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-rw-r--r--llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp5
-rw-r--r--llvm/test/Transforms/InstCombine/strncpy-1.ll10
2 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 217f929e9ad..a5e31f21166 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -610,7 +610,10 @@ Value *LibCallSimplifier::optimizeStrNCpy(CallInst *CI, IRBuilder<> &B) {
if (SrcLen == 0) {
// strncpy(x, "", y) -> memset(align 1 x, '\0', y)
- B.CreateMemSet(Dst, B.getInt8('\0'), Size, 1);
+ CallInst *NewCI = B.CreateMemSet(Dst, B.getInt8('\0'), Size, 1);
+ AttrBuilder ArgAttrs(CI->getAttributes().getParamAttributes(0));
+ NewCI->setAttributes(NewCI->getAttributes().addParamAttributes(
+ CI->getContext(), 0, ArgAttrs));
return Dst;
}
diff --git a/llvm/test/Transforms/InstCombine/strncpy-1.ll b/llvm/test/Transforms/InstCombine/strncpy-1.ll
index 38e8cfedba2..969358eb4d7 100644
--- a/llvm/test/Transforms/InstCombine/strncpy-1.ll
+++ b/llvm/test/Transforms/InstCombine/strncpy-1.ll
@@ -134,6 +134,16 @@ define i8* @test2(i8* %dst) {
ret i8* %ret
}
+define i8* @test3(i8* %dst, i32 %n) {
+; CHECK-LABEL: @test3(
+; CHECK-NEXT: call void @llvm.memset.p0i8.i32(i8* noalias nonnull align 1 dereferenceable(5) [[DST:%.*]], i8 0, i32 5, i1 false)
+; CHECK-NEXT: ret i8* [[DST]]
+;
+ %src = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
+ %ret = call i8* @strncpy(i8* noalias nonnull %dst, i8* nonnull %src, i32 5);
+ ret i8* %ret
+}
+
; Check cases that shouldn't be simplified.
define void @test_no_simplify1() {
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