[ValueTracking] allow undef elements when matching vector abs

llvm-svn: 336111
This commit is contained in:
Sanjay Patel 2018-07-02 14:43:40 +00:00
parent d414c6c131
commit 284ba0c18f
2 changed files with 31 additions and 36 deletions

View File

@ -4605,39 +4605,34 @@ static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred,
}
}
const APInt *C1;
if (match(CmpRHS, m_APInt(C1))) {
// Sign-extending LHS does not change its sign, so TrueVal/FalseVal can
// match against either LHS or sext(LHS).
auto MaybeSExtLHS = m_CombineOr(m_Specific(CmpLHS),
m_SExt(m_Specific(CmpLHS)));
if ((match(TrueVal, MaybeSExtLHS) &&
match(FalseVal, m_Neg(m_Specific(TrueVal)))) ||
(match(FalseVal, MaybeSExtLHS) &&
match(TrueVal, m_Neg(m_Specific(FalseVal))))) {
// Set LHS and RHS so that RHS is the negated operand of the select
if (match(TrueVal, MaybeSExtLHS)) {
LHS = TrueVal;
RHS = FalseVal;
} else {
LHS = FalseVal;
RHS = TrueVal;
}
// ABS(X) ==> (X >s 0) ? X : -X and (X >s -1) ? X : -X
// NABS(X) ==> (X >s 0) ? -X : X and (X >s -1) ? -X : X
if (Pred == ICmpInst::ICMP_SGT &&
(C1->isNullValue() || C1->isAllOnesValue())) {
return {(LHS == TrueVal) ? SPF_ABS : SPF_NABS, SPNB_NA, false};
}
// ABS(X) ==> (X <s 0) ? -X : X and (X <s 1) ? -X : X
// NABS(X) ==> (X <s 0) ? X : -X and (X <s 1) ? X : -X
if (Pred == ICmpInst::ICMP_SLT &&
(C1->isNullValue() || C1->isOneValue())) {
return {(LHS == FalseVal) ? SPF_ABS : SPF_NABS, SPNB_NA, false};
}
// Sign-extending LHS does not change its sign, so TrueVal/FalseVal can
// match against either LHS or sext(LHS).
auto MaybeSExtLHS = m_CombineOr(m_Specific(CmpLHS),
m_SExt(m_Specific(CmpLHS)));
if ((match(TrueVal, MaybeSExtLHS) &&
match(FalseVal, m_Neg(m_Specific(TrueVal)))) ||
(match(FalseVal, MaybeSExtLHS) &&
match(TrueVal, m_Neg(m_Specific(FalseVal))))) {
// Set LHS and RHS so that RHS is the negated operand of the select
if (match(TrueVal, MaybeSExtLHS)) {
LHS = TrueVal;
RHS = FalseVal;
} else {
LHS = FalseVal;
RHS = TrueVal;
}
// (X >s 0) ? X : -X or (X >s -1) ? X : -X --> ABS(X)
// (X >s 0) ? -X : X or (X >s -1) ? -X : X --> NABS(X)
if (Pred == ICmpInst::ICMP_SGT &&
match(CmpRHS, m_CombineOr(m_ZeroInt(), m_AllOnes())))
return {(LHS == TrueVal) ? SPF_ABS : SPF_NABS, SPNB_NA, false};
// (X <s 0) ? -X : X or (X <s 1) ? -X : X --> ABS(X)
// (X <s 0) ? X : -X or (X <s 1) ? X : -X --> NABS(X)
if (Pred == ICmpInst::ICMP_SLT &&
match(CmpRHS, m_CombineOr(m_ZeroInt(), m_One())))
return {(LHS == FalseVal) ? SPF_ABS : SPF_NABS, SPNB_NA, false};
}
if (CmpInst::isIntPredicate(Pred))

View File

@ -77,9 +77,9 @@ define <2 x i8> @abs_canonical_2(<2 x i8> %x) {
define <2 x i8> @abs_canonical_2_vec_undef_elts(<2 x i8> %x) {
; CHECK-LABEL: @abs_canonical_2_vec_undef_elts(
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt <2 x i8> [[X:%.*]], <i8 undef, i8 -1>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> [[X:%.*]], zeroinitializer
; CHECK-NEXT: [[NEG:%.*]] = sub <2 x i8> zeroinitializer, [[X]]
; CHECK-NEXT: [[ABS:%.*]] = select <2 x i1> [[CMP]], <2 x i8> [[X]], <2 x i8> [[NEG]]
; CHECK-NEXT: [[ABS:%.*]] = select <2 x i1> [[CMP]], <2 x i8> [[NEG]], <2 x i8> [[X]]
; CHECK-NEXT: ret <2 x i8> [[ABS]]
;
%cmp = icmp sgt <2 x i8> %x, <i8 undef, i8 -1>
@ -165,9 +165,9 @@ define <2 x i8> @nabs_canonical_2(<2 x i8> %x) {
define <2 x i8> @nabs_canonical_2_vec_undef_elts(<2 x i8> %x) {
; CHECK-LABEL: @nabs_canonical_2_vec_undef_elts(
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt <2 x i8> [[X:%.*]], <i8 -1, i8 undef>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> [[X:%.*]], zeroinitializer
; CHECK-NEXT: [[NEG:%.*]] = sub <2 x i8> zeroinitializer, [[X]]
; CHECK-NEXT: [[ABS:%.*]] = select <2 x i1> [[CMP]], <2 x i8> [[NEG]], <2 x i8> [[X]]
; CHECK-NEXT: [[ABS:%.*]] = select <2 x i1> [[CMP]], <2 x i8> [[X]], <2 x i8> [[NEG]]
; CHECK-NEXT: ret <2 x i8> [[ABS]]
;
%cmp = icmp sgt <2 x i8> %x, <i8 -1, i8 undef>