factor the code for simplifying (icmp)|(icmp) into its own function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59402 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-11-16 05:20:07 +00:00
parent aa3e157845
commit 69d4ced68d

View File

@ -182,6 +182,7 @@ namespace {
Instruction *visitFDiv(BinaryOperator &I);
Instruction *FoldAndOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
Instruction *visitAnd(BinaryOperator &I);
Instruction *FoldOrOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
Instruction *visitOr (BinaryOperator &I);
Instruction *visitXor(BinaryOperator &I);
Instruction *visitShl(BinaryOperator &I);
@ -3695,7 +3696,7 @@ Instruction *InstCombiner::FoldAndOfICmps(Instruction &I,
if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
return new ICmpInst(LHSCC, Val, RHSCst);
break; // (X u> 13 & X != 15) -> no change
case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) ->(X-14) <u 1
case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true, I);
case ICmpInst::ICMP_SLT: // (X u> 13 & X s< 15) -> no change
break;
@ -3713,15 +3714,13 @@ Instruction *InstCombiner::FoldAndOfICmps(Instruction &I,
if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
return new ICmpInst(LHSCC, Val, RHSCst);
break; // (X s> 13 & X != 15) -> no change
case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) ->(X-14) s< 1
case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, true, true, I);
case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change
break;
}
break;
}
return 0;
}
@ -4237,6 +4236,167 @@ static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
return 0;
}
/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
Instruction *InstCombiner::FoldOrOfICmps(Instruction &I,
ICmpInst *LHS, ICmpInst *RHS) {
Value *Val, *Val2;
ConstantInt *LHSCst, *RHSCst;
ICmpInst::Predicate LHSCC, RHSCC;
// This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
if (!match(LHS, m_ICmp(LHSCC, m_Value(Val), m_ConstantInt(LHSCst))) ||
!match(RHS, m_ICmp(RHSCC, m_Value(Val2), m_ConstantInt(RHSCst))))
return 0;
// From here on, we only handle:
// (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
if (Val != Val2) return 0;
// ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
return 0;
// We can't fold (ugt x, C) | (sgt x, C2).
if (!PredicatesFoldable(LHSCC, RHSCC))
return 0;
// Ensure that the larger constant is on the RHS.
bool ShouldSwap;
if (ICmpInst::isSignedPredicate(LHSCC) ||
(ICmpInst::isEquality(LHSCC) &&
ICmpInst::isSignedPredicate(RHSCC)))
ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
else
ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
if (ShouldSwap) {
std::swap(LHS, RHS);
std::swap(LHSCst, RHSCst);
std::swap(LHSCC, RHSCC);
}
// At this point, we know we have have two icmp instructions
// comparing a value against two constants and or'ing the result
// together. Because of the above check, we know that we only have
// ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
// FoldICmpLogical check above), that the two constants are not
// equal.
assert(LHSCst != RHSCst && "Compares not folded above?");
switch (LHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ:
if (LHSCst == SubOne(RHSCst)) { // (X == 13 | X == 14) -> X-13 <u 2
Constant *AddCST = ConstantExpr::getNeg(LHSCst);
Instruction *Add = BinaryOperator::CreateAdd(Val, AddCST,
Val->getName()+".off");
InsertNewInstBefore(Add, I);
AddCST = Subtract(AddOne(RHSCst), LHSCst);
return new ICmpInst(ICmpInst::ICMP_ULT, Add, AddCST);
}
break; // (X == 13 | X == 15) -> no change
case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
break;
case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15
case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15
case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15
return ReplaceInstUsesWith(I, RHS);
}
break;
case ICmpInst::ICMP_NE:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13
case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13
case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true
case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true
case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
}
break;
case ICmpInst::ICMP_ULT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
// If RHSCst is [us]MAXINT, it is always false. Not handling
// this can cause overflow.
if (RHSCst->isMaxValue(false))
return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false, I);
case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15
case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15
return ReplaceInstUsesWith(I, RHS);
case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_SLT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
// If RHSCst is [us]MAXINT, it is always false. Not handling
// this can cause overflow.
