diff options
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 39 | ||||
| -rw-r--r-- | llvm/test/Transforms/IndVarSimplify/bec-cmp.ll | 47 |
2 files changed, 85 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 7cf08bd7156..363731a0b6c 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -7326,6 +7326,42 @@ static bool IsMinConsistingOf(ScalarEvolution &SE, return IsMaxConsistingOf<MaxExprType>(MaybeMaxExpr, SE.getNotSCEV(Candidate)); } +static bool IsKnownPredicateViaAddRecStart(ScalarEvolution &SE, + ICmpInst::Predicate Pred, + const SCEV *LHS, const SCEV *RHS) { + + // If both sides are affine addrecs for the same loop, with equal + // steps, and we know the recurrences don't wrap, then we only + // need to check the predicate on the starting values. + + if (!ICmpInst::isRelational(Pred)) + return false; + + const SCEVAddRecExpr *LAR = dyn_cast<SCEVAddRecExpr>(LHS); + if (!LAR) + return false; + const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS); + if (!RAR) + return false; + if (LAR->getLoop() != RAR->getLoop()) + return false; + if (!LAR->isAffine() || !RAR->isAffine()) + return false; + + if (LAR->getStepRecurrence(SE) != RAR->getStepRecurrence(SE)) + return false; + + auto CheckWrap = [Pred](const SCEVAddRecExpr *AR) -> bool { + if (ICmpInst::isSigned(Pred)) + return AR->getNoWrapFlags(SCEV::FlagNSW); + return AR->getNoWrapFlags(SCEV::FlagNUW); + }; + + if (!CheckWrap(LAR) || !CheckWrap(RAR)) + return false; + + return SE.isKnownPredicate(Pred, LAR->getStart(), RAR->getStart()); +} /// Is LHS `Pred` RHS true on the virtue of LHS or RHS being a Min or Max /// expression? @@ -7371,7 +7407,8 @@ ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred, auto IsKnownPredicateFull = [this](ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS) { return isKnownPredicateWithRanges(Pred, LHS, RHS) || - IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS); + IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) || + IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS); }; switch (Pred) { diff --git a/llvm/test/Transforms/IndVarSimplify/bec-cmp.ll b/llvm/test/Transforms/IndVarSimplify/bec-cmp.ll new file mode 100644 index 00000000000..06a7d5ebe4d --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/bec-cmp.ll @@ -0,0 +1,47 @@ +; RUN: opt -S -indvars < %s | FileCheck %s +target datalayout = "E-m:e-i64:64-n32:64" +target triple = "powerpc64-unknown-linux-gnu" + +; Function Attrs: nounwind +define void @foo(i32* nocapture %a, i32* nocapture readonly %b, i32 signext %n) #0 { +entry: + +; CHECK-LABEL: @foo + + %cmp.10 = icmp sgt i32 %n, 0 + br i1 %cmp.10, label %for.body.lr.ph, label %for.cond.cleanup + +for.body.lr.ph: ; preds = %entry + br label %for.body + +for.cond.for.cond.cleanup_crit_edge: ; preds = %for.inc + br label %for.cond.cleanup + +for.cond.cleanup: ; preds = %for.cond.for.cond.cleanup_crit_edge, %entry + ret void + +for.body: ; preds = %for.body.lr.ph, %for.inc + %i.011 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ] + %cmp1 = icmp sgt i32 %i.011, %n + br i1 %cmp1, label %if.then, label %for.inc + +; CHECK-NOT: br i1 %cmp1, label %if.then, label %for.inc +; CHECK: br i1 false, label %if.then, label %for.inc + +if.then: ; preds = %for.body + %idxprom = sext i32 %i.011 to i64 + %arrayidx = getelementptr inbounds i32, i32* %b, i64 %idxprom + %0 = load i32, i32* %arrayidx, align 4 + %add = add nsw i32 %0, 1 + %arrayidx3 = getelementptr inbounds i32, i32* %a, i64 %idxprom + store i32 %add, i32* %arrayidx3, align 4 + br label %for.inc + +for.inc: ; preds = %for.body, %if.then + %inc = add nsw i32 %i.011, 1 + %cmp = icmp slt i32 %inc, %n + br i1 %cmp, label %for.body, label %for.cond.for.cond.cleanup_crit_edge +} + +attributes #0 = { nounwind } + |
