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[InstCombine] Canonicalize fcmp with inf (#80986)
This patch canonicalizes floating-point comparisons with inf: ``` fcmp olt X, +inf -> fcmp one X, +inf fcmp ole X, +inf -> fcmp ord X, 0 fcmp ogt X, +inf -> false fcmp oge X, +inf -> fcmp oeq X, +inf fcmp ult X, +inf -> fcmp une X, +inf fcmp ule X, +inf -> true fcmp ugt X, +inf -> fcmp uno X, 0 fcmp uge X, +inf -> fcmp ueq X, +inf fcmp olt X, -inf -> false fcmp ole X, -inf -> fcmp oeq X, -inf fcmp ogt X, -inf -> fcmp one X, -inf fcmp oge X, -inf -> fcmp ord X, 0 fcmp ult X, -inf -> fcmp uno X, 0 fcmp ule X, -inf -> fcmp ueq X, -inf fcmp ugt X, -inf -> fcmp une X, -inf fcmp uge X, -inf -> true ``` Alive2: https://alive2.llvm.org/ce/z/FRqqDg The motivation of this patch is to fix the regression found in dtcxzyw/llvm-opt-benchmark#199 (comment).
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‎llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp‎

Lines changed: 44 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7747,6 +7747,50 @@ Instruction *InstCombinerImpl::visitFCmpInst(FCmpInst &I) {
77477747
if (match(Op1, m_AnyZeroFP()) && !match(Op1, m_PosZeroFP()))
77487748
return replaceOperand(I, 1, ConstantFP::getZero(OpType));
77497749

7750+
// Canonicalize:
7751+
// fcmp olt X, +inf -> fcmp one X, +inf
7752+
// fcmp ole X, +inf -> fcmp ord X, 0
7753+
// fcmp ogt X, +inf -> false
7754+
// fcmp oge X, +inf -> fcmp oeq X, +inf
7755+
// fcmp ult X, +inf -> fcmp une X, +inf
7756+
// fcmp ule X, +inf -> true
7757+
// fcmp ugt X, +inf -> fcmp uno X, 0
7758+
// fcmp uge X, +inf -> fcmp ueq X, +inf
7759+
// fcmp olt X, -inf -> false
7760+
// fcmp ole X, -inf -> fcmp oeq X, -inf
7761+
// fcmp ogt X, -inf -> fcmp one X, -inf
7762+
// fcmp oge X, -inf -> fcmp ord X, 0
7763+
// fcmp ult X, -inf -> fcmp uno X, 0
7764+
// fcmp ule X, -inf -> fcmp ueq X, -inf
7765+
// fcmp ugt X, -inf -> fcmp une X, -inf
7766+
// fcmp uge X, -inf -> true
7767+
const APFloat *C;
7768+
if (match(Op1, m_APFloat(C)) && C->isInfinity()) {
7769+
switch (C->isNegative() ? FCmpInst::getSwappedPredicate(Pred) : Pred) {
7770+
case FCmpInst::FCMP_ORD:
7771+
case FCmpInst::FCMP_UNO:
7772+
case FCmpInst::FCMP_TRUE:
7773+
case FCmpInst::FCMP_FALSE:
7774+
case FCmpInst::FCMP_OGT:
7775+
case FCmpInst::FCMP_ULE:
7776+
llvm_unreachable("Should be simplified by InstSimplify");
7777+
case FCmpInst::FCMP_OLT:
7778+
return new FCmpInst(FCmpInst::FCMP_ONE, Op0, Op1, "", &I);
7779+
case FCmpInst::FCMP_OLE:
7780+
return new FCmpInst(FCmpInst::FCMP_ORD, Op0, ConstantFP::getZero(OpType),
7781+
"", &I);
7782+
case FCmpInst::FCMP_OGE:
7783+
return new FCmpInst(FCmpInst::FCMP_OEQ, Op0, Op1, "", &I);
7784+
case FCmpInst::FCMP_ULT:
7785+
return new FCmpInst(FCmpInst::FCMP_UNE, Op0, Op1, "", &I);
7786+
case FCmpInst::FCMP_UGT:
7787+
return new FCmpInst(FCmpInst::FCMP_UNO, Op0, ConstantFP::getZero(OpType),
7788+
"", &I);
7789+
case FCmpInst::FCMP_UGE:
7790+
return new FCmpInst(FCmpInst::FCMP_UEQ, Op0, Op1, "", &I);
7791+
}
7792+
}
7793+
77507794
// Ignore signbit of bitcasted int when comparing equality to FP 0.0:
77517795
// fcmp oeq/une (bitcast X), 0.0 --> (and X, SignMaskC) ==/!= 0
77527796
if (match(Op1, m_PosZeroFP()) &&
@@ -7858,7 +7902,6 @@ Instruction *InstCombinerImpl::visitFCmpInst(FCmpInst &I) {
78587902
// TODO: Simplify if the copysign constant is 0.0 or NaN.
78597903
// TODO: Handle non-zero compare constants.
78607904
// TODO: Handle other predicates.
7861-
const APFloat *C;
78627905
if (match(Op0, m_OneUse(m_Intrinsic<Intrinsic::copysign>(m_APFloat(C),
78637906
m_Value(X)))) &&
78647907
match(Op1, m_AnyZeroFP()) && !C->isZero() && !C->isNaN()) {

