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[InstCombine] allow SimplifyDemandedVectorElts to work with FP binops

We're a long way from D50992 and D51553, but this is where we have to start.
We weren't back-propagating undefs into binop constant values for anything but
add/sub/mul/and/or/xor. 

This is likely because we have to be careful about not introducing UB/poison 
with div/rem/shift. But I suspect we already are getting the poison part wrong 
for add/sub/mul (although it may not be possible to expose the bug currently
because we use SimplifyDemandedVectorElts from a limited set of opcodes).
See the discussion/implementation from D48987 and D49047.

This patch just enables functionality for FP ops because those do not have 
UB/poison potential.

llvm-svn: 343727
This commit is contained in:
Sanjay Patel 2018-10-03 21:44:59 +00:00
parent 20666b0230
commit 5a76bb2cd1
5 changed files with 36 additions and 34 deletions

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@ -1378,24 +1378,6 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
}
break;
}
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
// div/rem demand all inputs, because they don't want divide by zero.
TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, UndefElts,
Depth + 1);
if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
TmpV = SimplifyDemandedVectorElts(I->getOperand(1), DemandedElts,
UndefElts2, Depth + 1);
if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; }
// Output elements are undefined if both are undefined. Consider things
// like undef&0. The result is known zero, not undef.
UndefElts &= UndefElts2;
break;
case Instruction::FPTrunc:
case Instruction::FPExt:
TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, UndefElts,
@ -1647,5 +1629,25 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
break;
}
}
// TODO: We bail completely on integer div/rem and shifts because they have
// UB/poison potential, but that should be refined.
BinaryOperator *BO;
if (match(I, m_BinOp(BO)) && !BO->isIntDivRem() && !BO->isShift()) {
TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, UndefElts,
Depth + 1);
if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
TmpV = SimplifyDemandedVectorElts(I->getOperand(1), DemandedElts,
UndefElts2, Depth + 1);
if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; }
// TODO: If this is a potentially poison-producing instruction, we need
// to drop the wrapping/exact flags?
// Output elements are undefined if both are undefined. Consider things
// like undef&0. The result is known zero, not undef.
UndefElts &= UndefElts2;
}
return MadeChange ? I : nullptr;
}

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@ -1709,7 +1709,7 @@ define double @test_mask3_vfmsub_sd_1(<2 x double> %a, <2 x double> %b, <2 x dou
define <4 x float> @test_mask3_vfnmsub_ss(<4 x float> %a, <4 x float> %b, <4 x float> %c, i8 %mask) {
; CHECK-LABEL: @test_mask3_vfnmsub_ss(
; CHECK-NEXT: [[DOTRHS:%.*]] = extractelement <4 x float> [[A:%.*]], i32 0
; CHECK-NEXT: [[DOTRHS:%.*]] = extractelement <4 x float> [[A:%.*]], i64 0
; CHECK-NEXT: [[TMP1:%.*]] = fsub float -0.000000e+00, [[DOTRHS]]
; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x float> [[B:%.*]], i32 0
; CHECK-NEXT: [[DOTRHS1:%.*]] = extractelement <4 x float> [[C:%.*]], i64 0

