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author | Nuno Lopes <nunoplopes@sapo.pt> | 2009-11-12 14:53:53 +0000 |
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committer | Nuno Lopes <nunoplopes@sapo.pt> | 2009-11-12 14:53:53 +0000 |
commit | 34e992da381bf8b1a9cbcc1bde0b117207809649 (patch) | |
tree | bfc6711fceabd3619aa75a783f1e54a598aacceb | |
parent | 9e3728be625503e7145fa7c94735bd1878be9038 (diff) | |
download | llvm-34e992da381bf8b1a9cbcc1bde0b117207809649.tar.gz llvm-34e992da381bf8b1a9cbcc1bde0b117207809649.tar.bz2 llvm-34e992da381bf8b1a9cbcc1bde0b117207809649.tar.xz |
implement shl, ashr, and lshr methods. shl is not fully implemented as it is quite tricky.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86986 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | include/llvm/Support/ConstantRange.h | 12 | ||||
-rw-r--r-- | lib/Support/ConstantRange.cpp | 37 |
2 files changed, 49 insertions, 0 deletions
diff --git a/include/llvm/Support/ConstantRange.h b/include/llvm/Support/ConstantRange.h index 438ec143e8..6342c6f1bd 100644 --- a/include/llvm/Support/ConstantRange.h +++ b/include/llvm/Support/ConstantRange.h @@ -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; diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp index a194ac4ff5..4593eb9dff 100644 --- a/lib/Support/ConstantRange.cpp +++ b/lib/Support/ConstantRange.cpp @@ -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 { |