[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.593 -> 1.594
---
Log message:

Fix Transforms/InstCombine/2007-01-13-ExtCompareMiscompile.ll, which is part
of PR1107: http://llvm.org/PR1107 


---
Diffs of the changes:  (+13 -3)

 InstructionCombining.cpp |   16 +++++++++++++---
 1 files changed, 13 insertions(+), 3 deletions(-)


Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.593 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.594
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.593	Fri Jan 12 01:05:14 2007
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp	Sat Jan 13 17:11:38 2007
@@ -5263,9 +5263,19 @@
     RHSCIOp = CI->getOperand(0);
     if (RHSCIOp->getType() != LHSCIOp->getType()) 
       return 0;
-    else
-      // Okay, just insert a compare of the reduced operands now!
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, RHSCIOp);
+    
+    // If the signedness of the two compares doesn't agree (i.e. one is a sext
+    // and the other is a zext), then we can't handle this.
+    if (CI->getOpcode() != LHSCI->getOpcode())
+      return 0;
+
+    // Likewise, if the signedness of the [sz]exts and the compare don't match, 
+    // then we can't handle this.
+    if (isSignedExt != isSignedCmp && !ICI.isEquality())
+      return 0;
+    
+    // Okay, just insert a compare of the reduced operands now!
+    return new ICmpInst(ICI.getPredicate(), LHSCIOp, RHSCIOp);
   }
 
   // If we aren't dealing with a constant on the RHS, exit early