Index: lib/CodeGen/MachinePipeliner.cpp =================================================================== --- lib/CodeGen/MachinePipeliner.cpp +++ lib/CodeGen/MachinePipeliner.cpp @@ -2648,8 +2648,7 @@ // references another Phi, and the other Phi is scheduled in an // earlier stage. We can try to reuse an existing Phi up until the last // stage of the current Phi. - if (LoopDefIsPhi && VRMap[CurStageNum].count(LoopVal) && - LoopValStage >= (int)(CurStageNum - LastStageNum)) { + if (LoopDefIsPhi && (int)PrologStage >= StageScheduled) { int LVNumStages = Schedule.getStagesForPhi(LoopVal); int StageDiff = (StageScheduled - LoopValStage); LVNumStages -= StageDiff; Index: test/CodeGen/Hexagon/swp-epilog-reuse-1.ll =================================================================== --- /dev/null +++ test/CodeGen/Hexagon/swp-epilog-reuse-1.ll @@ -0,0 +1,44 @@ +; RUN: llc -march=hexagon -mcpu=hexagonv60 < %s +; REQUIRES: asserts + +; Test that the pipeliner reuses an existing Phi when generating the epilog +; block. In this case, the original loops has a Phi whose operand is another +; Phi. When the loop is pipelined, the Phi that generates the operand value +; is used in two stages. This means the the Phi for the second stage can +; be reused. The bug causes an assert due to an invalid virtual register error +; in the live variable analysis. + +define void @test(i8* %a, i8* %b) #0 { +entry: + br label %for.body6.us.prol + +for.body6.us.prol: + %i.065.us.prol = phi i32 [ 0, %entry ], [ %inc.us.prol, %for.body6.us.prol ] + %im1.064.us.prol = phi i32 [ undef, %entry ], [ %i.065.us.prol, %for.body6.us.prol ] + %prol.iter = phi i32 [ undef, %entry ], [ %prol.iter.sub, %for.body6.us.prol ] + %arrayidx8.us.prol = getelementptr inbounds i8, i8* %b, i32 %im1.064.us.prol + %0 = load i8, i8* %arrayidx8.us.prol, align 1 + %conv9.us.prol = sext i8 %0 to i32 + %add.us.prol = add nsw i32 %conv9.us.prol, 0 + %add12.us.prol = add nsw i32 %add.us.prol, 0 + %mul.us.prol = mul nsw i32 %add12.us.prol, 3 + %conv13.us.prol = trunc i32 %mul.us.prol to i8 + %arrayidx14.us.prol = getelementptr inbounds i8, i8* %a, i32 %i.065.us.prol + store i8 %conv13.us.prol, i8* %arrayidx14.us.prol, align 1 + %inc.us.prol = add nuw nsw i32 %i.065.us.prol, 1 + %prol.iter.sub = add i32 %prol.iter, -1 + %prol.iter.cmp = icmp eq i32 %prol.iter.sub, 0 + br i1 %prol.iter.cmp, label %for.body6.us, label %for.body6.us.prol + +for.body6.us: + %im2.063.us = phi i32 [ undef, %for.body6.us ], [ %im1.064.us.prol, %for.body6.us.prol ] + %arrayidx10.us = getelementptr inbounds i8, i8* %b, i32 %im2.063.us + %1 = load i8, i8* %arrayidx10.us, align 1 + %conv11.us = sext i8 %1 to i32 + %add12.us = add nsw i32 0, %conv11.us + %mul.us = mul nsw i32 %add12.us, 3 + %conv13.us = trunc i32 %mul.us to i8 + store i8 %conv13.us, i8* undef, align 1 + br label %for.body6.us +} +