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implement shl, ashr, and lshr methods. shl is not fully implemented as it is quite tricky.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86986 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nuno Lopes 2009-11-12 14:53:53 +00:00
parent 9e3728be62
commit 34e992da38
2 changed files with 49 additions and 0 deletions
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12
include/llvm/Support/ConstantRange.h
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@ -217,6 +217,18 @@ public:
/// TODO: This isn't fully implemented yet.
ConstantRange udiv(const ConstantRange &Other) const;
/// shl - Return a new range representing the possible values resulting
/// from a left shift of a value in this range by the Amount value.
ConstantRange shl(const ConstantRange &Amount) const;
/// ashr - Return a new range representing the possible values resulting from
/// an arithmetic right shift of a value in this range by the Amount value.
ConstantRange ashr(const ConstantRange &Amount) const;
/// shr - Return a new range representing the possible values resulting
/// from a logical right shift of a value in this range by the Amount value.
ConstantRange lshr(const ConstantRange &Amount) const;
/// print - Print out the bounds to a stream...
///
void print(raw_ostream &OS) const;

37
lib/Support/ConstantRange.cpp
View File

@ -609,6 +609,43 @@ ConstantRange::udiv(const ConstantRange &RHS) const {
return ConstantRange(Lower, Upper);
}
ConstantRange
ConstantRange::shl(const ConstantRange &Amount) const {
if (isEmptySet())
return *this;
APInt min = getUnsignedMin() << Amount.getUnsignedMin();
APInt max = getUnsignedMax() << Amount.getUnsignedMax();
// there's no overflow!
APInt Zeros(sizeof(unsigned)*8, getUnsignedMax().countLeadingZeros());
if (Zeros.uge(Amount.getUnsignedMax()))
return ConstantRange(min, max);
// FIXME: implement the other tricky cases
return ConstantRange(getBitWidth());
}
ConstantRange
ConstantRange::ashr(const ConstantRange &Amount) const {
if (isEmptySet())
return *this;
APInt min = getUnsignedMax().ashr(Amount.getUnsignedMin());
APInt max = getUnsignedMin().ashr(Amount.getUnsignedMax());
return ConstantRange(min, max);
}
ConstantRange
ConstantRange::lshr(const ConstantRange &Amount) const {
if (isEmptySet())
return *this;
APInt min = getUnsignedMax().lshr(Amount.getUnsignedMin());
APInt max = getUnsignedMin().lshr(Amount.getUnsignedMax());
return ConstantRange(min, max);
}
/// print - Print out the bounds to a stream...
///
void ConstantRange::print(raw_ostream &OS) const {