ConstantInt *C2I = dyn_cast<ConstantInt>(C2);
if (!C2I)
return false;
- return (C1I->isZero() || C1I->isOne()) && (C2I->isZero() || C2I->isOne());
+ if (!C1I->isZero() && !C2I->isZero()) // One side must be zero.
+ return false;
+ return C1I->isOne() || C1I->isAllOnesValue() ||
+ C2I->isOne() || C2I->isAllOnesValue();
}
/// FoldSelectIntoOp - Try fold the select into one of the operands to
Constant *C = GetSelectFoldableConstant(TVI);
Value *OOp = TVI->getOperand(2-OpToFold);
// Avoid creating select between 2 constants unless it's selecting
- // between 0 and 1.
+ // between 0, 1 and -1.
if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C);
InsertNewInstBefore(NewSel, SI);
Constant *C = GetSelectFoldableConstant(FVI);
Value *OOp = FVI->getOperand(2-OpToFold);
// Avoid creating select between 2 constants unless it's selecting
- // between 0 and 1.
+ // between 0, 1 and -1.
if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp);
InsertNewInstBefore(NewSel, SI);
}
+/// foldSelectICmpAnd - If one of the constants is zero (we know they can't
+/// both be) and we have an icmp instruction with zero, and we have an 'and'
+/// with the non-constant value and a power of two we can turn the select
+/// into a shift on the result of the 'and'.
+static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
+ ConstantInt *FalseVal,
+ InstCombiner::BuilderTy *Builder) {
+ const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
+ if (!IC || !IC->isEquality())
+ return 0;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(IC->getOperand(1)))
+ if (!C->isZero())
+ return 0;
+
+ ConstantInt *AndRHS;
+ Value *LHS = IC->getOperand(0);
+ if (LHS->getType() != SI.getType() ||
+ !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
+ return 0;
+
+ // If both select arms are non-zero see if we have a select of the form
+ // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
+ // for 'x ? 2^n : 0' and fix the thing up at the end.
+ ConstantInt *Offset = 0;
+ if (!TrueVal->isZero() && !FalseVal->isZero()) {
+ if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2())
+ Offset = FalseVal;
+ else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2())
+ Offset = TrueVal;
+ else
+ return 0;
+
+ // Adjust TrueVal and FalseVal to the offset.
+ TrueVal = ConstantInt::get(Builder->getContext(),
+ TrueVal->getValue() - Offset->getValue());
+ FalseVal = ConstantInt::get(Builder->getContext(),
+ FalseVal->getValue() - Offset->getValue());
+ }
+
+ // Make sure the mask in the 'and' and one of the select arms is a power of 2.
+ if (!AndRHS->getValue().isPowerOf2() ||
+ (!TrueVal->getValue().isPowerOf2() &&
+ !FalseVal->getValue().isPowerOf2()))
+ return 0;
+
+ // Determine which shift is needed to transform result of the 'and' into the
+ // desired result.
+ ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal;
+ unsigned ValZeros = ValC->getValue().logBase2();
+ unsigned AndZeros = AndRHS->getValue().logBase2();
+
+ Value *V = LHS;
+ if (ValZeros > AndZeros)
+ V = Builder->CreateShl(V, ValZeros - AndZeros);
+ else if (ValZeros < AndZeros)
+ V = Builder->CreateLShr(V, AndZeros - ValZeros);
+
+ // Okay, now we know that everything is set up, we just don't know whether we
+ // have a icmp_ne or icmp_eq and whether the true or false val is the zero.
+ bool ShouldNotVal = !TrueVal->isZero();
+ ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
+ if (ShouldNotVal)
+ V = Builder->CreateXor(V, ValC);
+
+ // Apply an offset if needed.
+ if (Offset)
+ V = Builder->CreateAdd(V, Offset);
+ return V;
+}
Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
Value *CondVal = SI.getCondition();
Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName());
return new SExtInst(NotCond, SI.getType());
}
-
- if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) {
- // If one of the constants is zero (we know they can't both be) and we
- // have an icmp instruction with zero, and we have an 'and' with the
- // non-constant value, eliminate this whole mess. This corresponds to
- // cases like this: ((X & 27) ? 27 : 0)
- if (TrueValC->isZero() || FalseValC->isZero())
- if (IC->isEquality() && isa<ConstantInt>(IC->getOperand(1)) &&
- cast<Constant>(IC->getOperand(1))->isNullValue())
- if (Instruction *ICA = dyn_cast<Instruction>(IC->getOperand(0)))
- if (ICA->getOpcode() == Instruction::And &&
- isa<ConstantInt>(ICA->getOperand(1)) &&
- (ICA->getOperand(1) == TrueValC ||
- ICA->getOperand(1) == FalseValC) &&
- cast<ConstantInt>(ICA->getOperand(1))->getValue().isPowerOf2()) {
- // Okay, now we know that everything is set up, we just don't
- // know whether we have a icmp_ne or icmp_eq and whether the
- // true or false val is the zero.
- bool ShouldNotVal = !TrueValC->isZero();
- ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
- Value *V = ICA;
- if (ShouldNotVal)
- V = Builder->CreateXor(V, ICA->getOperand(1));
- return ReplaceInstUsesWith(SI, V);
- }
- }
+
+ if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder))
+ return ReplaceInstUsesWith(SI, V);
}
// See if we are selecting two values based on a comparison of the two values.
Value *NegVal; // Compute -Z
if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) {
NegVal = ConstantExpr::getNeg(C);
+ } else if (SI.getType()->isFloatingPointTy()) {
+ NegVal = InsertNewInstBefore(
+ BinaryOperator::CreateFNeg(SubOp->getOperand(1),
+ "tmp"), SI);
} else {
NegVal = InsertNewInstBefore(
BinaryOperator::CreateNeg(SubOp->getOperand(1),
NewFalseOp, SI.getName() + ".p");
NewSel = InsertNewInstBefore(NewSel, SI);
- return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
+ if (SI.getType()->isFloatingPointTy())
+ return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
+ else
+ return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
}
}
}
projects / oota-llvm.git / blobdiff