diff options
| -rw-r--r-- | lib/Analysis/ScalarEvolutionExpander.cpp | 12 | ||||
| -rw-r--r-- | test/Transforms/LoopStrengthReduce/X86/2012-01-13-phielim.ll | 50 |
2 files changed, 61 insertions, 1 deletions
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index 8dc8eb68ff..e2f75aa0ea 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -1541,6 +1541,13 @@ SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L, /// general code-insertion helper. bool SCEVExpander::hoistStep(Instruction *IncV, Instruction *InsertPos, const DominatorTree *DT) { + // Phi nodes are strangely positional but don't follow normal rules for + // instruction dominance. Handle them immediately. + if (isa<PHINode>(InsertPos)) + return isa<PHINode>(IncV); + else if (isa<PHINode>(IncV)) + return false; + if (DT->dominates(IncV, InsertPos)) return true; @@ -1648,7 +1655,10 @@ unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT, << *IsomorphicInc << '\n'); Value *NewInc = OrigInc; if (OrigInc->getType() != IsomorphicInc->getType()) { - IRBuilder<> Builder(OrigInc->getNextNode()); + Instruction *IP = isa<PHINode>(OrigInc) + ? (Instruction*)L->getHeader()->getFirstInsertionPt() + : OrigInc->getNextNode(); + IRBuilder<> Builder(IP); Builder.SetCurrentDebugLocation(IsomorphicInc->getDebugLoc()); NewInc = Builder. CreateTruncOrBitCast(OrigInc, IsomorphicInc->getType(), IVName); diff --git a/test/Transforms/LoopStrengthReduce/X86/2012-01-13-phielim.ll b/test/Transforms/LoopStrengthReduce/X86/2012-01-13-phielim.ll new file mode 100644 index 0000000000..08e35de082 --- /dev/null +++ b/test/Transforms/LoopStrengthReduce/X86/2012-01-13-phielim.ll @@ -0,0 +1,50 @@ +; RUN: llc < %s -O3 -march=x86-64 -mcpu=core2 | FileCheck %s + +declare i1 @check() nounwind +declare i1 @foo(i8*, i8*, i8*) nounwind + +; Check that redundant phi elimination ran +; CHECK: @test +; CHECK: %while.body.i +; CHECK: movs +; CHECK-NOT: movs +; CHECK: %for.end.i +define i32 @test(i8* %base) nounwind uwtable ssp { +entry: + br label %while.body.lr.ph.i + +while.body.lr.ph.i: ; preds = %cond.true.i + br label %while.body.i + +while.body.i: ; preds = %cond.true29.i, %while.body.lr.ph.i + %indvars.iv7.i = phi i64 [ 16, %while.body.lr.ph.i ], [ %indvars.iv.next8.i, %cond.true29.i ] + %i.05.i = phi i64 [ 0, %while.body.lr.ph.i ], [ %indvars.iv7.i, %cond.true29.i ] + %sext.i = shl i64 %i.05.i, 32 + %idx.ext.i = ashr exact i64 %sext.i, 32 + %add.ptr.sum.i = add i64 %idx.ext.i, 16 + br label %for.body.i + +for.body.i: ; preds = %for.body.i, %while.body.i + %indvars.iv.i = phi i64 [ 0, %while.body.i ], [ %indvars.iv.next.i, %for.body.i ] + %add.ptr.sum = add i64 %add.ptr.sum.i, %indvars.iv.i + %arrayidx22.i = getelementptr inbounds i8* %base, i64 %add.ptr.sum + %0 = load i8* %arrayidx22.i, align 1 + %indvars.iv.next.i = add i64 %indvars.iv.i, 1 + %cmp = call i1 @check() nounwind + br i1 %cmp, label %for.end.i, label %for.body.i + +for.end.i: ; preds = %for.body.i + %add.ptr.i144 = getelementptr inbounds i8* %base, i64 %add.ptr.sum.i + %cmp2 = tail call i1 @foo(i8* %add.ptr.i144, i8* %add.ptr.i144, i8* undef) nounwind + br i1 %cmp2, label %cond.true29.i, label %cond.false35.i + +cond.true29.i: ; preds = %for.end.i + %indvars.iv.next8.i = add i64 %indvars.iv7.i, 16 + br i1 false, label %exit, label %while.body.i + +cond.false35.i: ; preds = %for.end.i + unreachable + +exit: ; preds = %cond.true29.i, %cond.true.i + ret i32 0 +} |