diff options
| author | David Majnemer <david.majnemer@gmail.com> | 2014-05-16 16:57:04 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2014-05-16 16:57:04 +0000 |
| commit | 7a2ed26563512149ea03e56d8ecd92c884c32f8f (patch) | |
| tree | 37246a33e39acba410dc42b9d097e70f8e7b58dc /lib/Analysis | |
| parent | 18fc3275c1ced483ca345c4912141e1ab3ed1920 (diff) | |
| download | llvm-7a2ed26563512149ea03e56d8ecd92c884c32f8f.tar.gz llvm-7a2ed26563512149ea03e56d8ecd92c884c32f8f.tar.bz2 llvm-7a2ed26563512149ea03e56d8ecd92c884c32f8f.tar.xz | |
InstSimplify: Optimize using dividend in sdiv
Summary:
The dividend in an sdiv tells us the largest and smallest possible
results. Use this fact to optimize comparisons against an sdiv with a
constant dividend.
Reviewers: nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D3795
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208999 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis')
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 5421a39922..4cad81b139 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -2020,6 +2020,10 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, APInt NegOne = APInt::getAllOnesValue(Width); if (!CI2->isZero()) Upper = NegOne.udiv(CI2->getValue()) + 1; + } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) { + // 'sdiv CI2, x' produces [-|CI2|, |CI2|]. + Upper = CI2->getValue().abs() + 1; + Lower = (-Upper) + 1; } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) { // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]. APInt IntMin = APInt::getSignedMinValue(Width); |