[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
Chris Lattner
lattner at cs.uiuc.edu
Tue Jul 6 02:02:01 PDT 2004
Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.217 -> 1.218
---
Log message:
Implement InstCombine/sub.ll:test15: X % -Y === X % Y
Also, remove X % -1 = 0, because it's not true for unsigneds, and the
signed case is superceeded by this new handling.
---
Diffs of the changes: (+9 -2)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.217 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.218
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.217 Fri Jul 2 19:26:11 2004
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Tue Jul 6 02:01:22 2004
@@ -844,11 +844,18 @@
Instruction *InstCombiner::visitRem(BinaryOperator &I) {
+ if (I.getType()->isSigned())
+ if (Value *RHSNeg = dyn_castNegVal(I.getOperand(1)))
+ if (RHSNeg != I.getOperand(1)) { // Avoid problems with MININT
+ // X % -Y -> X % Y
+ AddUsesToWorkList(I);
+ I.setOperand(1, RHSNeg);
+ return &I;
+ }
+
if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) {
if (RHS->equalsInt(1)) // X % 1 == 0
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- if (RHS->isAllOnesValue()) // X % -1 == 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
// Check to see if this is an unsigned remainder with an exact power of 2,
// if so, convert to a bitwise and.
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