X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FTypeBasedAliasAnalysis.cpp;h=0faf1398ec76609775e1a05d91252f0e964d5d4b;hb=6c3541d5597033bdb2f26f5ade811b482c32a39a;hp=16ff64e4cfba33e3d4b2dc3e1d763fdb6580aa68;hpb=a8598bec287108d0359880d33955759dc90cd5a1;p=oota-llvm.git

diff --git a/lib/Analysis/TypeBasedAliasAnalysis.cpp b/lib/Analysis/TypeBasedAliasAnalysis.cpp
index 16ff64e4cfb..0faf1398ec7 100644
--- a/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -31,7 +31,7 @@
 //
 // The second field identifies the type's parent node in the tree, or
 // is null or omitted for a root node. A type is considered to alias
-// all of its decendents and all of its ancestors in the tree. Also,
+// all of its descendants and all of its ancestors in the tree. Also,
 // a type is considered to alias all types in other trees, so that
 // bitcode produced from multiple front-ends is handled conservatively.
 //
@@ -59,6 +59,7 @@
 
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/Passes.h"
+#include "llvm/Constants.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Module.h"
 #include "llvm/Metadata.h"
@@ -66,8 +67,10 @@
 #include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
-// For testing purposes, enable TBAA only via a special option.
-static cl::opt<bool> EnableTBAA("enable-tbaa");
+// A handy option for disabling TBAA functionality. The same effect can also be
+// achieved by stripping the !tbaa tags from IR, but this option is sometimes
+// more convenient.
+static cl::opt<bool> EnableTBAA("enable-tbaa", cl::init(true));
 
 namespace {
   /// TBAANode - This is a simple wrapper around an MDNode which provides a
@@ -256,11 +259,12 @@ TypeBasedAliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
     if (TBAANode(M).TypeIsImmutable())
       Min = OnlyReadsMemory;
 
-  return std::min(AliasAnalysis::getModRefBehavior(CS), Min);
+  return ModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min);
 }
 
 AliasAnalysis::ModRefBehavior
 TypeBasedAliasAnalysis::getModRefBehavior(const Function *F) {
+  // Functions don't have metadata. Just chain to the next implementation.
   return AliasAnalysis::getModRefBehavior(F);
 }