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

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.192 -> 1.193

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Log message:

Instcombine X/-1 --> 0-X


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Diffs of the changes:  (+5 -1)

Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.192 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.193
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.192	Sat Apr 17 13:16:10 2004
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp	Mon Apr 26 09:01:59 2004
@@ -849,10 +849,14 @@
 }
 
 Instruction *InstCombiner::visitDiv(BinaryOperator &I) {
-  // div X, 1 == X
   if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) {
+    // div X, 1 == X
     if (RHS->equalsInt(1))
       return ReplaceInstUsesWith(I, I.getOperand(0));
+
+    // div X, -1 == -X
+    if (RHS->isAllOnesValue())
+      return BinaryOperator::createNeg(I.getOperand(0));
 
     // Check to see if this is an unsigned division with an exact power of 2,
     // if so, convert to a right shift.