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| author | Dan Gohman <gohman@apple.com> | 2010-04-13 16:51:03 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2010-04-13 16:51:03 +0000 |
| commit | 7ef0dc21639f227bb69d23ea5f2009d2de566d01 (patch) | |
| tree | 8b7d249708736ab1556784a1c928ba76a51d6345 /llvm/lib/Analysis | |
| parent | fe4b29180b85eee160a603c87b2fd2194af01a5c (diff) | |
| download | bcm5719-llvm-7ef0dc21639f227bb69d23ea5f2009d2de566d01.tar.gz bcm5719-llvm-7ef0dc21639f227bb69d23ea5f2009d2de566d01.zip | |
Teach ScalarEvolution to simplify smax and umax when it can prove
that one operand is always greater than another.
llvm-svn: 101142
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 307c83a2e1c..a9a444f93a2 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -2117,7 +2117,13 @@ ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { // so, delete one. Since we sorted the list, these values are required to // be adjacent. for (unsigned i = 0, e = Ops.size()-1; i != e; ++i) - if (Ops[i] == Ops[i+1]) { // X smax Y smax Y --> X smax Y + // X smax Y smax Y --> X smax Y + // X smax Y --> X, if X is always greater than Y + if (Ops[i] == Ops[i+1] || + isKnownPredicate(ICmpInst::ICMP_SGE, Ops[i], Ops[i+1])) { + Ops.erase(Ops.begin()+i+1, Ops.begin()+i+2); + --i; --e; + } else if (isKnownPredicate(ICmpInst::ICMP_SLE, Ops[i], Ops[i+1])) { Ops.erase(Ops.begin()+i, Ops.begin()+i+1); --i; --e; } @@ -2216,7 +2222,13 @@ ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { // so, delete one. Since we sorted the list, these values are required to // be adjacent. for (unsigned i = 0, e = Ops.size()-1; i != e; ++i) - if (Ops[i] == Ops[i+1]) { // X umax Y umax Y --> X umax Y + // X umax Y umax Y --> X umax Y + // X umax Y --> X, if X is always greater than Y + if (Ops[i] == Ops[i+1] || + isKnownPredicate(ICmpInst::ICMP_UGE, Ops[i], Ops[i+1])) { + Ops.erase(Ops.begin()+i+1, Ops.begin()+i+2); + --i; --e; + } else if (isKnownPredicate(ICmpInst::ICMP_ULE, Ops[i], Ops[i+1])) { Ops.erase(Ops.begin()+i, Ops.begin()+i+1); --i; --e; } |
