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[InstCombine] Fold fabs over select
1 parent aef2236 commit f6d142a

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4 files changed

+31
-30
lines changed

4 files changed

+31
-30
lines changed

‎llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

Lines changed: 8 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2497,10 +2497,16 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
24972497
if (match(II->getArgOperand(0),
24982498
m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))) {
24992499
// fabs (select Cond, TrueC, FalseC) --> select Cond, AbsT, AbsF
2500-
if (isa<Constant>(TVal) && isa<Constant>(FVal)) {
2500+
if (isa<Constant>(TVal) || isa<Constant>(FVal)) {
25012501
CallInst *AbsT = Builder.CreateCall(II->getCalledFunction(), {TVal});
25022502
CallInst *AbsF = Builder.CreateCall(II->getCalledFunction(), {FVal});
2503-
return SelectInst::Create(Cond, AbsT, AbsF);
2503+
SelectInst *SI = SelectInst::Create(Cond, AbsT, AbsF);
2504+
FastMathFlags FMF1 = II->getFastMathFlags();
2505+
FastMathFlags FMF2 =
2506+
cast<SelectInst>(II->getArgOperand(0))->getFastMathFlags();
2507+
FMF2.setNoSignedZeros(false);
2508+
SI->setFastMathFlags(FMF1 | FMF2);
2509+
return SI;
25042510
}
25052511
// fabs (select Cond, -FVal, FVal) --> fabs FVal
25062512
if (match(TVal, m_FNeg(m_Specific(FVal))))

‎llvm/test/Transforms/InstCombine/fabs.ll

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -179,9 +179,9 @@ define float @fabs_select_constant_neg0(i32 %c) {
179179
define float @fabs_select_var_constant_negative(i32 %c, float %x) {
180180
; CHECK-LABEL: @fabs_select_var_constant_negative(
181181
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[C:%.*]], 0
182-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP]], float [[X:%.*]], float -1.000000e+00
183-
; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
184-
; CHECK-NEXT: ret float [[FABS]]
182+
; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT:%.*]])
183+
; CHECK-NEXT: [[FABS1:%.*]] = select i1 [[CMP]], float [[FABS]], float 1.000000e+00
184+
; CHECK-NEXT: ret float [[FABS1]]
185185
;
186186
%cmp = icmp eq i32 %c, 0
187187
%select = select i1 %cmp, float %x, float -1.0

‎llvm/test/Transforms/InstCombine/intrinsic-select.ll

Lines changed: 8 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -285,9 +285,7 @@ define double @test_fabs_select1(double %a) {
285285
; CHECK-LABEL: @test_fabs_select1(
286286
; CHECK-NEXT: [[COND:%.*]] = fcmp uno double [[A:%.*]], 0.000000e+00
287287
; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[COND]], double 0x7FF8000000000000, double [[A]]
288-
; CHECK-NEXT: [[FABS:%.*]] = call double @llvm.fabs.f64(double [[SEL1]])
289-
; CHECK-NEXT: [[SEL2:%.*]] = select i1 [[COND]], double [[FABS]], double [[A]]
290-
; CHECK-NEXT: ret double [[SEL2]]
288+
; CHECK-NEXT: ret double [[SEL1]]
291289
;
292290
%cond = fcmp uno double %a, 0.000000e+00
293291
%sel1 = select i1 %cond, double 0x7FF8000000000000, double %a
@@ -300,9 +298,7 @@ define <2 x double> @test_fabs_select1_vec(<2 x double> %a) {
300298
; CHECK-LABEL: @test_fabs_select1_vec(
301299
; CHECK-NEXT: [[COND:%.*]] = fcmp uno <2 x double> [[A:%.*]], zeroinitializer
302300
; CHECK-NEXT: [[SEL2:%.*]] = select <2 x i1> [[COND]], <2 x double> <double 0x7FF8000000000000, double 0x7FF8000000000000>, <2 x double> [[A]]
303-
; CHECK-NEXT: [[FABS:%.*]] = call <2 x double> @llvm.fabs.v2f64(<2 x double> [[SEL2]])
304-
; CHECK-NEXT: [[SEL3:%.*]] = select <2 x i1> [[COND]], <2 x double> [[FABS]], <2 x double> [[A]]
305-
; CHECK-NEXT: ret <2 x double> [[SEL3]]
301+
; CHECK-NEXT: ret <2 x double> [[SEL2]]
306302
;
307303
%cond = fcmp uno <2 x double> %a, zeroinitializer
308304
%sel1 = select <2 x i1> %cond, <2 x double> splat(double 0x7FF8000000000000), <2 x double> %a
@@ -315,8 +311,7 @@ define double @test_fabs_select2(double %a) {
315311
; CHECK-LABEL: @test_fabs_select2(
316312
; CHECK-NEXT: [[ABS1:%.*]] = call double @llvm.fabs.f64(double [[A:%.*]])
317313
; CHECK-NEXT: [[CMP:%.*]] = fcmp oeq double [[ABS1]], 0x7FF0000000000000
318-
; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], double -0.000000e+00, double [[ABS1]]
319-
; CHECK-NEXT: [[ABS2:%.*]] = call double @llvm.fabs.f64(double [[SEL]])
314+
; CHECK-NEXT: [[ABS2:%.*]] = select i1 [[CMP]], double 0.000000e+00, double [[ABS1]]
320315
; CHECK-NEXT: ret double [[ABS2]]
321316
;
322317
%abs1 = call double @llvm.fabs.f64(double %a)
@@ -330,9 +325,9 @@ define double @test_fabs_select2(double %a) {
330325

