From 762e8e846f0ad50ffea56216c5ea20db1c95b756 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 30 Jan 2004 22:15:41 +0000 Subject: [PATCH] Add a new pointsToConstantMemory method to the AliasAnalysis interface which can be implemented to improve the quality of mod-ref information. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11020 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/AliasAnalysis.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/llvm/Analysis/AliasAnalysis.h b/include/llvm/Analysis/AliasAnalysis.h index b0e9b23ab18..9b5d8ff037f 100644 --- a/include/llvm/Analysis/AliasAnalysis.h +++ b/include/llvm/Analysis/AliasAnalysis.h @@ -95,6 +95,11 @@ public: /// virtual void getMustAliases(Value *P, std::vector &RetVals) {} + /// pointsToConstantMemory - If the specified pointer is known to point into + /// constant global memory, return true. This allows disambiguation of store + /// instructions from constant pointers. + /// + virtual bool pointsToConstantMemory(const Value *P) { return false; } //===--------------------------------------------------------------------===// /// Simple mod/ref information... @@ -114,7 +119,9 @@ public: /// pointer. /// virtual ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) { - return ModRef; + // If P points to a constant memory location, the call definitely could not + // modify the memory location. + return pointsToConstantMemory(P) ? Ref : ModRef; } /// getModRefInfo - Return information about whether two call sites may refer -- 2.34.1