Add a doesAccessArgPointees helper function, and update code to use

it, and to be consistent.

llvm-svn: 118692

3 files changed, 33 insertions, 23 deletions

diff --git a/llvm/include/llvm/Analysis/AliasAnalysis.h b/llvm/include/llvm/Analysis/AliasAnalysis.h
index 12b2090b174..5a1c53cd1fa 100644
--- a/llvm/include/llvm/Analysis/AliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/AliasAnalysis.h
@@ -283,6 +283,14 @@ public:
     return !(MRB & Anywhere & ~ArgumentPointees);
   }
 
+  /// doesAccessArgPointees - Return true if functions with the specified
+  /// behavior are known to potentially read or write  from objects pointed
+  /// to be their pointer-typed arguments (with arbitrary offsets).
+  ///
+  static bool doesAccessArgPointees(ModRefBehavior MRB) {
+    return (MRB & ModRef) && (MRB & 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/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 363da9fcee6..9c0bded3721 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -78,15 +78,15 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS,
   if (onlyReadsMemory(MRB))
     Mask = Ref;
 
-  if (MRB == AccessesArguments ||
-      MRB == AccessesArgumentsReadonly) {
+  if (onlyAccessesArgPointees(MRB)) {
     bool doesAlias = false;
-    for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
-         AI != AE; ++AI)
-      if (!isNoAlias(Location(*AI), Loc)) {
-        doesAlias = true;
-        break;
-      }
+    if (doesAccessArgPointees(MRB))
+      for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+           AI != AE; ++AI)
+        if (!isNoAlias(Location(*AI), Loc)) {
+          doesAlias = true;
+          break;
+        }
 
     if (!doesAlias)
       return NoModRef;
@@ -130,27 +130,29 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) {
   // If CS2 only access memory through arguments, accumulate the mod/ref
   // information from CS1's references to the memory referenced by
   // CS2's arguments.
-  if (CS2B == AccessesArguments || CS2B == AccessesArgumentsReadonly) {
+  if (onlyAccessesArgPointees(CS2B)) {
     AliasAnalysis::ModRefResult R = NoModRef;
-    for (ImmutableCallSite::arg_iterator
-         I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) {
-      R = ModRefResult((R | getModRefInfo(CS1, *I, UnknownSize)) & Mask);
-      if (R == Mask)
-        break;
-    }
+    if (doesAccessArgPointees(CS2B))
+      for (ImmutableCallSite::arg_iterator
+           I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) {
+        R = ModRefResult((R | getModRefInfo(CS1, *I, UnknownSize)) & Mask);
+        if (R == Mask)
+          break;
+      }
     return R;
   }
 
   // If CS1 only accesses memory through arguments, check if CS2 references
   // any of the memory referenced by CS1's arguments. If not, return NoModRef.
-  if (CS1B == AccessesArguments || CS1B == AccessesArgumentsReadonly) {
+  if (onlyAccessesArgPointees(CS1B)) {
     AliasAnalysis::ModRefResult R = NoModRef;
-    for (ImmutableCallSite::arg_iterator
-         I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I)
-      if (getModRefInfo(CS2, *I, UnknownSize) != NoModRef) {
-        R = Mask;
-        break;
-      }
+    if (doesAccessArgPointees(CS1B))
+      for (ImmutableCallSite::arg_iterator
+           I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I)
+        if (getModRefInfo(CS2, *I, UnknownSize) != NoModRef) {
+          R = Mask;
+          break;
+        }
     if (R == NoModRef)
       return R;
   }
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 2e3440066e6..bb3ee465716 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -133,7 +133,7 @@ bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) {
         // figure out something.
         if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
           // If the call does access argument pointees, check each argument.
-          if (MRB & AliasAnalysis::AccessesArguments)
+          if (AliasAnalysis::doesAccessArgPointees(MRB))
             // Check whether all pointer arguments point to local memory, and
             // ignore calls that only access local memory.
             for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();