Allow constant folding of round function whenever feasible

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203198 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Karthik Bhat 2014-03-07 04:36:21 +00:00
parent 40e107d960
commit 70957b9c55
2 changed files with 97 additions and 0 deletions

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@ -1196,6 +1196,7 @@ bool llvm::canConstantFoldCallTo(const Function *F) {
case Intrinsic::fma:
case Intrinsic::fmuladd:
case Intrinsic::copysign:
case Intrinsic::round:
case Intrinsic::sadd_with_overflow:
case Intrinsic::uadd_with_overflow:
case Intrinsic::ssub_with_overflow:
@ -1345,6 +1346,12 @@ static Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID,
if (!Ty->isHalfTy() && !Ty->isFloatTy() && !Ty->isDoubleTy())
return 0;
if (IntrinsicID == Intrinsic::round) {
APFloat V = Op->getValueAPF();
V.roundToIntegral(APFloat::rmNearestTiesToAway);
return ConstantFP::get(Ty->getContext(), V);
}
/// We only fold functions with finite arguments. Folding NaN and inf is
/// likely to be aborted with an exception anyway, and some host libms
/// have known errors raising exceptions.

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@ -0,0 +1,90 @@
; RUN: opt -S -instcombine < %s | FileCheck %s
declare float @llvm.round.f32(float) #0
declare double @llvm.round.f64(double) #0
; CHECK-LABEL: @constant_fold_round_f32_01
; CHECK-NEXT: ret float 1.000000e+00
define float @constant_fold_round_f32_01() #0 {
%x = call float @llvm.round.f32(float 1.25) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f32_02
; CHECK-NEXT: ret float -1.000000e+00
define float @constant_fold_round_f32_02() #0 {
%x = call float @llvm.round.f32(float -1.25) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f32_03
; CHECK-NEXT: ret float 2.000000e+00
define float @constant_fold_round_f32_03() #0 {
%x = call float @llvm.round.f32(float 1.5) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f32_04
; CHECK-NEXT: ret float -2.000000e+00
define float @constant_fold_round_f32_04() #0 {
%x = call float @llvm.round.f32(float -1.5) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f32_05
; CHECK-NEXT: ret float 3.000000e+00
define float @constant_fold_round_f32_05() #0 {
%x = call float @llvm.round.f32(float 2.75) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f32_06
; CHECK-NEXT: ret float -3.000000e+00
define float @constant_fold_round_f32_06() #0 {
%x = call float @llvm.round.f32(float -2.75) #0
ret float %x
}
; CHECK-LABEL: @constant_fold_round_f64_01
; CHECK-NEXT: ret double 1.000000e+00
define double @constant_fold_round_f64_01() #0 {
%x = call double @llvm.round.f64(double 1.3) #0
ret double %x
}
; CHECK-LABEL: @constant_fold_round_f64_02
; CHECK-NEXT: ret double -1.000000e+00
define double @constant_fold_round_f64_02() #0 {
%x = call double @llvm.round.f64(double -1.3) #0
ret double %x
}
; CHECK-LABEL: @constant_fold_round_f64_03
; CHECK-NEXT: ret double 2.000000e+00
define double @constant_fold_round_f64_03() #0 {
%x = call double @llvm.round.f64(double 1.5) #0
ret double %x
}
; CHECK-LABEL: @constant_fold_round_f64_04
; CHECK-NEXT: ret double -2.000000e+00
define double @constant_fold_round_f64_04() #0 {
%x = call double @llvm.round.f64(double -1.5) #0
ret double %x
}
; CHECK-LABEL: @constant_fold_round_f64_05
; CHECK-NEXT: ret double 3.000000e+00
define double @constant_fold_round_f64_05() #0 {
%x = call double @llvm.round.f64(double 2.7) #0
ret double %x
}
; CHECK-LABEL: @constant_fold_round_f64_06
; CHECK-NEXT: ret double -3.000000e+00
define double @constant_fold_round_f64_06() #0 {
%x = call double @llvm.round.f64(double -2.7) #0
ret double %x
}
attributes #0 = { nounwind readnone }