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SimplifyLibCalls: Emit vector ldexp intrinsics in exp2->ldexp combine (…
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…#92219)

Co-authored-by: Nikita Popov <github@npopov.com>
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@arsenm @nikic
arsenm and nikic committed May 16, 2024
1 parent cd5ee27 commit 0ea178b
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Showing 4 changed files with 37 additions and 29 deletions.
17 changes: 9 additions & 8 deletions llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1992,11 +1992,12 @@ static Value *getIntToFPVal(Value *I2F, IRBuilderBase &B, unsigned DstWidth) {
Value *Op = cast<Instruction>(I2F)->getOperand(0);
// Make sure that the exponent fits inside an "int" of size DstWidth,
// thus avoiding any range issues that FP has not.
unsigned BitWidth = Op->getType()->getPrimitiveSizeInBits();
if (BitWidth < DstWidth ||
(BitWidth == DstWidth && isa<SIToFPInst>(I2F)))
return isa<SIToFPInst>(I2F) ? B.CreateSExt(Op, B.getIntNTy(DstWidth))
: B.CreateZExt(Op, B.getIntNTy(DstWidth));
unsigned BitWidth = Op->getType()->getScalarSizeInBits();
if (BitWidth < DstWidth || (BitWidth == DstWidth && isa<SIToFPInst>(I2F))) {
Type *IntTy = Op->getType()->getWithNewBitWidth(DstWidth);
return isa<SIToFPInst>(I2F) ? B.CreateSExt(Op, IntTy)
: B.CreateZExt(Op, IntTy);
}
}

return nullptr;
Expand Down Expand Up @@ -2366,10 +2367,10 @@ Value *LibCallSimplifier::optimizeExp2(CallInst *CI, IRBuilderBase &B) {
hasFloatVersion(M, Name))
Ret = optimizeUnaryDoubleFP(CI, B, TLI, true);

const bool UseIntrinsic = CI->doesNotAccessMemory();
// Bail out for vectors because the code below only expects scalars.
// TODO: This could be allowed if we had a ldexp intrinsic (D14327).
Type *Ty = CI->getType();
if (Ty->isVectorTy())
if (!UseIntrinsic && Ty->isVectorTy())
return Ret;

// exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= IntSize
Expand All @@ -2382,7 +2383,7 @@ Value *LibCallSimplifier::optimizeExp2(CallInst *CI, IRBuilderBase &B) {

// TODO: Emitting the intrinsic should not depend on whether the libcall
// is available.
if (CI->doesNotAccessMemory()) {
if (UseIntrinsic) {
return copyFlags(*CI, B.CreateIntrinsic(Intrinsic::ldexp,
{Ty, Exp->getType()},
{One, Exp}, CI));
Expand Down
13 changes: 4 additions & 9 deletions llvm/test/Transforms/InstCombine/exp2-1.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -308,20 +308,15 @@ define float @sitofp_scalar_intrinsic_with_FMF(i8 %x) {

define <2 x float> @sitofp_vector_intrinsic_with_FMF(<2 x i8> %x) {
; LDEXP32-LABEL: @sitofp_vector_intrinsic_with_FMF(
; LDEXP32-NEXT: [[S:%.*]] = sitofp <2 x i8> [[X:%.*]] to <2 x float>
; LDEXP32-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.exp2.v2f32(<2 x float> [[S]])
; LDEXP32-NEXT: [[TMP1:%.*]] = sext <2 x i8> [[X:%.*]] to <2 x i32>
; LDEXP32-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.ldexp.v2f32.v2i32(<2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x i32> [[TMP1]])
; LDEXP32-NEXT: ret <2 x float> [[R]]
;
; LDEXP16-LABEL: @sitofp_vector_intrinsic_with_FMF(
; LDEXP16-NEXT: [[S:%.*]] = sitofp <2 x i8> [[X:%.*]] to <2 x float>
; LDEXP16-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.exp2.v2f32(<2 x float> [[S]])
; LDEXP16-NEXT: [[TMP1:%.*]] = sext <2 x i8> [[X:%.*]] to <2 x i16>
; LDEXP16-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.ldexp.v2f32.v2i16(<2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x i16> [[TMP1]])
; LDEXP16-NEXT: ret <2 x float> [[R]]
;
; NOLDEXPF-LABEL: @sitofp_vector_intrinsic_with_FMF(
; NOLDEXPF-NEXT: [[S:%.*]] = sitofp <2 x i8> [[X:%.*]] to <2 x float>
; NOLDEXPF-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.exp2.v2f32(<2 x float> [[S]])
; NOLDEXPF-NEXT: ret <2 x float> [[R]]
;
; NOLDEXP-LABEL: @sitofp_vector_intrinsic_with_FMF(
; NOLDEXP-NEXT: [[S:%.*]] = sitofp <2 x i8> [[X:%.*]] to <2 x float>
; NOLDEXP-NEXT: [[R:%.*]] = call nnan <2 x float> @llvm.exp2.v2f32(<2 x float> [[S]])
Expand Down
32 changes: 22 additions & 10 deletions llvm/test/Transforms/InstCombine/exp2-to-ldexp.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -39,11 +39,17 @@ define float @exp2_f32_sitofp_i8_flags(i8 %x) {
}

