Revert r64460. strtol and friends cannot be marked readonly, even with
a null endptr argument, because they may write to errno.
This fixes a seflhost miscompile observed on Linux targets when TBAA
was enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122014 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 43c6f6d..3edc447 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -577,7 +577,8 @@
Value *EndPtr = CI->getArgOperand(1);
if (isa<ConstantPointerNull>(EndPtr)) {
- CI->setOnlyReadsMemory();
+ // With a null EndPtr, this function won't capture the main argument.
+ // It would be readonly too, except that it still may write to errno.
CI->addAttribute(1, Attribute::NoCapture);
}
diff --git a/test/Transforms/SimplifyLibCalls/2009-02-12-StrTo.ll b/test/Transforms/SimplifyLibCalls/2009-02-12-StrTo.ll
index cb9819c..f8a0c88 100644
--- a/test/Transforms/SimplifyLibCalls/2009-02-12-StrTo.ll
+++ b/test/Transforms/SimplifyLibCalls/2009-02-12-StrTo.ll
@@ -1,7 +1,7 @@
; RUN: opt < %s -simplify-libcalls -S > %t
; RUN: grep nocapture %t | count 2
; RUN: grep null %t | grep nocapture | count 1
-; RUN: grep null %t | grep call | grep readonly | count 1
+; RUN: grep null %t | grep call | not grep readonly
; Test that we add nocapture to the declaration, and to the second call only.