[llvm] r372125 - Revert "[SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y)"

[Krasimir Georgiev via llvm-commits]

Author: krasimir
Date: Tue Sep 17 07:15:23 2019
New Revision: 372125

URL: http://llvm.org/viewvc/llvm-project?rev=372125&view=rev
Log:
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

Modified:
    llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
    llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=372125&r1=372124&r2=372125&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Tue Sep 17 07:15:23 2019
@@ -610,10 +610,7 @@ Value *LibCallSimplifier::optimizeStrNCp
 
   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;
   }
 

Modified: llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll?rev=372125&r1=372124&r2=372125&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll Tue Sep 17 07:15:23 2019
@@ -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() {