[InstCombine] Improve select equiv fold for float type

Author: vfdff

llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp

@@ -517,11 +517,11 @@ static bool simplifySeqSelectWithSameCond(SelectInst &SI,
     Type *SelType = SINext->getType();
     Value *ValOp = SINext->getOperand(OpIndex);
     Value *CondNext;
-    // Only support the type of select is an integer type as float type need
-    // address FMF flag.
+    // Don't need propagate FMF flag because we update the operand of SINext
+    // directly.
+    // It is not profitable to build a new select for SINext with multi-arms.
     while (match(ValOp, m_Select(m_Value(CondNext), m_Value(), m_Value()))) {
-      if (CondNext == CondVal && SelType->isIntOrIntVectorTy() &&
-          SINext->hasOneUse()) {
+      if (CondNext == CondVal && SINext->hasOneUse()) {
         IC.replaceOperand(*SINext, OpIndex,
                           cast<SelectInst>(ValOp)->getOperand(OpIndex));
         return true;

llvm/test/Transforms/InstCombine/select.ll

@@ -4551,9 +4551,8 @@ define i32 @sequence_select_with_same_cond_true(i1 %c1, i1 %c2){
 
 define double @sequence_select_with_same_cond_double(double %a, i1 %c1, i1 %c2, double %r1, double %r2){
 ; CHECK-LABEL: @sequence_select_with_same_cond_double(
-; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], double 1.000000e+00, double 0.000000e+00
-; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], double [[S1]], double 2.000000e+00
-; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1]], double [[S2]], double 3.000000e+00
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], double 1.000000e+00, double 2.000000e+00
+; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1:%.*]], double [[S2]], double 3.000000e+00
 ; CHECK-NEXT:    ret double [[S3]]
 ;
   %s1 = select i1 %c1, double 1.0, double 0.0
@@ -4565,9 +4564,8 @@ define double @sequence_select_with_same_cond_double(double %a, i1 %c1, i1 %c2,
 ; Confirm the FMF flag is propagated
 define float @sequence_select_with_same_cond_float_and_fmf_flag1(i1 %c1, i1 %c2){
 ; CHECK-LABEL: @sequence_select_with_same_cond_float_and_fmf_flag1(
-; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], float 2.300000e+01, float 4.500000e+01
-; CHECK-NEXT:    [[S2:%.*]] = select fast i1 [[C2:%.*]], float 6.660000e+02, float [[S1]]
-; CHECK-NEXT:    [[S3:%.*]] = select fast i1 [[C1]], float 7.890000e+02, float [[S2]]
+; CHECK-NEXT:    [[S2:%.*]] = select fast i1 [[C2:%.*]], float 6.660000e+02, float 4.500000e+01
+; CHECK-NEXT:    [[S3:%.*]] = select fast i1 [[C1:%.*]], float 7.890000e+02, float [[S2]]
 ; CHECK-NEXT:    ret float [[S3]]
 ;
   %s1 = select i1 %c1, float 23.0, float 45.0
@@ -4578,9 +4576,8 @@ define float @sequence_select_with_same_cond_float_and_fmf_flag1(i1 %c1, i1 %c2)
 
 define float @sequence_select_with_same_cond_float_and_fmf_flag2(i1 %c1, i1 %c2){
 ; CHECK-LABEL: @sequence_select_with_same_cond_float_and_fmf_flag2(
-; CHECK-NEXT:    [[S1:%.*]] = select fast i1 [[C1:%.*]], float 2.300000e+01, float 4.500000e+01
-; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], float 6.660000e+02, float [[S1]]
-; CHECK-NEXT:    [[S3:%.*]] = select fast i1 [[C1]], float 7.890000e+02, float [[S2]]
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], float 6.660000e+02, float 4.500000e+01
+; CHECK-NEXT:    [[S3:%.*]] = select fast i1 [[C1:%.*]], float 7.890000e+02, float [[S2]]
 ; CHECK-NEXT:    ret float [[S3]]
 ;
   %s1 = select fast i1 %c1, float 23.0, float 45.0