[llvm] [InstCombine] Optimize redundant floating point comparisons in `or`/`and` inst's (PR #158097)
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Sun Sep 14 19:21:28 PDT 2025
================
@@ -1850,6 +1850,35 @@ static Value *simplifyAndOrOfFCmps(const SimplifyQuery &Q, FCmpInst *LHS,
: ConstantInt::getBool(LHS->getType(), !IsAnd);
}
+ Value *V0;
+ const APFloat *V0Op1, *V1Op1;
+ // (fcmp olt V0, V0Op1) || (fcmp olt V0, V1Op1)
+ // --> fcmp olt V0, max(V0Op1, V1Op1)
+ // (fcmp ogt V0, V0Op1) || (fcmp ogt V0, V1Op1)
+ // --> fcmp ogt V0, max(V0Op1, V1Op1)
+ //
+ // (fcmp olt V0, V0Op1) && (fcmp olt V0, V1Op1)
+ // --> fcmp olt V0, min(V0Op1, V1Op1)
+ // (fcmp ogt V0, V0Op1) && (fcmp ogt V0, V1Op1)
+ // --> fcmp ogt V0, min(V0Op1, V1Op1)
+ if (match(LHS, m_SpecificFCmp(FCmpInst::FCMP_OLT, m_Value(V0),
+ m_APFloat(V0Op1))) &&
+ match(RHS, m_SpecificFCmp(FCmpInst::FCMP_OLT, m_Specific(V0),
+ m_APFloat(V1Op1)))) {
+ if (*V0Op1 > *V1Op1)
+ return !IsAnd ? LHS : RHS;
----------------
arsenm wrote:
```suggestion
return IsAnd ? RHS : LHS;
```
Same throughout, swap operands and remove negate
https://github.com/llvm/llvm-project/pull/158097
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