X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FInstruction.cpp;h=48c73a08400c076316c5247ac002c6ca8fd396fe;hb=fadb3f773e5ab171315761d151c1416921d25614;hp=39a895510ae27b4c2810127a54fca6c2d0c499e7;hpb=f00042a9990d90885a8f236ed0f6bf07902d1374;p=oota-llvm.git

diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 39a895510ae..48c73a08400 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/Type.h"
 #include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/Function.h"
 #include "llvm/Support/LeakDetector.h"
 using namespace llvm;
@@ -225,6 +226,25 @@ bool Instruction::isSameOperationAs(Instruction *I) const {
   return true;
 }
 
+/// mayWriteToMemory - Return true if this instruction may modify memory.
+///
+bool Instruction::mayWriteToMemory() const {
+  switch (getOpcode()) {
+  default: return false;
+  case Instruction::Free:
+  case Instruction::Store:
+  case Instruction::Invoke:
+  case Instruction::VAArg:
+    return true;
+  case Instruction::Call:
+    if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(this)) {
+      // If the intrinsic doesn't write memory, it is safe.
+    }
+    return true;
+  case Instruction::Load:
+    return cast<LoadInst>(this)->isVolatile();
+  }
+}
 
 /// isAssociative - Return true if the instruction is associative:
 ///