From 37ade2b8015d86e73c62ab48a2ce5f0ce10de708 Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Sun, 7 Jul 2013 10:15:16 +0000 Subject: Eliminate trivial redundant loads across nocapture+readonly calls to uncaptured pointer arguments. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185776 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/AliasAnalysis.cpp | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'lib') diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp index 3454ce0..054930c 100644 --- a/lib/Analysis/AliasAnalysis.cpp +++ b/lib/Analysis/AliasAnalysis.cpp @@ -450,6 +450,7 @@ AliasAnalysis::callCapturesBefore(const Instruction *I, return AliasAnalysis::ModRef; unsigned ArgNo = 0; + AliasAnalysis::ModRefResult R = AliasAnalysis::NoModRef; for (ImmutableCallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end(); CI != CE; ++CI, ++ArgNo) { // Only look at the no-capture or byval pointer arguments. If this @@ -463,12 +464,18 @@ AliasAnalysis::callCapturesBefore(const Instruction *I, // is impossible to alias the pointer we're checking. If not, we have to // assume that the call could touch the pointer, even though it doesn't // escape. - if (!isNoAlias(AliasAnalysis::Location(*CI), - AliasAnalysis::Location(Object))) { - return AliasAnalysis::ModRef; + if (isNoAlias(AliasAnalysis::Location(*CI), + AliasAnalysis::Location(Object))) + continue; + if (CS.doesNotAccessMemory(ArgNo)) + continue; + if (CS.onlyReadsMemory(ArgNo)) { + R = AliasAnalysis::Ref; + continue; } + return AliasAnalysis::ModRef; } - return AliasAnalysis::NoModRef; + return R; } // AliasAnalysis destructor: DO NOT move this to the header file for -- cgit v1.1