+++ /dev/null
-//===-- ConstantRange.cpp - ConstantRange implementation ------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Represent a range of possible values that may occur when the program is run
-// for an integral value. This keeps track of a lower and upper bound for the
-// constant, which MAY wrap around the end of the numeric range. To do this, it
-// keeps track of a [lower, upper) bound, which specifies an interval just like
-// STL iterators. When used with boolean values, the following are important
-// ranges (other integral ranges use min/max values for special range values):
-//
-// [F, F) = {} = Empty set
-// [T, F) = {T}
-// [F, T) = {F}
-// [T, T) = {F, T} = Full set
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Support/ConstantRange.h"
-#include "llvm/Constants.h"
-#include "llvm/Instruction.h"
-#include "llvm/Type.h"
-#include <iostream>
-
-using namespace llvm;
-
-static ConstantIntegral *Next(ConstantIntegral *CI) {
- if (CI->getType() == Type::BoolTy)
- return CI == ConstantBool::True ? ConstantBool::False : ConstantBool::True;
-
- Constant *Result = ConstantExpr::getAdd(CI,
- ConstantInt::get(CI->getType(), 1));
- return cast<ConstantIntegral>(Result);
-}
-
-static bool LT(ConstantIntegral *A, ConstantIntegral *B) {
- Constant *C = ConstantExpr::getSetLT(A, B);
- assert(isa<ConstantBool>(C) && "Constant folding of integrals not impl??");
- return cast<ConstantBool>(C)->getValue();
-}
-
-static bool LTE(ConstantIntegral *A, ConstantIntegral *B) {
- Constant *C = ConstantExpr::getSetLE(A, B);
- assert(isa<ConstantBool>(C) && "Constant folding of integrals not impl??");
- return cast<ConstantBool>(C)->getValue();
-}
-
-static bool GT(ConstantIntegral *A, ConstantIntegral *B) { return LT(B, A); }
-
-static ConstantIntegral *Min(ConstantIntegral *A, ConstantIntegral *B) {
- return LT(A, B) ? A : B;
-}
-static ConstantIntegral *Max(ConstantIntegral *A, ConstantIntegral *B) {
- return GT(A, B) ? A : B;
-}
-
-/// Initialize a full (the default) or empty set for the specified type.
-///
-ConstantRange::ConstantRange(const Type *Ty, bool Full) {
- assert(Ty->isIntegral() &&
- "Cannot make constant range of non-integral type!");
- if (Full)
- Lower = Upper = ConstantIntegral::getMaxValue(Ty);
- else
- Lower = Upper = ConstantIntegral::getMinValue(Ty);
-}
-
-/// Initialize a range to hold the single specified value.
-///
-ConstantRange::ConstantRange(Constant *V)
- : Lower(cast<ConstantIntegral>(V)), Upper(Next(cast<ConstantIntegral>(V))) {
-}
-
-/// Initialize a range of values explicitly... this will assert out if
-/// Lower==Upper and Lower != Min or Max for its type (or if the two constants
-/// have different types)
-///
-ConstantRange::ConstantRange(Constant *L, Constant *U)
- : Lower(cast<ConstantIntegral>(L)), Upper(cast<ConstantIntegral>(U)) {
- assert(Lower->getType() == Upper->getType() &&
- "Incompatible types for ConstantRange!");
-
- // Make sure that if L & U are equal that they are either Min or Max...
- assert((L != U || (L == ConstantIntegral::getMaxValue(L->getType()) ||
- L == ConstantIntegral::getMinValue(L->getType()))) &&
- "Lower == Upper, but they aren't min or max for type!");
-}
-
-/// Initialize a set of values that all satisfy the condition with C.
