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[InstCombine] Simplify 1/X for vectors.

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llvm-svn: 300439
This commit is contained in:
Craig Topper 2017-04-17 03:41:47 +00:00
parent eee53c030a
commit 218a359fbd
2 changed files with 20 additions and 18 deletions
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31
llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
View File

@ -944,22 +944,21 @@ Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
}
}
if (ConstantInt *One = dyn_cast<ConstantInt>(Op0)) {
if (One->isOne() && !I.getType()->isIntegerTy(1)) {
bool isSigned = I.getOpcode() == Instruction::SDiv;
if (isSigned) {
// If Op1 is 0 then it's undefined behaviour, if Op1 is 1 then the
// result is one, if Op1 is -1 then the result is minus one, otherwise
// it's zero.
Value *Inc = Builder->CreateAdd(Op1, One);
Value *Cmp = Builder->CreateICmpULT(
Inc, ConstantInt::get(I.getType(), 3));
return SelectInst::Create(Cmp, Op1, ConstantInt::get(I.getType(), 0));
} else {
// If Op1 is 0 then it's undefined behaviour. If Op1 is 1 then the
// result is one, otherwise it's zero.
return new ZExtInst(Builder->CreateICmpEQ(Op1, One), I.getType());
}
if (match(Op0, m_One())) {
assert(!I.getType()->getScalarType()->isIntegerTy(1) &&
"i1 divide not removed?");
if (I.getOpcode() == Instruction::SDiv) {
// If Op1 is 0 then it's undefined behaviour, if Op1 is 1 then the
// result is one, if Op1 is -1 then the result is minus one, otherwise
// it's zero.
Value *Inc = Builder->CreateAdd(Op1, Op0);
Value *Cmp = Builder->CreateICmpULT(
Inc, ConstantInt::get(I.getType(), 3));
return SelectInst::Create(Cmp, Op1, ConstantInt::get(I.getType(), 0));
} else {
// If Op1 is 0 then it's undefined behaviour. If Op1 is 1 then the
// result is one, otherwise it's zero.
return new ZExtInst(Builder->CreateICmpEQ(Op1, Op0), I.getType());
}
}

7
llvm/test/Transforms/InstCombine/div.ll
View File

@ -227,7 +227,8 @@ define i32 @test19(i32 %x) {
define <2 x i32> @test19vec(<2 x i32> %x) {
; CHECK-LABEL: @test19vec(
; CHECK-NEXT: [[A:%.*]] = udiv <2 x i32> <i32 1, i32 1>, [[X:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <2 x i32> [[X:%.*]], <i32 1, i32 1>
; CHECK-NEXT: [[A:%.*]] = zext <2 x i1> [[TMP1]] to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[A]]
;
%A = udiv <2 x i32> <i32 1, i32 1>, %x
@ -247,7 +248,9 @@ define i32 @test20(i32 %x) {
define <2 x i32> @test20vec(<2 x i32> %x) {
; CHECK-LABEL: @test20vec(
; CHECK-NEXT: [[A:%.*]] = sdiv <2 x i32> <i32 1, i32 1>, [[X:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i32> [[X:%.*]], <i32 1, i32 1>
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult <2 x i32> [[TMP1]], <i32 3, i32 3>
; CHECK-NEXT: [[A:%.*]] = select <2 x i1> [[TMP2]], <2 x i32> [[X]], <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[A]]
;
%A = sdiv <2 x i32> <i32 1, i32 1>, %x