if (RHSCst->isMaxValue(true))
return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false, I);
case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15
case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15
return ReplaceInstUsesWith(I, RHS);
case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_UGT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13
case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true
case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_SGT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13
case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true
case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change
break;
}
break;
}
return 0;
}
Instruction *InstCombiner::visitOr(BinaryOperator &I) {
bool Changed = SimplifyCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@ -4435,153 +4595,9 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
return R;
Value *Val;
ConstantInt *LHSCst, *RHSCst;
ICmpInst::Predicate LHSCC, RHSCC;
// (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
if (match(Op0, m_ICmp(LHSCC, m_Value(Val), m_ConstantInt(LHSCst))) &&
match(RHS, m_ICmp(RHSCC, m_Specific(Val), m_ConstantInt(RHSCst))) &&
// ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
LHSCC != ICmpInst::ICMP_UGE && LHSCC != ICmpInst::ICMP_ULE &&
RHSCC != ICmpInst::ICMP_UGE && RHSCC != ICmpInst::ICMP_ULE &&
LHSCC != ICmpInst::ICMP_SGE && LHSCC != ICmpInst::ICMP_SLE &&
RHSCC != ICmpInst::ICMP_SGE && RHSCC != ICmpInst::ICMP_SLE &&
// We can't fold (ugt x, C) | (sgt x, C2).
PredicatesFoldable(LHSCC, RHSCC)) {
// Ensure that the larger constant is on the RHS.
ICmpInst *LHS = cast<ICmpInst>(Op0);
bool NeedsSwap;
if (ICmpInst::isEquality(LHSCC) ? ICmpInst::isSignedPredicate(RHSCC)
: ICmpInst::isSignedPredicate(LHSCC))
NeedsSwap = LHSCst->getValue().sgt(RHSCst->getValue());
else
NeedsSwap = LHSCst->getValue().ugt(RHSCst->getValue());
if (NeedsSwap) {
std::swap(LHS, RHS);
std::swap(LHSCst, RHSCst);
std::swap(LHSCC, RHSCC);
}
// At this point, we know we have have two icmp instructions
// comparing a value against two constants and or'ing the result
// together. Because of the above check, we know that we only have
// ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
// FoldICmpLogical check above), that the two constants are not
// equal.
assert(LHSCst != RHSCst && "Compares not folded above?");
switch (LHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ:
if (LHSCst == SubOne(RHSCst)) { // (X == 13 | X == 14) -> X-13 <u 2
Constant *AddCST = ConstantExpr::getNeg(LHSCst);
Instruction *Add = BinaryOperator::CreateAdd(Val, AddCST,
Val->getName()+".off");
InsertNewInstBefore(Add, I);
AddCST = Subtract(AddOne(RHSCst), LHSCst);
return new ICmpInst(ICmpInst::ICMP_ULT, Add, AddCST);
}
break; // (X == 13 | X == 15) -> no change
case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
break;
case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15
case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15
case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15
return ReplaceInstUsesWith(I, RHS);
}
break;
case ICmpInst::ICMP_NE:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13
case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13
case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true
case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true
case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
}
break;
case ICmpInst::ICMP_ULT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
// If RHSCst is [us]MAXINT, it is always false. Not handling
// this can cause overflow.
if (RHSCst->isMaxValue(false))
return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false, I);
case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15
case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15
return ReplaceInstUsesWith(I, RHS);
case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_SLT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
// If RHSCst is [us]MAXINT, it is always false. Not handling
// this can cause overflow.
if (RHSCst->isMaxValue(true))
return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false, I);
case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15
case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15
return ReplaceInstUsesWith(I, RHS);
case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_UGT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13
case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true
case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change
break;
}
break;
case ICmpInst::ICMP_SGT:
switch (RHSCC) {
default: assert(0 && "Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13
case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13
return ReplaceInstUsesWith(I, LHS);
case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change
break;
case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true
case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change
break;
}
break;
}
}
if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
if (Instruction *Res = FoldOrOfICmps(I, LHS, RHS))
return Res;
}
// fold (or (cast A), (cast B)) -> (cast (or A, B))