-///
-ConstantRange::ConstantRange(unsigned SetCCOpcode, ConstantIntegral *C) {
- switch (SetCCOpcode) {
- default: assert(0 && "Invalid SetCC opcode to ConstantRange ctor!");
- case Instruction::SetEQ: Lower = C; Upper = Next(C); return;
- case Instruction::SetNE: Upper = C; Lower = Next(C); return;
- case Instruction::SetLT:
- Lower = ConstantIntegral::getMinValue(C->getType());
- Upper = C;
- return;
- case Instruction::SetGT:
- Lower = Next(C);
- Upper = ConstantIntegral::getMinValue(C->getType()); // Min = Next(Max)
- return;
- case Instruction::SetLE:
- Lower = ConstantIntegral::getMinValue(C->getType());
- Upper = Next(C);
- return;
- case Instruction::SetGE:
- Lower = C;
- Upper = ConstantIntegral::getMinValue(C->getType()); // Min = Next(Max)
- return;
- }
-}
-
-/// getType - Return the LLVM data type of this range.
-///
-const Type *ConstantRange::getType() const { return Lower->getType(); }
-
-/// isFullSet - Return true if this set contains all of the elements possible
-/// for this data-type
-bool ConstantRange::isFullSet() const {
- return Lower == Upper && Lower == ConstantIntegral::getMaxValue(getType());
-}
-
-/// isEmptySet - Return true if this set contains no members.
-///
-bool ConstantRange::isEmptySet() const {
- return Lower == Upper && Lower == ConstantIntegral::getMinValue(getType());
-}
-
-/// isWrappedSet - Return true if this set wraps around the top of the range,
-/// for example: [100, 8)
-///
-bool ConstantRange::isWrappedSet() const {
- return GT(Lower, Upper);
-}
-
-
-/// getSingleElement - If this set contains a single element, return it,
-/// otherwise return null.
-ConstantIntegral *ConstantRange::getSingleElement() const {
- if (Upper == Next(Lower)) // Is it a single element range?
- return Lower;
- return 0;
-}
-
-/// getSetSize - Return the number of elements in this set.
-///
-uint64_t ConstantRange::getSetSize() const {
- if (isEmptySet()) return 0;
- if (getType() == Type::BoolTy) {
- if (Lower != Upper) // One of T or F in the set...
- return 1;
- return 2; // Must be full set...
- }
-
- // Simply subtract the bounds...
- Constant *Result = ConstantExpr::getSub(Upper, Lower);
- return cast<ConstantInt>(Result)->getRawValue();
-}
-
-/// contains - Return true if the specified value is in the set.
-///
-bool ConstantRange::contains(ConstantInt *Val) const {
- if (Lower == Upper) {
- if (isFullSet()) return true;
- return false;
- }
-
- if (!isWrappedSet())
- return LTE(Lower, Val) && LT(Val, Upper);
- return LTE(Lower, Val) || LT(Val, Upper);
-}
-
-
-
-/// subtract - Subtract the specified constant from the endpoints of this
-/// constant range.
-ConstantRange ConstantRange::subtract(ConstantInt *CI) const {
- assert(CI->getType() == getType() && getType()->isInteger() &&
- "Cannot subtract from different type range or non-integer!");
- // If the set is empty or full, don't modify the endpoints.
- if (Lower == Upper) return *this;
- return ConstantRange(ConstantExpr::getSub(Lower, CI),
- ConstantExpr::getSub(Upper, CI));
-}
-
-
-// intersect1Wrapped - This helper function is used to intersect two ranges when
-// it is known that LHS is wrapped and RHS isn't.
-//
-static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
- const ConstantRange &RHS) {
- assert(LHS.isWrappedSet() && !RHS.isWrappedSet());
-
- // Check to see if we overlap on the Left side of RHS...
- //
- if (LT(RHS.getLower(), LHS.getUpper())) {
- // We do overlap on the left side of RHS, see if we overlap on the right of
- // RHS...
- if (GT(RHS.getUpper(), LHS.getLower())) {
- // Ok, the result overlaps on both the left and right sides. See if the
- // resultant interval will be smaller if we wrap or not...
- //
- if (LHS.getSetSize() < RHS.getSetSize())
- return LHS;
- else
- return RHS;
-
- } else {
- // No overlap on the right, just on the left.
- return ConstantRange(RHS.getLower(), LHS.getUpper());
- }
-
- } else {
- // We don't overlap on the left side of RHS, see if we overlap on the right
- // of RHS...
- if (GT(RHS.getUpper(), LHS.getLower())) {
- // Simple overlap...
