[llvm-commits] [llvm] r44999 - /llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp

[Wojciech Matyjewicz]

Author: wmat
Date: Thu Dec 13 10:22:58 2007
New Revision: 44999

URL: http://llvm.org/viewvc/llvm-project?rev=44999&view=rev
Log:
Make these loops follow GetGEPOperands() behavior.
Let: %q = GEP %p, X, ...
If %p is a GEP, we can chase baseptr further, only if X==0.


Modified:
    llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=44999&r1=44998&r2=44999&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Thu Dec 13 10:22:58 2007
@@ -391,17 +391,19 @@
   if (isGEP(V1) && isGEP(V2)) {
     // Drill down into the first non-gep value, to test for must-aliasing of
     // the base pointers.
-    const Value *BasePtr1 = V1, *BasePtr2 = V2;
-    do {
-      BasePtr1 = cast<User>(BasePtr1)->getOperand(0);
-    } while (isGEP(BasePtr1) &&
-             cast<User>(BasePtr1)->getOperand(1) ==
-       Constant::getNullValue(cast<User>(BasePtr1)->getOperand(1)->getType()));
-    do {
-      BasePtr2 = cast<User>(BasePtr2)->getOperand(0);
-    } while (isGEP(BasePtr2) &&
-             cast<User>(BasePtr2)->getOperand(1) ==
-       Constant::getNullValue(cast<User>(BasePtr2)->getOperand(1)->getType()));
+    const User *G = cast<User>(V1);
+    while (isGEP(G->getOperand(0)) &&
+           G->getOperand(1) ==
+           Constant::getNullValue(G->getOperand(1)->getType()))
+      G = cast<User>(G->getOperand(0));
+    const Value *BasePtr1 = G->getOperand(0);
+
+    G = cast<User>(V2);
+    while (isGEP(G->getOperand(0)) &&
+           G->getOperand(1) ==
+           Constant::getNullValue(G->getOperand(1)->getType()))
+      G = cast<User>(G->getOperand(0));
+    const Value *BasePtr2 = G->getOperand(0);
 
     // Do the base pointers alias?
     AliasResult BaseAlias = alias(BasePtr1, ~0U, BasePtr2, ~0U);