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Make some codes more efficient.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35297 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Zhou Sheng 2007-03-24 15:34:37 +00:00
parent 1a77a556cd
commit 00f436c5bc
1 changed files with 17 additions and 15 deletions
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32
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -3117,7 +3117,9 @@ Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
case Instruction::And:
if (ConstantExpr::getAnd(N, Mask) == Mask) {
// If the AndRHS is a power of two minus one (0+1+), this is simple.
if ((Mask->getValue() & Mask->getValue()+1) == 0)
if ((Mask->getValue().countLeadingZeros() +
Mask->getValue().countPopulation()) ==
Mask->getValue().getBitWidth())
break;
// Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
@ -3127,7 +3129,7 @@ Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
if (isRunOfOnes(Mask, MB, ME)) { // begin/end bit of run, inclusive
uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
APInt Mask(APInt::getAllOnesValue(BitWidth));
Mask = APIntOps::lshr(Mask, BitWidth-MB+1);
Mask = Mask.lshr(BitWidth-MB+1);
if (MaskedValueIsZero(RHS, Mask))
break;
}
@ -3136,8 +3138,9 @@ Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
case Instruction::Or:
case Instruction::Xor:
// If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
if ((Mask->getValue() & Mask->getValue()+1) == 0 &&
ConstantExpr::getAnd(N, Mask)->isNullValue())
if ((Mask->getValue().countLeadingZeros() +
Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
&& ConstantExpr::getAnd(N, Mask)->isNullValue())
break;
return 0;
}
@ -5731,8 +5734,8 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
// operation.
//
if (isValid && !isLeftShift && I.getOpcode() == Instruction::AShr) {
APInt Val(Op0C->getValue());
isValid = ((Val & APInt::getSignBit(TypeBits)) != 0) == highBitSet;
isValid = ((Op0C->getValue() & APInt::getSignBit(TypeBits)) != 0) ==
highBitSet;
}
if (isValid) {
@ -5757,7 +5760,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
ConstantInt *ShiftAmt1C = cast<ConstantInt>(ShiftOp->getOperand(1));
// shift amount always <= 32 bits
// These shift amounts are always <= 32 bits.
unsigned ShiftAmt1 = (unsigned)ShiftAmt1C->getZExtValue();
unsigned ShiftAmt2 = (unsigned)Op1->getZExtValue();
assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
@ -5785,7 +5788,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator::createAShr(X, ConstantInt::get(Ty, AmtSum));
InsertNewInstBefore(Shift, I);
APInt Mask(APInt::getAllOnesValue(TypeBits).lshr(ShiftAmt2));
APInt Mask(Ty->getMask().lshr(ShiftAmt2));
return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
}
@ -5794,12 +5797,12 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
if (ShiftAmt1 == ShiftAmt2) {
// If we have ((X >>? C) << C), turn this into X & (-1 << C).
if (I.getOpcode() == Instruction::Shl) {
APInt Mask(APInt::getAllOnesValue(TypeBits).shl(ShiftAmt1));
APInt Mask(Ty->getMask().shl(ShiftAmt1));
return BinaryOperator::createAnd(X, ConstantInt::get(Mask));
}
// If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
if (I.getOpcode() == Instruction::LShr) {
APInt Mask(APInt::getAllOnesValue(TypeBits).lshr(ShiftAmt1));
APInt Mask(Ty->getMask().lshr(ShiftAmt1));
return BinaryOperator::createAnd(X, ConstantInt::get(Mask));
}
// We can simplify ((X << C) >>s C) into a trunc + sext.
@ -5813,7 +5816,6 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
case 16 : SExtType = Type::Int16Ty; break;
case 32 : SExtType = Type::Int32Ty; break;
case 64 : SExtType = Type::Int64Ty; break;
case 128: SExtType = IntegerType::get(128); break;
default: break;
}
if (SExtType) {
@ -5833,7 +5835,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator::createShl(X, ConstantInt::get(Ty, ShiftDiff));
InsertNewInstBefore(Shift, I);
APInt Mask(APInt::getAllOnesValue(TypeBits).shl(ShiftAmt2));
APInt Mask(Ty->getMask().shl(ShiftAmt2));
return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
}
@ -5844,7 +5846,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator::createLShr(X, ConstantInt::get(Ty, ShiftDiff));
InsertNewInstBefore(Shift, I);
APInt Mask(APInt::getAllOnesValue(TypeBits).lshr(ShiftAmt2));
APInt Mask(Ty->getMask().lshr(ShiftAmt2));
return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
}
@ -5862,7 +5864,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
ConstantInt::get(Ty, ShiftDiff));
InsertNewInstBefore(Shift, I);
APInt Mask(APInt::getAllOnesValue(TypeBits).shl(ShiftAmt2));
APInt Mask(Ty->getMask().shl(ShiftAmt2));
return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
}
@ -5873,7 +5875,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator::createShl(X, ConstantInt::get(Ty, ShiftDiff));
InsertNewInstBefore(Shift, I);
APInt Mask(APInt::getAllOnesValue(TypeBits).lshr(ShiftAmt2));
APInt Mask(Ty->getMask().lshr(ShiftAmt2));
return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
}