. If we add
noundeffor some definitions, it will break msan.Fix buildbot failure caused by #76553.