From 432d08cbdb9ceaa333f1d6eab4f8b542fdddf9db Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Wed, 10 Nov 2010 17:34:04 +0000 Subject: [PATCH] Factor out the code for testing whether a function accesses arbitrary memory into a helper function, and adjust some comments. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118687 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/AliasAnalysis.h | 13 ++++++++++--- lib/Transforms/IPO/FunctionAttrs.cpp | 5 ++--- 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/llvm/Analysis/AliasAnalysis.h b/include/llvm/Analysis/AliasAnalysis.h index 6b716ddee94..12b2090b174 100644 --- a/include/llvm/Analysis/AliasAnalysis.h +++ b/include/llvm/Analysis/AliasAnalysis.h @@ -268,14 +268,21 @@ public: return onlyReadsMemory(getModRefBehavior(F)); } - /// onlyReadsMemory - If the functions with the specified behavior are known - /// to only read from non-volatile memory (or not access memory at all), return - /// true. For use when the call site is not known. + /// onlyReadsMemory - Return true if functions with the specified behavior are + /// known to only read from non-volatile memory (or not access memory at all). /// static bool onlyReadsMemory(ModRefBehavior MRB) { return !(MRB & Mod); } + /// onlyAccessesArgPointees - Return true if functions with the specified + /// behavior are known to read at most from objects pointed to by their + /// pointer-typed arguments (with arbitrary offsets). + /// + static bool onlyAccessesArgPointees(ModRefBehavior MRB) { + return !(MRB & Anywhere & ~ArgumentPointees); + } + /// getModRefInfo - Return information about whether or not an instruction may /// read or write the specified memory location. An instruction /// that doesn't read or write memory may be trivially LICM'd for example. diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp index 3b1b13d378f..2e3440066e6 100644 --- a/lib/Transforms/IPO/FunctionAttrs.cpp +++ b/lib/Transforms/IPO/FunctionAttrs.cpp @@ -131,9 +131,8 @@ bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) { AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(CS); // If the call doesn't access arbitrary memory, we may be able to // figure out something. - if (!(MRB & AliasAnalysis::Anywhere & - ~AliasAnalysis::ArgumentPointees)) { - // If the call accesses argument pointees, check each argument. + if (AliasAnalysis::onlyAccessesArgPointees(MRB)) { + // If the call does access argument pointees, check each argument. if (MRB & AliasAnalysis::AccessesArguments) // Check whether all pointer arguments point to local memory, and // ignore calls that only access local memory. -- 2.34.1