‎llvm/test/Transforms/InstCombine/and-fcmp.ll‎

Lines changed: 20 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -4614,7 +4614,7 @@ define i1 @intersect_fmf_4(double %a, double %b) {
46144614
define i1 @clang_builtin_isnormal_inf_check(half %x) {
46154615
; CHECK-LABEL: @clang_builtin_isnormal_inf_check(
46164616
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4617-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4617+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
46184618
; CHECK-NEXT: ret i1 [[AND]]
46194619
;
46204620
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4627,7 +4627,7 @@ define i1 @clang_builtin_isnormal_inf_check(half %x) {
46274627
define <2 x i1> @clang_builtin_isnormal_inf_check_vector(<2 x half> %x) {
46284628
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_vector(
46294629
; CHECK-NEXT: [[FABS_X:%.*]] = call <2 x half> @llvm.fabs.v2f16(<2 x half> [[X:%.*]])
4630-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge <2 x half> [[FABS_X]], <half 0xH7C00, half 0xH7C00>
4630+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq <2 x half> [[FABS_X]], <half 0xH7C00, half 0xH7C00>
46314631
; CHECK-NEXT: ret <2 x i1> [[AND]]
46324632
;
46334633
%fabs.x = call <2 x half> @llvm.fabs.v2f16(<2 x half> %x)
@@ -4640,7 +4640,7 @@ define <2 x i1> @clang_builtin_isnormal_inf_check_vector(<2 x half> %x) {
46404640
define i1 @clang_builtin_isnormal_inf_check_commute(half %x) {
46414641
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_commute(
46424642
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4643-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4643+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
46444644
; CHECK-NEXT: ret i1 [[AND]]
46454645
;
46464646
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4653,7 +4653,7 @@ define i1 @clang_builtin_isnormal_inf_check_commute(half %x) {
46534653
define i1 @clang_builtin_isnormal_inf_check_commute_nsz_rhs(half %x) {
46544654
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_commute_nsz_rhs(
46554655
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4656-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4656+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
46574657
; CHECK-NEXT: ret i1 [[AND]]
46584658
;
46594659
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4666,7 +4666,7 @@ define i1 @clang_builtin_isnormal_inf_check_commute_nsz_rhs(half %x) {
46664666
define i1 @clang_builtin_isnormal_inf_check_commute_nsz_lhs(half %x) {
46674667
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_commute_nsz_lhs(
46684668
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4669-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4669+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
46704670
; CHECK-NEXT: ret i1 [[AND]]
46714671
;
46724672
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4690,7 +4690,7 @@ define i1 @clang_builtin_isnormal_inf_check_commute_nofabs_ueq(half %x) {
46904690
define i1 @clang_builtin_isnormal_inf_check_commute_nsz(half %x) {
46914691
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_commute_nsz(
46924692
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4693-
; CHECK-NEXT: [[AND:%.*]] = fcmp nsz oge half [[FABS_X]], 0xH7C00
4693+
; CHECK-NEXT: [[AND:%.*]] = fcmp nsz oeq half [[FABS_X]], 0xH7C00
46944694
; CHECK-NEXT: ret i1 [[AND]]
46954695
;
46964696
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4716,7 +4716,7 @@ define i1 @clang_builtin_isnormal_inf_check_ugt(half %x) {
47164716
define i1 @clang_builtin_isnormal_inf_check_ult(half %x) {
47174717
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_ult(
47184718
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4719-
; CHECK-NEXT: [[AND:%.*]] = fcmp olt half [[FABS_X]], 0xH7C00
4719+
; CHECK-NEXT: [[AND:%.*]] = fcmp one half [[FABS_X]], 0xH7C00
47204720
; CHECK-NEXT: ret i1 [[AND]]
47214721
;
47224722
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4820,8 +4820,8 @@ define i1 @clang_builtin_isnormal_inf_check_olt(half %x) {
48204820

