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Add another optimization from PR2330. Also catch some missing cases that are
similar. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53451 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -5480,6 +5480,45 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
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return R;
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return R;
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}
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}
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// See if it's the same type of instruction on the left and right.
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if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
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if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
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if (Op0I->getOpcode() == Op1I->getOpcode() && Op0I->hasOneUse() &&
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Op1I->hasOneUse() && Op0I->getOperand(1) == Op1I->getOperand(1) &&
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I.isEquality()) {
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switch (Op0I->getOpcode()) {
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default: break;
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case Instruction::Add:
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case Instruction::Sub:
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case Instruction::Xor:
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// a+x icmp eq/ne b+x --> a icmp b
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return new ICmpInst(I.getPredicate(), Op0I->getOperand(0),
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Op1I->getOperand(0));
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break;
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case Instruction::Mul:
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if (ConstantInt *CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
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// a * Cst icmp eq/ne b * Cst --> a & 0x7f icmp b & 0x7f
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if (!CI->isZero() && !CI->isOne()) {
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const APInt &AP = CI->getValue();
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ConstantInt *Mask = ConstantInt::get(
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APInt::getLowBitsSet(AP.getBitWidth(),
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AP.getBitWidth() -
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AP.countTrailingZeros()));
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Instruction *And1 = BinaryOperator::CreateAnd(Op0I->getOperand(0),
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Mask);
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Instruction *And2 = BinaryOperator::CreateAnd(Op1I->getOperand(0),
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Mask);
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InsertNewInstBefore(And1, I);
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InsertNewInstBefore(And2, I);
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return new ICmpInst(I.getPredicate(), And1, And2);
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}
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}
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break;
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}
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}
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}
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}
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// ~x < ~y --> y < x
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// ~x < ~y --> y < x
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{ Value *A, *B;
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{ Value *A, *B;
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if (match(Op0, m_Not(m_Value(A))) &&
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if (match(Op0, m_Not(m_Value(A))) &&
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19
test/Transforms/InstCombine/2008-07-10-ICmpBinOp.ll
Normal file
19
test/Transforms/InstCombine/2008-07-10-ICmpBinOp.ll
Normal file
@ -0,0 +1,19 @@
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep add
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep mul
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; PR2330
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define i1 @f(i32 %x, i32 %y) nounwind {
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entry:
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%A = add i32 %x, 5
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%B = add i32 %y, 5
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%C = icmp eq i32 %A, %B
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ret i1 %C
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}
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define i1 @g(i32 %x, i32 %y) nounwind {
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entry:
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%A = mul i32 %x, 5
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%B = mul i32 %y, 5
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%C = icmp eq i32 %A, %B
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ret i1 %C
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}
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