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| author | Nikita Popov <nikita.ppv@gmail.com> | 2021-04-14 19:04:01 +0200 |
|---|---|---|
| committer | Nikita Popov <nikita.ppv@gmail.com> | 2021-04-14 19:06:18 +0200 |
| commit | 5c0fb026c93b33dd107f6ff50723d7eed911e1ce (patch) | |
| tree | 7387cf5567bc406361e77de202b107b422a50f1d /llvm/lib/Analysis/ValueTracking.cpp | |
| parent | f1bc1a82cf718a67d3271fc74c28f5845f0f1526 (diff) | |
| download | llvm-5c0fb026c93b33dd107f6ff50723d7eed911e1ce.zip llvm-5c0fb026c93b33dd107f6ff50723d7eed911e1ce.tar.gz llvm-5c0fb026c93b33dd107f6ff50723d7eed911e1ce.tar.bz2 | |
[ValueTracking] Don't require non-zero step for add nuw
It's okay if the step is zero, we'll just stay at the same non-zero
value in that case. The valuable part of this is that the step
doesn't even need to be a constant anymore.
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index d78acdb..c1e7cf7 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -2227,11 +2227,9 @@ static bool isNonZeroRecurrence(const PHINode *PN) { case Instruction::Add: // Starting from non-zero and stepping away from zero can never wrap back // to zero. - // TODO: The constant step requirement is not needed with NUW. - return match(Step, m_APInt(StepC)) && - ((BO->hasNoUnsignedWrap() && !StepC->isNullValue()) || - (BO->hasNoSignedWrap() && - StartC->isNegative() == StepC->isNegative())); + return BO->hasNoUnsignedWrap() || + (BO->hasNoSignedWrap() && match(Step, m_APInt(StepC)) && + StartC->isNegative() == StepC->isNegative()); case Instruction::Mul: return match(Step, m_APInt(StepC)) && ((BO->hasNoUnsignedWrap() && !StepC->isNullValue()) || |