[InstCombine] Fold fabs over select

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -3432,6 +3432,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
   case Intrinsic::uadd_sat:
   case Intrinsic::ssub_sat:
   case Intrinsic::sadd_sat:
+  case Intrinsic::fabs:
     for (Value *Op : II->args())
       if (auto *Sel = dyn_cast<SelectInst>(Op))
         if (Instruction *R = FoldOpIntoSelect(*II, Sel))

llvm/test/Transforms/InstCombine/fabs.ll

@@ -179,9 +179,9 @@ define float @fabs_select_constant_neg0(i32 %c) {
 define float @fabs_select_var_constant_negative(i32 %c, float %x) {
 ; CHECK-LABEL: @fabs_select_var_constant_negative(
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[C:%.*]], 0
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[CMP]], float [[X:%.*]], float -1.000000e+00
-; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
-; CHECK-NEXT:    ret float [[FABS]]
+; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT:%.*]])
+; CHECK-NEXT:    [[FABS1:%.*]] = select i1 [[CMP]], float [[FABS]], float 1.000000e+00
+; CHECK-NEXT:    ret float [[FABS1]]
 ;
   %cmp = icmp eq i32 %c, 0
   %select = select i1 %cmp, float %x, float -1.0

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

@@ -285,9 +285,7 @@ define double @test_fabs_select1(double %a) {
 ; CHECK-LABEL: @test_fabs_select1(
 ; CHECK-NEXT:    [[COND:%.*]] = fcmp uno double [[A:%.*]], 0.000000e+00
 ; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND]], double 0x7FF8000000000000, double [[A]]
-; CHECK-NEXT:    [[FABS:%.*]] = call double @llvm.fabs.f64(double [[SEL1]])
-; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND]], double [[FABS]], double [[A]]
-; CHECK-NEXT:    ret double [[SEL2]]
+; CHECK-NEXT:    ret double [[SEL1]]
 ;
   %cond = fcmp uno double %a, 0.000000e+00
   %sel1 = select i1 %cond, double 0x7FF8000000000000, double %a
@@ -300,8 +298,7 @@ define double @test_fabs_select2(double %a) {
 ; CHECK-LABEL: @test_fabs_select2(
 ; CHECK-NEXT:    [[ABS1:%.*]] = call double @llvm.fabs.f64(double [[A:%.*]])
 ; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq double [[ABS1]], 0x7FF0000000000000
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], double -0.000000e+00, double [[ABS1]]
-; CHECK-NEXT:    [[ABS2:%.*]] = call double @llvm.fabs.f64(double [[SEL]])
+; CHECK-NEXT:    [[ABS2:%.*]] = select i1 [[CMP]], double 0.000000e+00, double [[ABS1]]
 ; CHECK-NEXT:    ret double [[ABS2]]
 ;
   %abs1 = call double @llvm.fabs.f64(double %a)

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

@@ -387,8 +387,8 @@ define nofpclass(inf) float @ret_nofpclass_inf__fabs_select_pinf_rhs(i1 %cond, f
 define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__fabs_select_pinf_rhs(i1 %cond, float %x) {
 ; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives__fabs_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[FABS:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[FABS]]
 ;
   %select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -411,8 +411,8 @@ define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__fabs_
 define nofpclass(nan ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives_nan__fabs_select_pinf_rhs(i1 %cond, float %x) {
 ; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives_nan__fabs_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[FABS:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[FABS]]
 ;
   %select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -665,8 +665,8 @@ define nofpclass(inf pnorm psub pzero) float @ret_nofpclass_no_positives_noinf__
 define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
 ; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives__copysign_unknown_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[COPYSIGN:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[COPYSIGN:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[COPYSIGN]]
 ;
   %select = select i1 %cond, float %x, float 0x7FF0000000000000
@@ -678,8 +678,8 @@ define nofpclass(ninf nnorm nsub nzero) float @ret_nofpclass_no_negatives__copys
 define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__copysign_unknown_select_pinf_rhs(i1 %cond, float %x, float %unknown.sign) {
 ; CHECK-LABEL: define nofpclass(pinf pzero psub pnorm) float @ret_nofpclass_no_positives__copysign_unknown_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP2:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[COND]], float [[TMP2]], float 0x7FF0000000000000
 ; CHECK-NEXT:    [[COPYSIGN:%.*]] = fneg float [[TMP1]]
 ; CHECK-NEXT:    ret float [[COPYSIGN]]
 ;
@@ -692,8 +692,8 @@ define nofpclass(pinf pnorm psub pzero) float @ret_nofpclass_no_positives__copys
 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) {
 ; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) float @ret_nofpclass_no_negatives_nonan__copysign_unknown_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[COPYSIGN:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[COPYSIGN:%.*]] = select i1 [[COND]], float [[TMP1]], float 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[COPYSIGN]]
 ;
   %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
 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) {
 ; CHECK-LABEL: define nofpclass(nan pinf pzero psub pnorm) float @ret_nofpclass_no_positives_nonan__copysign_unknown_select_pinf_rhs
 ; CHECK-SAME: (i1 [[COND:%.*]], float [[X:%.*]], float [[UNKNOWN_SIGN:%.*]]) {
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0x7FF0000000000000
-; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.fabs.f32(float [[SELECT]])
+; CHECK-NEXT:    [[TMP2:%.*]] = call float @llvm.fabs.f32(float [[X]])
+; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[COND]], float [[TMP2]], float 0x7FF0000000000000
 ; CHECK-NEXT:    [[COPYSIGN:%.*]] = fneg float [[TMP1]]
 ; CHECK-NEXT:    ret float [[COPYSIGN]]
 ;