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| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2024-03-05 22:03:44 -0600 |
|---|---|---|
| committer | Noah Goldstein <goldstein.w.n@gmail.com> | 2024-03-11 15:51:07 -0500 |
| commit | d81db0e5f5b1404ff4813af3050d671528ad45cc (patch) | |
| tree | 4fa74264813641b7cde900b7a803b7fb64bfa538 /llvm/unittests/Support/KnownBitsTest.cpp | |
| parent | a9d913ebcd567ad14ffdc8c8684c4f0611e1e2da (diff) | |
| download | llvm-d81db0e5f5b1404ff4813af3050d671528ad45cc.zip llvm-d81db0e5f5b1404ff4813af3050d671528ad45cc.tar.gz llvm-d81db0e5f5b1404ff4813af3050d671528ad45cc.tar.bz2 | |
[KnownBits] Implement knownbits `lshr`/`ashr` with exact flag
The exact flag basically allows us to set an upper bound on shift
amount when we have a known 1 in `LHS`.
Typically we deduce exact using knownbits (on non-exact incoming
shifts), so this is particularly impactful, but may be useful in some
circumstances.
Closes #84254
Diffstat (limited to 'llvm/unittests/Support/KnownBitsTest.cpp')
| -rw-r--r-- | llvm/unittests/Support/KnownBitsTest.cpp | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/llvm/unittests/Support/KnownBitsTest.cpp b/llvm/unittests/Support/KnownBitsTest.cpp index 658f379..7c183e9 100644 --- a/llvm/unittests/Support/KnownBitsTest.cpp +++ b/llvm/unittests/Support/KnownBitsTest.cpp @@ -518,6 +518,19 @@ TEST(KnownBitsTest, BinaryExhaustive) { checkOptimalityBinary, /* RefinePoisonToZero */ true); testBinaryOpExhaustive( [](const KnownBits &Known1, const KnownBits &Known2) { + return KnownBits::lshr(Known1, Known2, /*ShAmtNonZero=*/false, + /*Exact=*/true); + }, + [](const APInt &N1, const APInt &N2) -> std::optional<APInt> { + if (N2.uge(N2.getBitWidth())) + return std::nullopt; + if (!N1.extractBits(N2.getZExtValue(), 0).isZero()) + return std::nullopt; + return N1.lshr(N2); + }, + checkOptimalityBinary, /* RefinePoisonToZero */ true); + testBinaryOpExhaustive( + [](const KnownBits &Known1, const KnownBits &Known2) { return KnownBits::ashr(Known1, Known2); }, [](const APInt &N1, const APInt &N2) -> std::optional<APInt> { @@ -526,6 +539,19 @@ TEST(KnownBitsTest, BinaryExhaustive) { return N1.ashr(N2); }, checkOptimalityBinary, /* RefinePoisonToZero */ true); + testBinaryOpExhaustive( + [](const KnownBits &Known1, const KnownBits &Known2) { + return KnownBits::ashr(Known1, Known2, /*ShAmtNonZero=*/false, + /*Exact=*/true); + }, + [](const APInt &N1, const APInt &N2) -> std::optional<APInt> { + if (N2.uge(N2.getBitWidth())) + return std::nullopt; + if (!N1.extractBits(N2.getZExtValue(), 0).isZero()) + return std::nullopt; + return N1.ashr(N2); + }, + checkOptimalityBinary, /* RefinePoisonToZero */ true); testBinaryOpExhaustive( [](const KnownBits &Known1, const KnownBits &Known2) { |