[llvm-commits] [llvm] r118687 - in /llvm/trunk: include/llvm/Analysis/AliasAnalysis.h lib/Transforms/IPO/FunctionAttrs.cpp

[Dan Gohman]

Author: djg
Date: Wed Nov 10 11:34:04 2010
New Revision: 118687

URL: http://llvm.org/viewvc/llvm-project?rev=118687&view=rev
Log:
Factor out the code for testing whether a function accesses
arbitrary memory into a helper function, and adjust some comments.

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

Modified: llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/AliasAnalysis.h?rev=118687&r1=118686&r2=118687&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/AliasAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/AliasAnalysis.h Wed Nov 10 11:34:04 2010
@@ -268,14 +268,21 @@
     return onlyReadsMemory(getModRefBehavior(F));
   }
 
-  /// onlyReadsMemory - If the functions with the specified behavior are known
-  /// to only read from non-volatile memory (or not access memory at all), return
-  /// true.  For use when the call site is not known.
+  /// onlyReadsMemory - Return true if functions with the specified behavior are
+  /// known to only read from non-volatile memory (or not access memory at all).
   ///
   static bool onlyReadsMemory(ModRefBehavior MRB) {
     return !(MRB & Mod);
   }
 
+  /// onlyAccessesArgPointees - Return true if functions with the specified
+  /// behavior are known to read at most from objects pointed to by their
+  /// pointer-typed arguments (with arbitrary offsets).
+  ///
+  static bool onlyAccessesArgPointees(ModRefBehavior MRB) {
+    return !(MRB & Anywhere & ~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.

Modified: llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp?rev=118687&r1=118686&r2=118687&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp Wed Nov 10 11:34:04 2010
@@ -131,9 +131,8 @@
         AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(CS);
         // If the call doesn't access arbitrary memory, we may be able to
         // figure out something.
-        if (!(MRB & AliasAnalysis::Anywhere &
-              ~AliasAnalysis::ArgumentPointees)) {
-          // If the call accesses argument pointees, check each argument.
+        if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
+          // If the call does access argument pointees, check each argument.
           if (MRB & AliasAnalysis::AccessesArguments)
             // Check whether all pointer arguments point to local memory, and
             // ignore calls that only access local memory.