Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.558 -> 1.559
---
Log message:
add an instcombine xform. This speeds up 462.libquantum from 9.78s to
7.48s. This regression is due to unforseen consequences of the cast patch.
---
Diffs of the changes: (+17 -0)
InstructionCombining.cpp | 17 +++++++++++++++++
1 files changed, 17 insertions(+)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.558
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.559
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.558 Sun Dec 3
20:48:01 2006
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Mon Dec 4 19:26:29 2006
@@ -6023,6 +6023,23 @@
Value *V = InsertCastBefore(SrcI->getOperand(0), Ty, CI);
return new ShiftInst(Instruction::LShr, V, SrcI->getOperand(1));
}
+ } else { // This is a variable shr.
+
+ // Turn 'trunc (lshr X, Y) to bool' into '(X & (1 << Y)) != 0'. This
is
+ // more LLVM instructions, but allows '1 << Y' to be hoisted if
+ // loop-invariant and CSE'd.
+ if (CI.getType() == Type::BoolTy && SrcI->hasOneUse()) {
+ Value *One = ConstantInt::get(SrcI->getType(), 1);
+
+ Value *V = InsertNewInstBefore(new ShiftInst(Instruction::Shl, One,
+ SrcI->getOperand(1),
+ "tmp"), CI);
+ V = InsertNewInstBefore(BinaryOperator::createAnd(V,
+
SrcI->getOperand(0),
+ "tmp"), CI);
+ Value *Zero = Constant::getNullValue(V->getType());
+ return BinaryOperator::createSetNE(V, Zero);
+ }
}
break;
}
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