forked from OSchip/llvm-project
Eliminate a bitwise 'not' op of 'not' min/max by inverting the min/max.
Bitwise 'not' of the min/max could be eliminated in the pattern: %notx = xor i32 %x, -1 %cmp1 = icmp sgt[slt/ugt/ult] i32 %notx, %y %smax = select i1 %cmp1, i32 %notx, i32 %y %res = xor i32 %smax, -1 https://rise4fun.com/Alive/lCN Reviewers: spatel Reviewed by: spatel Subscribers: a.elovikov, llvm-commits Differential Revision: https://reviews.llvm.org/D45317 llvm-svn: 329791
This commit is contained in:
Artur Gainullin
parent
057f5a1259
commit
d928201ac5
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@ -2696,5 +2696,35 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
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return SelectInst::Create(Cmp, Builder.CreateNeg(A), A);
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}
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// Eliminate a bitwise 'not' op of 'not' min/max by inverting the min/max:
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//
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// %notx = xor i32 %x, -1
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// %cmp1 = icmp sgt i32 %notx, %y
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// %smax = select i1 %cmp1, i32 %notx, i32 %y
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// %res = xor i32 %smax, -1
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// =>
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// %noty = xor i32 %y, -1
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// %cmp2 = icmp slt %x, %noty
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// %res = select i1 %cmp2, i32 %x, i32 %noty
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//
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// Same is applicable for smin/umax/umin.
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{
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Value *LHS, *RHS;
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SelectPatternFlavor SPF = matchSelectPattern(Op0, LHS, RHS).Flavor;
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if (Op0->hasOneUse() && SelectPatternResult::isMinOrMax(SPF) &&
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match(Op1, m_AllOnes())) {
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Value *X;
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if (match(RHS, m_Not(m_Value(X))))
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std::swap(RHS, LHS);
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if (match(LHS, m_Not(m_Value(X)))) {
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Value *NotY = Builder.CreateNot(RHS);
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return SelectInst::Create(
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Builder.CreateICmp(getInverseMinMaxPred(SPF), X, NotY), X, NotY);
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}
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}
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}
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return Changed ? &I : nullptr;
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}
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@ -238,10 +238,9 @@ define i32 @compute_min_pessimization(i32 %x, i32 %y) {
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; CHECK-LABEL: @compute_min_pessimization(
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; CHECK-NEXT: [[NOT_VALUE:%.*]] = sub i32 3, [[X:%.*]]
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; CHECK-NEXT: call void @fake_use(i32 [[NOT_VALUE]])
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; CHECK-NEXT: [[NOT_Y:%.*]] = xor i32 [[Y:%.*]], -1
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; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[NOT_VALUE]], [[NOT_Y]]
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; CHECK-NEXT: [[NOT_MIN:%.*]] = select i1 [[CMP]], i32 [[NOT_VALUE]], i32 [[NOT_Y]]
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; CHECK-NEXT: [[MIN:%.*]] = xor i32 [[NOT_MIN]], -1
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X]], -4
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; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[TMP1]], [[Y:%.*]]
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; CHECK-NEXT: [[MIN:%.*]] = select i1 [[TMP2]], i32 [[Y]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[MIN]]
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;
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%not_value = sub i32 3, %x
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@ -575,3 +575,147 @@ define i32 @test38(i32 %A, i32 %B) {
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%xor = xor i32 %and, %B
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ret i32 %xor
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}
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; The tests 39-47 are related to the canonicalization:
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; %notx = xor i32 %x, -1
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; %cmp = icmp sgt i32 %notx, %y
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; %smax = select i1 %cmp, i32 %notx, i32 %y
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; %res = xor i32 %smax, -1
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; =>
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; %noty = xor i32 %y, -1
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; %cmp2 = icmp slt %x, %noty
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; %res = select i1 %cmp2, i32 %x, i32 %noty
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;
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; Same transformations is valid for smin/umax/umin.
