From d15afd36388f0ee77e85e74e53ac1ebc52a1b5dc Mon Sep 17 00:00:00 2001 From: David Bolvansky Date: Tue, 17 Sep 2019 10:25:38 +0000 Subject: [PATCH] [SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372101 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyLibCalls.cpp | 5 ++++- test/Transforms/InstCombine/strncpy-1.ll | 10 ++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp index 217f929e9ad..a5e31f21166 100644 --- a/lib/Transforms/Utils/SimplifyLibCalls.cpp +++ b/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/test/Transforms/InstCombine/strncpy-1.ll b/test/Transforms/InstCombine/strncpy-1.ll index 38e8cfedba2..969358eb4d7 100644 --- a/test/Transforms/InstCombine/strncpy-1.ll +++ b/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() { -- 2.40.0