define <2 x float> @exp2_v2f32_sitofp_v2i8(<2 x i8> %x) {
; CHECK-LABEL: define <2 x float> @exp2_v2f32_sitofp_v2i8(
; CHECK-SAME: <2 x i8> [[X:%.*]]) {
; CHECK-NEXT: [[ITOFP:%.*]] = sitofp <2 x i8> [[X]] to <2 x float>
; CHECK-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.exp2.v2f32(<2 x float> [[ITOFP]])
; CHECK-NEXT: ret <2 x float> [[EXP2]]
; LDEXP-LABEL: define <2 x float> @exp2_v2f32_sitofp_v2i8(
; LDEXP-SAME: <2 x i8> [[X:%.*]]) {
; LDEXP-NEXT: [[TMP1:%.*]] = sext <2 x i8> [[X]] to <2 x i32>
; LDEXP-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.ldexp.v2f32.v2i32(<2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x i32> [[TMP1]])
; LDEXP-NEXT: ret <2 x float> [[EXP2]]
;
; NOLDEXP-LABEL: define <2 x float> @exp2_v2f32_sitofp_v2i8(
; NOLDEXP-SAME: <2 x i8> [[X:%.*]]) {
; NOLDEXP-NEXT: [[ITOFP:%.*]] = sitofp <2 x i8> [[X]] to <2 x float>
; NOLDEXP-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.exp2.v2f32(<2 x float> [[ITOFP]])
; NOLDEXP-NEXT: ret <2 x float> [[EXP2]]
;
%itofp = sitofp <2 x i8> %x to <2 x float>
%exp2 = call <2 x float> @llvm.exp2.v2f32(<2 x float> %itofp)
Expand Down Expand Up @@ -117,11 +123,17 @@ define fp128 @exp2_fp128_sitofp_i8(i8 %x) {
}

define <vscale x 4 x float> @exp2_nxv4f32_sitofp_i8(<vscale x 4 x i8> %x) {
; CHECK-LABEL: define <vscale x 4 x float> @exp2_nxv4f32_sitofp_i8(
; CHECK-SAME: <vscale x 4 x i8> [[X:%.*]]) {
; CHECK-NEXT: [[ITOFP:%.*]] = sitofp <vscale x 4 x i8> [[X]] to <vscale x 4 x float>
; CHECK-NEXT: [[EXP2:%.*]] = call <vscale x 4 x float> @llvm.exp2.nxv4f32(<vscale x 4 x float> [[ITOFP]])
; CHECK-NEXT: ret <vscale x 4 x float> [[EXP2]]
; LDEXP-LABEL: define <vscale x 4 x float> @exp2_nxv4f32_sitofp_i8(
; LDEXP-SAME: <vscale x 4 x i8> [[X:%.*]]) {
; LDEXP-NEXT: [[TMP1:%.*]] = sext <vscale x 4 x i8> [[X]] to <vscale x 4 x i32>
; LDEXP-NEXT: [[EXP2:%.*]] = call <vscale x 4 x float> @llvm.ldexp.nxv4f32.nxv4i32(<vscale x 4 x float> shufflevector (<vscale x 4 x float> insertelement (<vscale x 4 x float> poison, float 1.000000e+00, i64 0), <vscale x 4 x float> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32> [[TMP1]])
; LDEXP-NEXT: ret <vscale x 4 x float> [[EXP2]]
;
; NOLDEXP-LABEL: define <vscale x 4 x float> @exp2_nxv4f32_sitofp_i8(
; NOLDEXP-SAME: <vscale x 4 x i8> [[X:%.*]]) {
; NOLDEXP-NEXT: [[ITOFP:%.*]] = sitofp <vscale x 4 x i8> [[X]] to <vscale x 4 x float>
; NOLDEXP-NEXT: [[EXP2:%.*]] = call <vscale x 4 x float> @llvm.exp2.nxv4f32(<vscale x 4 x float> [[ITOFP]])
; NOLDEXP-NEXT: ret <vscale x 4 x float> [[EXP2]]
;
%itofp = sitofp <vscale x 4 x i8> %x to <vscale x 4 x float>
%exp2 = call <vscale x 4 x float> @llvm.exp2.nxv4f32(<vscale x 4 x float> %itofp)
Expand Down
4 changes: 2 additions & 2 deletions llvm/test/Transforms/InstCombine/pow_fp_int.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -530,8 +530,8 @@ define double @powf_exp_const2_int_no_fast(double %base) {
define <2 x float> @pow_sitofp_const_base_2_no_fast_vector(<2 x i8> %x) {
; CHECK-LABEL: define <2 x float> @pow_sitofp_const_base_2_no_fast_vector(
; CHECK-SAME: <2 x i8> [[X:%.*]]) {
; CHECK-NEXT: [[S:%.*]] = sitofp <2 x i8> [[X]] to <2 x float>
; CHECK-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.exp2.v2f32(<2 x float> [[S]])
; CHECK-NEXT: [[TMP1:%.*]] = sext <2 x i8> [[X]] to <2 x i32>
; CHECK-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.ldexp.v2f32.v2i32(<2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x i32> [[TMP1]])
; CHECK-NEXT: ret <2 x float> [[EXP2]]
;
%s = sitofp <2 x i8> %x to <2 x float>
Expand Down

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