From: Krasimir Georgiev <krasimir@google.com>
Date: Tue, 17 Sep 2019 14:15:23 +0000 (+0000)
Subject: Revert "[SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y)"
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d5f8516fb76157042848d5b84d581873c7e5edbc;p=llvm

Revert "[SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y)"

Summary:
This reverts commit r372101.

Causes ASAN build bot failures:

http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/14176
From http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/14176/steps/64-bit%20check-asan/logs/stdio:

```
[ RUN      ] AddressSanitizer.StrNCatOOBTest
/home/buildbots/ppc64be-sanitizer/sanitizer-ppc64be/build/llvm-project/compiler-rt/lib/asan/tests/asan_str_test.cpp:462: Failure
Death test: strncat(to - 1, from, 0)
    Result: failed to die.
```

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67658

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372125 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index a5e31f21166..217f929e9ad 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -610,10 +610,7 @@ Value *LibCallSimplifier::optimizeStrNCpy(CallInst *CI, IRBuilder<> &B) {
 
   if (SrcLen == 0) {
     // strncpy(x, "", y) -> memset(align 1 x, '\0', y)
-    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));
+    B.CreateMemSet(Dst, B.getInt8('\0'), Size, 1);
     return Dst;
   }
 
diff --git a/test/Transforms/InstCombine/strncpy-1.ll b/test/Transforms/InstCombine/strncpy-1.ll
index 969358eb4d7..38e8cfedba2 100644
--- a/test/Transforms/InstCombine/strncpy-1.ll
+++ b/test/Transforms/InstCombine/strncpy-1.ll
@@ -134,16 +134,6 @@ 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() {