- return ConstantRange(LHS.getLower(), RHS.getUpper());
- } else {
- // No overlap...
- return ConstantRange(LHS.getType(), false);
- }
- }
-}
-
-/// intersect - Return the range that results from the intersection of this
-/// range with another range.
-///
-ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
- assert(getType() == CR.getType() && "ConstantRange types don't agree!");
- // Handle common special cases
- if (isEmptySet() || CR.isFullSet()) return *this;
- if (isFullSet() || CR.isEmptySet()) return CR;
-
- if (!isWrappedSet()) {
- if (!CR.isWrappedSet()) {
- ConstantIntegral *L = Max(Lower, CR.Lower);
- ConstantIntegral *U = Min(Upper, CR.Upper);
-
- if (LT(L, U)) // If range isn't empty...
- return ConstantRange(L, U);
- else
- return ConstantRange(getType(), false); // Otherwise, return empty set
- } else
- return intersect1Wrapped(CR, *this);
- } else { // We know "this" is wrapped...
- if (!CR.isWrappedSet())
- return intersect1Wrapped(*this, CR);
- else {
- // Both ranges are wrapped...
- ConstantIntegral *L = Max(Lower, CR.Lower);
- ConstantIntegral *U = Min(Upper, CR.Upper);
- return ConstantRange(L, U);
- }
- }
- return *this;
-}
-
-/// union - Return the range that results from the union of this range with
-/// another range. The resultant range is guaranteed to include the elements of
-/// both sets, but may contain more. For example, [3, 9) union [12,15) is [3,
-/// 15), which includes 9, 10, and 11, which were not included in either set
-/// before.
-///
-ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
- assert(getType() == CR.getType() && "ConstantRange types don't agree!");
-
- assert(0 && "Range union not implemented yet!");
-
- return *this;
-}
-
-/// zeroExtend - Return a new range in the specified integer type, which must
-/// be strictly larger than the current type. The returned range will
-/// correspond to the possible range of values if the source range had been
-/// zero extended.
-ConstantRange ConstantRange::zeroExtend(const Type *Ty) const {
- assert(getLower()->getType()->getPrimitiveSize() < Ty->getPrimitiveSize() &&
- "Not a value extension");
- if (isFullSet()) {
- // Change a source full set into [0, 1 << 8*numbytes)
- unsigned SrcTySize = getLower()->getType()->getPrimitiveSize();
- return ConstantRange(Constant::getNullValue(Ty),
- ConstantUInt::get(Ty, 1ULL << SrcTySize*8));
- }
-
- Constant *Lower = getLower();
- Constant *Upper = getUpper();
- if (Lower->getType()->isInteger() && !Lower->getType()->isUnsigned()) {
- // Ensure we are doing a ZERO extension even if the input range is signed.
- Lower = ConstantExpr::getCast(Lower, Ty->getUnsignedVersion());
- Upper = ConstantExpr::getCast(Upper, Ty->getUnsignedVersion());
- }
-
- return ConstantRange(ConstantExpr::getCast(Lower, Ty),
- ConstantExpr::getCast(Upper, Ty));
-}
-
-/// truncate - Return a new range in the specified integer type, which must be
-/// strictly smaller than the current type. The returned range will
-/// correspond to the possible range of values if the source range had been
-/// truncated to the specified type.
-ConstantRange ConstantRange::truncate(const Type *Ty) const {
- assert(getLower()->getType()->getPrimitiveSize() > Ty->getPrimitiveSize() &&
- "Not a value truncation");
- uint64_t Size = 1ULL << Ty->getPrimitiveSize()*8;
- if (isFullSet() || getSetSize() >= Size)
- return ConstantRange(getType());
-
- return ConstantRange(ConstantExpr::getCast(getLower(), Ty),
- ConstantExpr::getCast(getUpper(), Ty));
-}
-
-
-/// print - Print out the bounds to a stream...
-///
-void ConstantRange::print(std::ostream &OS) const {
- OS << "[" << *Lower << "," << *Upper << " )";
-}
-
-/// dump - Allow printing from a debugger easily...
-///
-void ConstantRange::dump() const {
- print(std::cerr);
-}
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