From ae708a3d91a9babfa171760f15d0fdcedd674d0d Mon Sep 17 00:00:00 2001 From: Owen Anderson Date: Mon, 18 Feb 2008 03:52:21 +0000 Subject: [PATCH] Fix a comment, and a bug where we weren't applying the tail call logic in cases that failed the first test. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47253 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/BasicAliasAnalysis.cpp | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index b19ce2b8c48..c4153b93718 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -252,19 +252,21 @@ BasicAliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) { if (Object && (isa(Object) || isa(Object))) { // Okay, the pointer is to a stack allocated (or effectively so, for - // for noalias parameters) object. If we can prove that - // the pointer never "escapes", then we know the call cannot clobber it, - // because it simply can't get its address. + // for noalias parameters) object. If the address of this object doesn't + // escape from this function body to a callee, then we know that no + // callees can mod/ref it unless they are actually passed it. if (isa(Object) || cast(Object)->hasByValAttr() || cast(Object)->hasNoAliasAttr()) if (!AddressMightEscape(Object)) { + bool passedAsArg = false; for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end(); CI != CE; ++CI) if (getUnderlyingObject(CI->get()) == P) - return AliasAnalysis::getModRefInfo(CS, P, Size); - - return NoModRef; + passedAsArg = true; + + if (!passedAsArg) + return NoModRef; } // If this is a tail call and P points to a stack location, we know that -- 2.11.0