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Strengthen icmp snuggling by doing 'compare-or-equal-to' to 'compare'

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first and then range testing second.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35715 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2007-04-07 02:30:14 +00:00
parent c4625da483
commit 8ac40dd747
1 changed files with 23 additions and 16 deletions
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39
lib/Transforms/Scalar/PredicateSimplifier.cpp
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@ -2182,11 +2182,33 @@ namespace {
// Eg., if x = [0, 4) and we're being asked icmp uge %x, 3 then change
// the predicate to eq.
// XXX: once we do full PHI handling, modifying the instruction in the
// Forwards visitor will cause missed optimizations.
ICmpInst::Predicate Pred = IC.getPredicate();
switch (Pred) {
default: break;
case ICmpInst::ICMP_ULE: Pred = ICmpInst::ICMP_ULT; break;
case ICmpInst::ICMP_UGE: Pred = ICmpInst::ICMP_UGT; break;
case ICmpInst::ICMP_SLE: Pred = ICmpInst::ICMP_SLT; break;
case ICmpInst::ICMP_SGE: Pred = ICmpInst::ICMP_SGT; break;
}
if (Pred != IC.getPredicate()) {
VRPSolver VRP(IG, UB, VR, PS->Forest, PS->modified, &IC);
if (VRP.isRelatedBy(IC.getOperand(1), IC.getOperand(0),
ICmpInst::ICMP_NE)) {
++NumSnuggle;
PS->modified = true;
IC.setPredicate(Pred);
}
}
Pred = IC.getPredicate();
if (ConstantInt *Op1 = dyn_cast<ConstantInt>(IC.getOperand(1))) {
ConstantInt *NextVal = 0;
switch(Pred) {
switch (Pred) {
default: break;
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_ULT:
@ -2214,24 +2236,9 @@ namespace {
IC.eraseFromParent();
++NumSnuggle;
PS->modified = true;
return;
}
}
}
switch(Pred) {
default: return;
case ICmpInst::ICMP_ULE: Pred = ICmpInst::ICMP_ULT; break;
case ICmpInst::ICMP_UGE: Pred = ICmpInst::ICMP_UGT; break;
case ICmpInst::ICMP_SLE: Pred = ICmpInst::ICMP_SLT; break;
case ICmpInst::ICMP_SGE: Pred = ICmpInst::ICMP_SGT; break;
}
VRPSolver VRP(IG, UB, VR, PS->Forest, PS->modified, &IC);
if (VRP.isRelatedBy(IC.getOperand(1), IC.getOperand(0), Pred)) {
++NumSnuggle;
PS->modified = true;
IC.setPredicate(Pred);
}
}
RegisterPass<PredicateSimplifier> X("predsimplify",