[llvm] r234814 - Add new getModRefInfo API to determine whether an Instruction and a call modify the same memory

[Daniel Berlin]

Author: dannyb
Date: Mon Apr 13 18:25:41 2015
New Revision: 234814

URL: http://llvm.org/viewvc/llvm-project?rev=234814&view=rev
Log:
Add new getModRefInfo API to determine whether an Instruction and a call modify the same memory

Modified:
    llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
    llvm/trunk/lib/Analysis/AliasAnalysis.cpp

Modified: llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/AliasAnalysis.h?rev=234814&r1=234813&r2=234814&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/AliasAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/AliasAnalysis.h Mon Apr 13 18:25:41 2015
@@ -503,6 +503,10 @@ public:
   ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, uint64_t Size){
     return getModRefInfo(I, Location(P, Size));
   }
+  /// getModRefInfo - Return information about whether a call and an instruction
+  /// may refer to the same memory locations.
+  ModRefResult getModRefInfo(Instruction *I,
+                             ImmutableCallSite Call);
 
   /// getModRefInfo - Return information about whether two call sites may refer
   /// to the same set of memory locations.  See 

Modified: llvm/trunk/lib/Analysis/AliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasAnalysis.cpp?rev=234814&r1=234813&r2=234814&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasAnalysis.cpp Mon Apr 13 18:25:41 2015
@@ -82,6 +82,23 @@ void AliasAnalysis::addEscapingUse(Use &
   AA->addEscapingUse(U);
 }
 
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(Instruction *I, ImmutableCallSite Call) {
+  // We may have two calls
+  if (auto CS = ImmutableCallSite(I)) {
+    // Check if the two calls modify the same memory
+    return getModRefInfo(Call, CS);
+  } else {
+    // Otherwise, check if the call modifies or references the
+    // location this memory access defines.  The best we can say
+    // is that if the call references what this instruction
+    // defines, it must be clobbered by this location.
+    const AliasAnalysis::Location DefLoc = AA->getLocation(I);
+    if (getModRefInfo(Call, DefLoc) != AliasAnalysis::NoModRef)
+      return AliasAnalysis::ModRef;
+  }
+  return AliasAnalysis::NoModRef;
+}
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(ImmutableCallSite CS,