331326
define double @test_fabs_select_fmf1(i1 %cond, double %a) {
332327
; CHECK-LABEL: @test_fabs_select_fmf1(
333-
; CHECK-NEXT: [[A1:%.*]] = select nnan ninf nsz i1 [[COND:%.*]], double 0.000000e+00, double [[A2:%.*]]
334-
; CHECK-NEXT: [[A:%.*]] = call double @llvm.fabs.f64(double [[A1]])
335-
; CHECK-NEXT: ret double [[A]]
328+
; CHECK-NEXT: [[A:%.*]] = call double @llvm.fabs.f64(double [[A1:%.*]])
329+
; CHECK-NEXT: [[FABS:%.*]] = select nnan ninf i1 [[COND:%.*]], double 0.000000e+00, double [[A]]
330+
; CHECK-NEXT: ret double [[FABS]]
336331
;
337332
%sel1 = select nnan ninf nsz i1 %cond, double 0.0, double %a
338333
%fabs = call double @llvm.fabs.f64(double %sel1)
@@ -341,8 +336,8 @@ define double @test_fabs_select_fmf1(i1 %cond, double %a) {
341336

342337
define double @test_fabs_select_fmf2(i1 %cond, double %a) {
343338
; CHECK-LABEL: @test_fabs_select_fmf2(
344-
; CHECK-NEXT: [[SEL2:%.*]] = select i1 [[COND:%.*]], double 0.000000e+00, double [[A:%.*]]
345-
; CHECK-NEXT: [[SEL1:%.*]] = call nnan ninf nsz double @llvm.fabs.f64(double [[SEL2]])
339+
; CHECK-NEXT: [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[A:%.*]])
340+
; CHECK-NEXT: [[SEL1:%.*]] = select nnan ninf nsz i1 [[COND:%.*]], double 0.000000e+00, double [[TMP1]]
346341
; CHECK-NEXT: ret double [[SEL1]]
347342
;
348343
%sel1 = select i1 %cond, double 0.0, double %a

‎llvm/test/Transforms/InstCombine/simplify-demanded-fpclass.ll

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -387,8 +387,8 @@ define nofpclass(inf) float @ret_nofpclass_inf__fabs_select_pinf_rhs(i1 %cond, f
387387
define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__fabs_select_pinf_rhs(i1 %cond, float %x) {
388388
; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives__fabs_select_pinf_rhs
389389
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]]) {
390-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
391-
; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
390+
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
391+
; CHECK-NEXT: [[FABS:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
392392
; CHECK-NEXT: ret float [[FABS]]
393393
;
394394
%select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -411,8 +411,8 @@ define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__fabs_
411411
define nofpclass(nan ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives_nan__fabs_select_pinf_rhs(i1 %cond, float %x) {
412412
; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives_nan__fabs_select_pinf_rhs
413413
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]]) {
414-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
415-
; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
414+
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
415+
; CHECK-NEXT: [[FABS:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
416416
; CHECK-NEXT: ret float [[FABS]]
417417
;
418418
%select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -665,8 +665,8 @@ define nofpclass(inf pnorm psub pzero) float @ret_nofpclass_no_positives_noinf__
665665
define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
666666
; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives__copysign_unknown_select_pinf_rhs
667667
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
668-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
669-
; CHECK-NEXT: [[COPYSIGN:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
668+
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
669+
; CHECK-NEXT: [[COPYSIGN:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
670670
; CHECK-NEXT: ret float [[COPYSIGN]]
671671
;
672672
%select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -678,8 +678,8 @@ define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__copys
678678
define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
679679
; CHECK-LABEL: define nofpclass(pinf pzero psub pnorm) float @ret_nofpclass_no_positives__copysign_unknown_select_pinf_rhs
680680
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
681-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
682-
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
681+
; CHECK-NEXT: [[TMP2:%.*]] = call float @llvm.fabs.f32(float [[X]])
682+
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[COND]], float [[TMP2]], float 0x7FF0000000000000
683683
; CHECK-NEXT: [[COPYSIGN:%.*]] = fneg float [[TMP1]]
684684
; CHECK-NEXT: ret float [[COPYSIGN]]
685685
;
@@ -692,8 +692,8 @@ define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__copys
692692
define nofpclass(nan ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives_nonan__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
693693
; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives_nonan__copysign_unknown_select_pinf_rhs
694694
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
695-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
696-
; CHECK-NEXT: [[COPYSIGN:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
695+
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
696+
; CHECK-NEXT: [[COPYSIGN:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
697697
; CHECK-NEXT: ret float [[COPYSIGN]]
698698
;
699699
%select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -705,8 +705,8 @@ define nofpclass(nan ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives_no
705705
define nofpclass(nan pinf pnorm psub pzero) float @ret_nofpclass_no_positives_nonan__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
706706
; CHECK-LABEL: define nofpclass(nan pinf pzero psub pnorm) float @ret_nofpclass_no_positives_nonan__copysign_unknown_select_pinf_rhs
707707
; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
708-
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
709-
; CHECK-NEXT: [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
708+
; CHECK-NEXT: [[TMP2:%.*]] = call float @llvm.fabs.f32(float [[X]])
709+
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[COND]], float [[TMP2]], float 0x7FF0000000000000
710710
; CHECK-NEXT: [[COPYSIGN:%.*]] = fneg float [[TMP1]]
711711
; CHECK-NEXT: ret float [[COPYSIGN]]
712712
;

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