[llvm-commits] CVS: llvm/lib/Analysis/AliasSetTracker.cpp

[Chris Lattner]

Changes in directory llvm/lib/Analysis:

AliasSetTracker.cpp updated: 1.23 -> 1.24

---
Log message:

Use context-sensitive alias analysis to avoid pessimization in clients of 
AliasSetTracker (dse and licm).  This implements 
DeadStoreElimination/context-sensitive.llx


---
Diffs of the changes:  (+23 -5)

Index: llvm/lib/Analysis/AliasSetTracker.cpp
diff -u llvm/lib/Analysis/AliasSetTracker.cpp:1.23 llvm/lib/Analysis/AliasSetTracker.cpp:1.24
--- llvm/lib/Analysis/AliasSetTracker.cpp:1.23	Mon Jul 26 00:50:23 2004
+++ llvm/lib/Analysis/AliasSetTracker.cpp	Mon Jul 26 21:20:26 2004
@@ -138,20 +138,38 @@
       return true;
 
   // Check the call sites list and invoke list...
-  if (!CallSites.empty())
-    // FIXME: this is pessimistic!
-    return true;
+  if (!CallSites.empty()) {
+    if (AA.hasNoModRefInfoForCalls())
+      return true;
+
+    for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+      if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size)
+                   != AliasAnalysis::NoModRef)
+        return true;
+  }
 
   return false;
 }
 
 bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
-  // FIXME: Use mod/ref information to prune this better!
   if (Function *F = CS.getCalledFunction())
     if (AA.doesNotAccessMemory(F))
       return false;
 
-  return true;
+  if (AA.hasNoModRefInfoForCalls())
+    return true;
+
+  for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+    if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef ||
+        AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef)
+      return true;
+
+  for (iterator I = begin(), E = end(); I != E; ++I)
+    if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) !=
+           AliasAnalysis::NoModRef)
+      return true;
+
+  return false;
 }