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Do not handle case where LHS is equal to zero, because InstCombiner always moves

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it to RHS anyway.

llvm-svn: 136586
This commit is contained in:
Jakub Staszak 2011-07-31 04:47:20 +00:00
parent 92b7e5d6e5
commit 6795c54cb7
1 changed files with 8 additions and 24 deletions
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32
lib/Analysis/BranchProbabilityInfo.cpp
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@ -287,21 +287,9 @@ bool BranchProbabilityAnalysis::calcZeroHeuristics(BasicBlock *BB) {
if (!CI) if (!CI)
return false; return false;
Value *LHS = CI->getOperand(0);
Value *RHS = CI->getOperand(1); Value *RHS = CI->getOperand(1);
ConstantInt *CV = dyn_cast<ConstantInt>(RHS);
bool hasZero = false; if (!CV || !CV->isZero())
bool lhsZero = false;
if (ConstantInt *CI = dyn_cast<ConstantInt>(LHS)) {
hasZero = CI->isZero();
lhsZero = true;
}
if (!hasZero)
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS))
hasZero = CI->isZero();
if (!hasZero)
return false; return false;
bool isProb; bool isProb;
@ -321,11 +309,9 @@ bool BranchProbabilityAnalysis::calcZeroHeuristics(BasicBlock *BB) {
case CmpInst::ICMP_SLT: case CmpInst::ICMP_SLT:
case CmpInst::ICMP_SLE: case CmpInst::ICMP_SLE:
// Less or equal to zero is not expected. // Less or equal to zero is not expected.
// 0 < X -> isProb = true // X < 0 -> Unlikely
// 0 <= X -> isProb = true // X <= 0 -> Unlikely
// X < 0 -> isProb = false isProb = false;
// X <= 0 -> isProb = false
isProb = lhsZero;
break; break;
case CmpInst::ICMP_UGT: case CmpInst::ICMP_UGT:
@ -333,11 +319,9 @@ bool BranchProbabilityAnalysis::calcZeroHeuristics(BasicBlock *BB) {
case CmpInst::ICMP_SGT: case CmpInst::ICMP_SGT:
case CmpInst::ICMP_SGE: case CmpInst::ICMP_SGE:
// Greater or equal to zero is expected. // Greater or equal to zero is expected.
// 0 > X -> isProb = false // X > 0 -> Likely
// 0 >= X -> isProb = false // X >= 0 -> Likely
// X > 0 -> isProb = true isProb = true;
// X >= 0 -> isProb = true
isProb = !lhsZero;
break; break;
default: default: