///
static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
int &Offset) {
- assert(Val->getType()->isInteger(32) && "Unexpected allocation size type!");
+ assert(Val->getType()->isIntegerTy(32) && "Unexpected allocation size type!");
if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
Offset = CI->getZExtValue();
Scale = 0;
return Instruction::CastOps(Res);
}
-/// ValueRequiresCast - Return true if the cast from "V to Ty" actually results
-/// in any code being generated. It does not require codegen if V is simple
-/// enough or if the cast can be folded into other casts.
-bool InstCombiner::ValueRequiresCast(Instruction::CastOps opcode,const Value *V,
- const Type *Ty) {
+/// ShouldOptimizeCast - Return true if the cast from "V to Ty" actually
+/// results in any code being generated and is interesting to optimize out. If
+/// the cast can be eliminated by some other simple transformation, we prefer
+/// to do the simplification first.
+bool InstCombiner::ShouldOptimizeCast(Instruction::CastOps opc, const Value *V,
+ const Type *Ty) {
+ // Noop casts and casts of constants should be eliminated trivially.
if (V->getType() == Ty || isa<Constant>(V)) return false;
- // If this is another cast that can be eliminated, it isn't codegen either.
+ // If this is another cast that can be eliminated, we prefer to have it
+ // eliminated.
if (const CastInst *CI = dyn_cast<CastInst>(V))
- if (isEliminableCastPair(CI, opcode, Ty, TD))
+ if (isEliminableCastPair(CI, opc, Ty, TD))
return false;
+
+ // If this is a vector sext from a compare, then we don't want to break the
+ // idiom where each element of the extended vector is either zero or all ones.
+ if (opc == Instruction::SExt && isa<CmpInst>(V) && isa<VectorType>(Ty))
+ return false;
+
return true;
}
// zext (xor i1 X, true) to i32 --> xor (zext i1 X to i32), 1
Value *X;
- if (SrcI && SrcI->hasOneUse() && SrcI->getType()->isInteger(1) &&
+ if (SrcI && SrcI->hasOneUse() && SrcI->getType()->isIntegerTy(1) &&
match(SrcI, m_Not(m_Value(X))) &&
(!X->hasOneUse() || !isa<CmpInst>(X))) {
Value *New = Builder->CreateZExt(X, CI.getType());
Value *Src = CI.getOperand(0);
const Type *SrcTy = Src->getType(), *DestTy = CI.getType();
- // Canonicalize sign-extend from i1 to a select.
- if (Src->getType()->isInteger(1))
- return SelectInst::Create(Src,
- Constant::getAllOnesValue(CI.getType()),
- Constant::getNullValue(CI.getType()));
-
// Attempt to extend the entire input expression tree to the destination
// type. Only do this if the dest type is a simple type, don't convert the
// expression tree to something weird like i93 unless the source is also
ShAmt);
}
+ // If this input is a trunc from our destination, then turn sext(trunc(x))
+ // into shifts.
+ if (TruncInst *TI = dyn_cast<TruncInst>(Src))
+ if (TI->hasOneUse() && TI->getOperand(0)->getType() == DestTy) {
+ uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
+ uint32_t DestBitSize = DestTy->getScalarSizeInBits();
+
+ // We need to emit a shl + ashr to do the sign extend.
+ Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
+ Value *Res = Builder->CreateShl(TI->getOperand(0), ShAmt, "sext");
+ return BinaryOperator::CreateAShr(Res, ShAmt);
+ }
+
+
+ // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if signed
+ // (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed
+ {
+ ICmpInst::Predicate Pred; Value *CmpLHS; ConstantInt *CmpRHS;
+ if (match(Src, m_ICmp(Pred, m_Value(CmpLHS), m_ConstantInt(CmpRHS)))) {
+ // sext (x <s 0) to i32 --> x>>s31 true if signbit set.
+ // sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear.
+ if ((Pred == ICmpInst::ICMP_SLT && CmpRHS->isZero()) ||
+ (Pred == ICmpInst::ICMP_SGT && CmpRHS->isAllOnesValue())) {
+ Value *Sh = ConstantInt::get(CmpLHS->getType(),
+ CmpLHS->getType()->getScalarSizeInBits()-1);
+ Value *In = Builder->CreateAShr(CmpLHS, Sh, CmpLHS->getName()+".lobit");
+ if (In->getType() != CI.getType())
+ In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/, "tmp");
+
+ if (Pred == ICmpInst::ICMP_SGT)
+ In = Builder->CreateNot(In, In->getName()+".not");
+ return ReplaceInstUsesWith(CI, In);
+ }
+ }
+ }
+
+
// If the input is a shl/ashr pair of a same constant, then this is a sign
// extension from a smaller value. If we could trust arbitrary bitwidth
// integers, we could turn this into a truncate to the smaller bit and then
}
Instruction *InstCombiner::visitIntToPtr(IntToPtrInst &CI) {
- // If the source integer type is larger than the intptr_t type for
- // this target, do a trunc to the intptr_t type, then inttoptr of it. This
- // allows the trunc to be exposed to other transforms. Don't do this for
- // extending inttoptr's, because we don't know if the target sign or zero
- // extends to pointers.
- if (TD && CI.getOperand(0)->getType()->getScalarSizeInBits() >
- TD->getPointerSizeInBits()) {
- Value *P = Builder->CreateTrunc(CI.getOperand(0),
- TD->getIntPtrType(CI.getContext()), "tmp");
- return new IntToPtrInst(P, CI.getType());
+ // If the source integer type is not the intptr_t type for this target, do a
+ // trunc or zext to the intptr_t type, then inttoptr of it. This allows the
+ // cast to be exposed to other transforms.
+ if (TD) {
+ if (CI.getOperand(0)->getType()->getScalarSizeInBits() >
+ TD->getPointerSizeInBits()) {
+ Value *P = Builder->CreateTrunc(CI.getOperand(0),
+ TD->getIntPtrType(CI.getContext()), "tmp");
+ return new IntToPtrInst(P, CI.getType());
+ }
+ if (CI.getOperand(0)->getType()->getScalarSizeInBits() <
+ TD->getPointerSizeInBits()) {
+ Value *P = Builder->CreateZExt(CI.getOperand(0),
+ TD->getIntPtrType(CI.getContext()), "tmp");
+ return new IntToPtrInst(P, CI.getType());
+ }
}
if (Instruction *I = commonCastTransforms(CI))
}
Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
- // If the destination integer type is smaller than the intptr_t type for
- // this target, do a ptrtoint to intptr_t then do a trunc. This allows the
- // trunc to be exposed to other transforms. Don't do this for extending
- // ptrtoint's, because we don't know if the target sign or zero extends its
- // pointers.
- if (TD &&
- CI.getType()->getScalarSizeInBits() < TD->getPointerSizeInBits()) {
- Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
- TD->getIntPtrType(CI.getContext()),
- "tmp");
- return new TruncInst(P, CI.getType());
+ // If the destination integer type is not the intptr_t type for this target,
+ // do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
+ // to be exposed to other transforms.
+ if (TD) {
+ if (CI.getType()->getScalarSizeInBits() < TD->getPointerSizeInBits()) {
+ Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
+ TD->getIntPtrType(CI.getContext()),
+ "tmp");
+ return new TruncInst(P, CI.getType());
+ }
+ if (CI.getType()->getScalarSizeInBits() > TD->getPointerSizeInBits()) {
+ Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
+ TD->getIntPtrType(CI.getContext()),
+ "tmp");
+ return new ZExtInst(P, CI.getType());
+ }
}
return commonPointerCastTransforms(CI);
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