48214821
define i1 @clang_builtin_isnormal_inf_check_ole(half %x) {
48224822
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_ole(
4823-
; CHECK-NEXT: [[AND:%.*]] = fcmp ord half [[X:%.*]], 0xH0000
4824-
; CHECK-NEXT: ret i1 [[AND]]
4823+
; CHECK-NEXT: [[CMP:%.*]] = fcmp ord half [[X:%.*]], 0xH0000
4824+
; CHECK-NEXT: ret i1 [[CMP]]
48254825
;
48264826
%fabs.x = call half @llvm.fabs.f16(half %x)
48274827
%ord = fcmp ord half %fabs.x, 0.0
@@ -4846,7 +4846,7 @@ define i1 @clang_builtin_isnormal_inf_check_oeq(half %x) {
48464846
define i1 @clang_builtin_isnormal_inf_check_unnececcary_fabs(half %x) {
48474847
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_unnececcary_fabs(
48484848
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4849-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4849+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
48504850
; CHECK-NEXT: ret i1 [[AND]]
48514851
;
48524852
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4871,7 +4871,7 @@ define i1 @clang_builtin_isnormal_inf_check_not_ord(half %x) {
48714871

48724872
define i1 @clang_builtin_isnormal_inf_check_missing_fabs(half %x) {
48734873
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_missing_fabs(
4874-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[X:%.*]], 0xH7C00
4874+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[X:%.*]], 0xH7C00
48754875
; CHECK-NEXT: ret i1 [[AND]]
48764876
;
48774877
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4912,7 +4912,7 @@ define i1 @clang_builtin_isnormal_inf_check_not_inf(half %x) {
49124912
define i1 @clang_builtin_isnormal_inf_check_nsz_lhs(half %x) {
49134913
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_nsz_lhs(
49144914
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4915-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4915+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
49164916
; CHECK-NEXT: ret i1 [[AND]]
49174917
;
49184918
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4925,7 +4925,7 @@ define i1 @clang_builtin_isnormal_inf_check_nsz_lhs(half %x) {
49254925
define i1 @clang_builtin_isnormal_inf_check_nsz_rhs(half %x) {
49264926
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_nsz_rhs(
49274927
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4928-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4928+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
49294929
; CHECK-NEXT: ret i1 [[AND]]
49304930
;
49314931
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4938,7 +4938,7 @@ define i1 @clang_builtin_isnormal_inf_check_nsz_rhs(half %x) {
49384938
define i1 @clang_builtin_isnormal_inf_check_nsz(half %x) {
49394939
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_nsz(
49404940
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4941-
; CHECK-NEXT: [[AND:%.*]] = fcmp nsz oge half [[FABS_X]], 0xH7C00
4941+
; CHECK-NEXT: [[AND:%.*]] = fcmp nsz oeq half [[FABS_X]], 0xH7C00
49424942
; CHECK-NEXT: ret i1 [[AND]]
49434943
;
49444944
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4950,7 +4950,7 @@ define i1 @clang_builtin_isnormal_inf_check_nsz(half %x) {
49504950