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@ -348,7 +348,7 @@ define <4 x float> @fadd(<4 x float> %v) {
define <4 x double> @fsub(<4 x double> %v) {
; CHECK-LABEL: @fsub(
; CHECK-NEXT: [[B:%.*]] = fsub <4 x double> <double 4.100000e+01, double 4.200000e+01, double 4.300000e+01, double 4.400000e+01>, [[V:%.*]]
; CHECK-NEXT: [[B:%.*]] = fsub <4 x double> <double undef, double undef, double 4.300000e+01, double 4.400000e+01>, [[V:%.*]]
; CHECK-NEXT: [[S:%.*]] = shufflevector <4 x double> [[V]], <4 x double> [[B]], <4 x i32> <i32 undef, i32 1, i32 6, i32 7>
; CHECK-NEXT: ret <4 x double> [[S]]
;
@ -371,7 +371,7 @@ define <4 x float> @fmul(<4 x float> %v) {
define <4 x double> @fdiv_constant_op0(<4 x double> %v) {
; CHECK-LABEL: @fdiv_constant_op0(
; CHECK-NEXT: [[B:%.*]] = fdiv fast <4 x double> <double 4.100000e+01, double 4.200000e+01, double 4.300000e+01, double 4.400000e+01>, [[V:%.*]]
; CHECK-NEXT: [[B:%.*]] = fdiv fast <4 x double> <double undef, double undef, double 4.300000e+01, double 4.400000e+01>, [[V:%.*]]
; CHECK-NEXT: [[S:%.*]] = shufflevector <4 x double> [[V]], <4 x double> [[B]], <4 x i32> <i32 undef, i32 1, i32 6, i32 7>
; CHECK-NEXT: ret <4 x double> [[S]]
;
@ -392,7 +392,7 @@ define <4 x double> @fdiv_constant_op1(<4 x double> %v) {
define <4 x double> @frem(<4 x double> %v) {
; CHECK-LABEL: @frem(
; CHECK-NEXT: [[B:%.*]] = frem <4 x double> <double 4.100000e+01, double 4.200000e+01, double 4.300000e+01, double 4.400000e+01>, [[V:%.*]]
; CHECK-NEXT: [[B:%.*]] = frem <4 x double> <double 4.100000e+01, double 4.200000e+01, double undef, double undef>, [[V:%.*]]
; CHECK-NEXT: [[S:%.*]] = shufflevector <4 x double> [[B]], <4 x double> [[V]], <4 x i32> <i32 0, i32 1, i32 6, i32 7>
; CHECK-NEXT: ret <4 x double> [[S]]
;
@ -791,8 +791,8 @@ define <4 x double> @fdiv_fdiv(<4 x double> %v0) {
define <4 x double> @frem_frem(<4 x double> %v0) {
; CHECK-LABEL: @frem_frem(
; CHECK-NEXT: [[T1:%.*]] = frem <4 x double> <double 1.000000e+00, double 2.000000e+00, double 3.000000e+00, double 4.000000e+00>, [[V0:%.*]]
; CHECK-NEXT: [[T2:%.*]] = frem <4 x double> [[V0]], <double 5.000000e+00, double 6.000000e+00, double 7.000000e+00, double 8.000000e+00>
; CHECK-NEXT: [[T1:%.*]] = frem <4 x double> <double 1.000000e+00, double 2.000000e+00, double undef, double undef>, [[V0:%.*]]
; CHECK-NEXT: [[T2:%.*]] = frem <4 x double> [[V0]], <double undef, double undef, double 7.000000e+00, double 8.000000e+00>
; CHECK-NEXT: [[T3:%.*]] = shufflevector <4 x double> [[T1]], <4 x double> [[T2]], <4 x i32> <i32 0, i32 1, i32 6, i32 7>
; CHECK-NEXT: ret <4 x double> [[T3]]
;
@ -1284,8 +1284,8 @@ define <4 x double> @frem_2_vars(<4 x double> %v0, <4 x double> %v1) {
define <4 x double> @fdiv_2_vars(<4 x double> %v0, <4 x double> %v1) {
; CHECK-LABEL: @fdiv_2_vars(
; CHECK-NEXT: [[T1:%.*]] = fdiv <4 x double> <double 1.000000e+00, double 2.000000e+00, double 3.000000e+00, double 4.000000e+00>, [[V0:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fdiv <4 x double> [[V1:%.*]], <double 5.000000e+00, double 6.000000e+00, double 7.000000e+00, double 8.000000e+00>
; CHECK-NEXT: [[T1:%.*]] = fdiv <4 x double> <double 1.000000e+00, double 2.000000e+00, double undef, double undef>, [[V0:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fdiv <4 x double> [[V1:%.*]], <double undef, double undef, double 7.000000e+00, double 8.000000e+00>
; CHECK-NEXT: [[T3:%.*]] = shufflevector <4 x double> [[T1]], <4 x double> [[T2]], <4 x i32> <i32 0, i32 1, i32 6, i32 7>
; CHECK-NEXT: ret <4 x double> [[T3]]
;

