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Optimize pointer comparison into the typesafe form, now that the backends will

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handle them efficiently. This is the opposite direction of the transformation
we used to have here.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92418 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2010-01-02 15:25:44 +00:00
parent bef37376be
commit 546d63176e
2 changed files with 33 additions and 2 deletions
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22
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -4432,8 +4432,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
if (SimplifyDemandedInstructionBits(I))
return &I;
return &I;
if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
const APInt &AndRHSMask = AndRHS->getValue();
@ -7312,6 +7311,25 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
}
}
break;
case Instruction::Or: {
if (!ICI.isEquality() || !RHS->isNullValue() || !LHSI->hasOneUse())
break;
Value *P, *Q;
if (match(LHSI, m_Or(m_PtrToInt(m_Value(P)), m_PtrToInt(m_Value(Q))))) {
// Simplify icmp eq (or (ptrtoint P), (ptrtoint Q)), 0
// -> and (icmp eq P, null), (icmp eq Q, null).
Value *ICIP = Builder->CreateICmp(ICI.getPredicate(), P,
Constant::getNullValue(P->getType()));
Value *ICIQ = Builder->CreateICmp(ICI.getPredicate(), Q,
Constant::getNullValue(Q->getType()));
Instruction *And = BinaryOperator::CreateAnd(ICIP, ICIQ, "");
And->takeName(&ICI);
return And;
}
break;
}
case Instruction::Shl: { // (icmp pred (shl X, ShAmt), CI)
ConstantInt *ShAmt = dyn_cast<ConstantInt>(LHSI->getOperand(1));

13
test/Transforms/InstCombine/or.ll
View File

@ -268,6 +268,19 @@ define i1 @test26(i32 %A, i32 %B) {
; CHECK: ret i1
}
define i1 @test27(i32* %A, i32* %B) {
%C1 = ptrtoint i32* %A to i32
%C2 = ptrtoint i32* %B to i32
%D = or i32 %C1, %C2
%E = icmp eq i32 %D, 0
ret i1 %E
; CHECK: @test27
; CHECK: icmp eq i32* %A, null
; CHECK: icmp eq i32* %B, null
; CHECK: and i1
; CHECK: ret i1
}
; PR5634
define i1 @test28(i32 %A, i32 %B) {
%C1 = icmp ne i32 %A, 0