49514951
define i1 @clang_builtin_isnormal_inf_check_fneg(half %x) {
49524952
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_fneg(
4953-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[X:%.*]], 0xH7C00
4953+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[X:%.*]], 0xH7C00
49544954
; CHECK-NEXT: ret i1 [[AND]]
49554955
;
49564956
%fneg.x = fneg half %x
@@ -4963,7 +4963,7 @@ define i1 @clang_builtin_isnormal_inf_check_fneg(half %x) {
49634963
define i1 @clang_builtin_isnormal_inf_check_copysign(half %x, half %y) {
49644964
; CHECK-LABEL: @clang_builtin_isnormal_inf_check_copysign(
49654965
; CHECK-NEXT: [[COPYSIGN_X:%.*]] = call half @llvm.copysign.f16(half [[X:%.*]], half [[Y:%.*]])
4966-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[COPYSIGN_X]], 0xH7C00
4966+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[COPYSIGN_X]], 0xH7C00
49674967
; CHECK-NEXT: ret i1 [[AND]]
49684968
;
49694969
%copysign.x = call half @llvm.copysign.f16(half %x, half %y)
@@ -4976,7 +4976,7 @@ define i1 @clang_builtin_isnormal_inf_check_copysign(half %x, half %y) {
49764976
define i1 @isnormal_logical_select_0(half %x) {
49774977
; CHECK-LABEL: @isnormal_logical_select_0(
49784978
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4979-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4979+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
49804980
; CHECK-NEXT: ret i1 [[AND]]
49814981
;
49824982
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -4989,7 +4989,7 @@ define i1 @isnormal_logical_select_0(half %x) {
49894989
define i1 @isnormal_logical_select_1(half %x) {
49904990
; CHECK-LABEL: @isnormal_logical_select_1(
49914991
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
4992-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
4992+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
49934993
; CHECK-NEXT: ret i1 [[AND]]
49944994
;
49954995
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -5002,7 +5002,7 @@ define i1 @isnormal_logical_select_1(half %x) {
50025002
define i1 @isnormal_logical_select_0_fmf0(half %x) {
50035003
; CHECK-LABEL: @isnormal_logical_select_0_fmf0(
50045004
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
5005-
; CHECK-NEXT: [[AND:%.*]] = fcmp reassoc nsz arcp oge half [[FABS_X]], 0xH7C00
5005+
; CHECK-NEXT: [[AND:%.*]] = fcmp reassoc nsz arcp oeq half [[FABS_X]], 0xH7C00
50065006
; CHECK-NEXT: ret i1 [[AND]]
50075007
;
50085008
%fabs.x = call half @llvm.fabs.f16(half %x)
@@ -5015,7 +5015,7 @@ define i1 @isnormal_logical_select_0_fmf0(half %x) {
50155015
define i1 @isnormal_logical_select_0_fmf1(half %x) {
50165016
; CHECK-LABEL: @isnormal_logical_select_0_fmf1(
50175017
; CHECK-NEXT: [[FABS_X:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
5018-
; CHECK-NEXT: [[AND:%.*]] = fcmp oge half [[FABS_X]], 0xH7C00
5018+
; CHECK-NEXT: [[AND:%.*]] = fcmp oeq half [[FABS_X]], 0xH7C00
50195019
; CHECK-NEXT: ret i1 [[AND]]
50205020
;
50215021
%fabs.x = call half @llvm.fabs.f16(half %x)

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