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@ -421,7 +421,7 @@ define <3 x i8> @shuf_urem_const_op1(<3 x i8> %x) {
define <3 x float> @shuf_fadd(<3 x float> %x) {
; CHECK-LABEL: @shuf_fadd(
; CHECK-NEXT: [[BO:%.*]] = fadd <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>
; CHECK-NEXT: [[BO:%.*]] = fadd <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 1, i32 0>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -432,7 +432,7 @@ define <3 x float> @shuf_fadd(<3 x float> %x) {
define <3 x float> @shuf_fsub(<3 x float> %x) {
; CHECK-LABEL: @shuf_fsub(
; CHECK-NEXT: [[BO:%.*]] = fsub fast <3 x float> <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[BO:%.*]] = fsub fast <3 x float> <float 1.000000e+00, float undef, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 0, i32 2>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -443,7 +443,7 @@ define <3 x float> @shuf_fsub(<3 x float> %x) {
define <3 x float> @shuf_fmul(<3 x float> %x) {
; CHECK-LABEL: @shuf_fmul(
; CHECK-NEXT: [[BO:%.*]] = fmul reassoc <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>
; CHECK-NEXT: [[BO:%.*]] = fmul reassoc <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 1, i32 0>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -454,7 +454,7 @@ define <3 x float> @shuf_fmul(<3 x float> %x) {
define <3 x float> @shuf_fdiv_const_op0(<3 x float> %x) {
; CHECK-LABEL: @shuf_fdiv_const_op0(
; CHECK-NEXT: [[BO:%.*]] = fdiv reassoc ninf <3 x float> <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[BO:%.*]] = fdiv reassoc ninf <3 x float> <float 1.000000e+00, float undef, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 0, i32 2>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -465,7 +465,7 @@ define <3 x float> @shuf_fdiv_const_op0(<3 x float> %x) {
define <3 x float> @shuf_fdiv_const_op1(<3 x float> %x) {
; CHECK-LABEL: @shuf_fdiv_const_op1(
; CHECK-NEXT: [[BO:%.*]] = fdiv nnan ninf <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>
; CHECK-NEXT: [[BO:%.*]] = fdiv nnan ninf <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 1, i32 0>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -476,7 +476,7 @@ define <3 x float> @shuf_fdiv_const_op1(<3 x float> %x) {
define <3 x float> @shuf_frem_const_op0(<3 x float> %x) {
; CHECK-LABEL: @shuf_frem_const_op0(
; CHECK-NEXT: [[BO:%.*]] = frem nnan <3 x float> <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[BO:%.*]] = frem nnan <3 x float> <float 1.000000e+00, float undef, float 3.000000e+00>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 undef, i32 2, i32 0>
; CHECK-NEXT: ret <3 x float> [[R]]
;
@ -487,7 +487,7 @@ define <3 x float> @shuf_frem_const_op0(<3 x float> %x) {
define <3 x float> @shuf_frem_const_op1(<3 x float> %x) {
; CHECK-LABEL: @shuf_frem_const_op1(
; CHECK-NEXT: [[BO:%.*]] = frem reassoc ninf <3 x float> [[X:%.*]], <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00>
; CHECK-NEXT: [[BO:%.*]] = frem reassoc ninf <3 x float> [[X:%.*]], <float undef, float 2.000000e+00, float 3.000000e+00>
; CHECK-NEXT: [[R:%.*]] = shufflevector <3 x float> [[BO]], <3 x float> undef, <3 x i32> <i32 1, i32 undef, i32 2>
; CHECK-NEXT: ret <3 x float> [[R]]
;

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@ -952,7 +952,7 @@ define <2 x float> @fsub_splat_constant0(<2 x float> %x) {
define <2 x float> @fsub_splat_constant1(<2 x float> %x) {
; CHECK-LABEL: @fsub_splat_constant1(
; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float -4.200000e+01, float 0x7FF8000000000000>
; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float -4.200000e+01, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;