ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition());
if (!ICI) return SPF_UNKNOWN;
- LHS = ICI->getOperand(0);
- RHS = ICI->getOperand(1);
+ ICmpInst::Predicate Pred = ICI->getPredicate();
+ Value *CmpLHS = ICI->getOperand(0);
+ Value *CmpRHS = ICI->getOperand(1);
+ Value *TrueVal = SI->getTrueValue();
+ Value *FalseVal = SI->getFalseValue();
+
+ LHS = CmpLHS;
+ RHS = CmpRHS;
// (icmp X, Y) ? X : Y
- if (SI->getTrueValue() == ICI->getOperand(0) &&
- SI->getFalseValue() == ICI->getOperand(1)) {
- switch (ICI->getPredicate()) {
+ if (TrueVal == CmpLHS && FalseVal == CmpRHS) {
+ switch (Pred) {
default: return SPF_UNKNOWN; // Equality.
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE: return SPF_UMAX;
}
// (icmp X, Y) ? Y : X
- if (SI->getTrueValue() == ICI->getOperand(1) &&
- SI->getFalseValue() == ICI->getOperand(0)) {
- switch (ICI->getPredicate()) {
- default: return SPF_UNKNOWN; // Equality.
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_UGE: return SPF_UMIN;
- case ICmpInst::ICMP_SGT:
- case ICmpInst::ICMP_SGE: return SPF_SMIN;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_ULE: return SPF_UMAX;
- case ICmpInst::ICMP_SLT:
- case ICmpInst::ICMP_SLE: return SPF_SMAX;
+ if (TrueVal == CmpRHS && FalseVal == CmpLHS) {
+ switch (Pred) {
+ default: return SPF_UNKNOWN; // Equality.
+ case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE: return SPF_UMIN;
+ case ICmpInst::ICMP_SGT:
+ case ICmpInst::ICMP_SGE: return SPF_SMIN;
+ case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE: return SPF_UMAX;
+ case ICmpInst::ICMP_SLT:
+ case ICmpInst::ICMP_SLE: return SPF_SMAX;
+ }
+ }
+
+ if (ConstantInt *C1 = dyn_cast<ConstantInt>(CmpRHS)) {
+ if ((CmpLHS == TrueVal && match(FalseVal, m_Neg(m_Specific(CmpLHS)))) ||
+ (CmpLHS == FalseVal && match(TrueVal, m_Neg(m_Specific(CmpLHS))))) {
+
+ // 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->isZero() || C1->isMinusOne())) {
+ return (CmpLHS == TrueVal) ? SPF_ABS : SPF_NABS;
+ }
+
+ // 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->isZero() || C1->isOne())) {
+ return (CmpLHS == FalseVal) ? SPF_ABS : SPF_NABS;
+ }
}
}
}
}
}
+
+ // ABS(ABS(X)) -> ABS(X)
+ // NABS(NABS(X)) -> NABS(X)
+ if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) {
+ return ReplaceInstUsesWith(Outer, Inner);
+ }
+
+ // TODO: ABS(NABS(X)) -> ABS(X)
+ // TODO: NABS(ABS(X)) -> NABS(X)
return nullptr;
}
// TODO.
// ABS(-X) -> ABS(X)
- // ABS(ABS(X)) -> ABS(X)
}
// See if we can fold the select into a phi node if the condition is a select.