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define i32 @test39(i32 %x) {
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; CHECK-LABEL: @test39(
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; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 255
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 255
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%1 = xor i32 %x, -1
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%2 = icmp sgt i32 %1, -256
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%3 = select i1 %2, i32 %1, i32 -256
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%res = xor i32 %3, -1
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ret i32 %res
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}
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define i32 @test40(i32 %x, i32 %y) {
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; CHECK-LABEL: @test40(
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; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[Y:%.*]], -1
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; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[TMP1]], [[X:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%notx = xor i32 %x, -1
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%cmp1 = icmp sgt i32 %notx, %y
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%smax = select i1 %cmp1, i32 %notx, i32 %y
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%res = xor i32 %smax, -1
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ret i32 %res
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}
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define i32 @test41(i32 %x, i32 %y) {
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; CHECK-LABEL: @test41(
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; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[Y:%.*]], -1
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; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[TMP1]], [[X:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%notx = xor i32 %x, -1
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%cmp1 = icmp slt i32 %notx, %y
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%smin = select i1 %cmp1, i32 %notx, i32 %y
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%res = xor i32 %smin, -1
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ret i32 %res
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}
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define i32 @test42(i32 %x, i32 %y) {
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; CHECK-LABEL: @test42(
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; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[Y:%.*]], -1
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ugt i32 [[TMP1]], [[X:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%notx = xor i32 %x, -1
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%cmp1 = icmp ugt i32 %notx, %y
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%umax = select i1 %cmp1, i32 %notx, i32 %y
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%res = xor i32 %umax, -1
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ret i32 %res
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}
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define i32 @test43(i32 %x, i32 %y) {
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; CHECK-LABEL: @test43(
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; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[Y:%.*]], -1
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], [[X:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%notx = xor i32 %x, -1
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%cmp1 = icmp ult i32 %notx, %y
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%umin = select i1 %cmp1, i32 %notx, i32 %y
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%res = xor i32 %umin, -1
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ret i32 %res
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}
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define i32 @test44(i32 %x, i32 %y) {
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; CHECK-LABEL: @test44(
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; CHECK-NEXT: [[TMP1:%.*]] = sub i32 -4, [[Y:%.*]]
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], [[X:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 [[TMP1]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%z = add i32 %y, 3 ; thwart complexity-based canonicalization
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%notx = xor i32 %x, -1
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%cmp1 = icmp ult i32 %z, %notx
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%umin = select i1 %cmp1, i32 %z, i32 %notx
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%res = xor i32 %umin, -1
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ret i32 %res
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}
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define i32 @test45(i32 %x, i32 %y) {
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; CHECK-LABEL: @test45(
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; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i32 [[Y:%.*]], [[X:%.*]]
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; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[Y]], i32 [[X]]
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; CHECK-NEXT: ret i32 [[TMP2]]
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;
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%z = xor i32 %y, -1
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%notx = xor i32 %x, -1
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%cmp1 = icmp ult i32 %z, %notx
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%umin = select i1 %cmp1, i32 %z, i32 %notx
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%res = xor i32 %umin, -1
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ret i32 %res
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}
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; Check that we work with splat vectors also.
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define <4 x i32> @test46(<4 x i32> %x) {
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; CHECK-LABEL: @test46(
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; CHECK-NEXT: [[TMP1:%.*]] = icmp slt <4 x i32> [[X:%.*]], <i32 255, i32 255, i32 255, i32 255>
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; CHECK-NEXT: [[TMP2:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[X]], <4 x i32> <i32 255, i32 255, i32 255, i32 255>
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; CHECK-NEXT: ret <4 x i32> [[TMP2]]
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;
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%1 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 -1, i32 -1>
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%2 = icmp sgt <4 x i32> %1, <i32 -256, i32 -256, i32 -256, i32 -256>
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%3 = select <4 x i1> %2, <4 x i32> %1, <4 x i32> <i32 -256, i32 -256, i32 -256, i32 -256>
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%4 = xor <4 x i32> %3, <i32 -1, i32 -1, i32 -1, i32 -1>
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ret <4 x i32> %4
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}
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; Test case when select pattern has more than one use.
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define i32 @test47(i32 %x, i32 %y, i32 %z) {
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; CHECK-LABEL: @test47(
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; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt i32 [[NOTX]], [[Y:%.*]]
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; CHECK-NEXT: [[UMAX:%.*]] = select i1 [[CMP1]], i32 [[NOTX]], i32 [[Y]]
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; CHECK-NEXT: [[UMIN:%.*]] = xor i32 [[UMAX]], -1
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[UMAX]], [[Z:%.*]]
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; CHECK-NEXT: [[RES:%.*]] = mul i32 [[ADD]], [[UMIN]]
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; CHECK-NEXT: ret i32 [[RES]]
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;
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%notx = xor i32 %x, -1
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%cmp1 = icmp ugt i32 %notx, %y
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%umax = select i1 %cmp1, i32 %notx, i32 %y
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%umin = xor i32 %umax, -1
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%add = add i32 %umax, %z
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%res = mul i32 %umin, %add
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ret i32 %res
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}
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