Index: llvm/lib/Transforms/Scalar/JumpThreading.cpp =================================================================== --- llvm/lib/Transforms/Scalar/JumpThreading.cpp +++ llvm/lib/Transforms/Scalar/JumpThreading.cpp @@ -452,7 +452,11 @@ << '\n'); LoopHeaders.erase(&BB); LVI->eraseBlock(&BB); - DeleteDeadBlock(&BB, DTU); + // After ProcessBlock, we might generate some unreachable loops, + // thus we need to set the argument KeepOneInputPHIs to be true + // to avoid generating invalid IRs that use not dominated by its + // def in a self-loop. + DeleteDeadBlock(&BB, DTU, true); Changed = true; continue; } Index: llvm/test/Transforms/JumpThreading/keep-one-input-phis.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/JumpThreading/keep-one-input-phis.ll @@ -0,0 +1,80 @@ +; RUN: opt -jump-threading -S < %s | FileCheck %s +@a = common dso_local local_unnamed_addr global i16 0, align 2 + +; Function Attrs: nofree norecurse nounwind +define internal fastcc void @s() unnamed_addr { +; CHECK-LABEL: @s( +; CHECK-NEXT: for.cond1.preheader.lr.ph: +; CHECK-NEXT: br label [[FOR_COND1_PREHEADER:%.*]] +; CHECK: for.cond1.preheader: +; CHECK-NEXT: [[DOTPR_I_19:%.*]] = phi i32 [ undef, [[FOR_COND1_PREHEADER_LR_PH:%.*]] ], [ 0, [[FOR_INC_SPLIT_1:%.*]] ] +; CHECK-NEXT: [[TMP0:%.*]] = phi i16 [ undef, [[FOR_COND1_PREHEADER_LR_PH]] ], [ [[INC9:%.*]], [[FOR_INC_SPLIT_1]] ] +; CHECK-NEXT: [[TOBOOL4_I:%.*]] = icmp eq i32 [[DOTPR_I_19]], 0 +; CHECK-NEXT: br i1 [[TOBOOL4_I]], label [[FOR_INC_SPLIT_1]], label [[FOR_BODY_LR_PH_I:%.*]] +; CHECK: for.body.lr.ph.i: +; CHECK-NEXT: ret void +; CHECK: for.cond.for.end10_crit_edge: +; CHECK-NEXT: ret void +; CHECK: for.inc.split.1: +; CHECK-NEXT: [[INC9]] = add i16 [[TMP0]], 1 +; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i16 [[INC9]], 0 +; CHECK-NEXT: br i1 [[TOBOOL]], label [[FOR_COND_FOR_END10_CRIT_EDGE:%.*]], label [[FOR_COND1_PREHEADER]] +; +for.cond1.preheader.lr.ph: + br label %for.cond1.preheader + +for.cond1.preheader: ; preds = %for.inc.split.1, %for.cond1.preheader.lr.ph + %.pr.i.19 = phi i32 [ undef, %for.cond1.preheader.lr.ph ], [ 0, %for.inc.split.1 ] + %0 = phi i16 [ undef, %for.cond1.preheader.lr.ph ], [ %inc9, %for.inc.split.1 ] + %tobool4.i = icmp eq i32 %.pr.i.19, 0 + br i1 %tobool4.i, label %t.exit, label %for.body.lr.ph.i + +for.body.lr.ph.i: ; preds = %for.cond1.preheader + ret void + +t.exit: ; preds = %for.cond1.preheader + br label %for.inc.split + +for.inc.split: ; preds = %t.exit + %tobool4.i.1 = icmp eq i32 %.pr.i.19, 0 + br i1 %tobool4.i.1, label %for.inc.split.1, label %for.body.lr.ph.i.1 + +for.cond.for.end10_crit_edge: ; preds = %for.inc.split.1 + ret void + +for.body.lr.ph.i.1: ; preds = %for.inc.split + br label %for.body.lr.ph.split.i.1 + +for.body.lr.ph.split.i.1: ; preds = %for.body.lr.ph.i.1 + br label %for.body.preheader.i.1 + +for.body.preheader.i.1: ; preds = %for.body.lr.ph.split.i.1 + br label %for.body.i.us.1.preheader + +for.body.i.us.1.preheader: ; preds = %for.body.preheader.i.1 + br label %for.body.i.us.1 + +for.body.i.us.1: ; preds = %lor.end.i.us.1, %for.body.i.us.1.preheader + %.b.i.us.1 = phi i1 [ %spec.select44.i.us.1, %lor.end.i.us.1 ], [ undef, %for.body.i.us.1.preheader ] + br i1 %.b.i.us.1, label %lor.end.i.us.1, label %lor.rhs.i.us.1 + +lor.rhs.i.us.1: ; preds = %for.body.i.us.1 + %conv5.i.us.1 = trunc i32 undef to i8 + br label %lor.end.i.us.1 + +lor.end.i.us.1: ; preds = %lor.rhs.i.us.1, %for.body.i.us.1 + %.b31.i.us.1 = or i1 undef, %.b.i.us.1 + %spec.select44.i.us.1 = or i1 undef, %.b31.i.us.1 + br i1 undef, label %for.end18.loopexit42.i.1.loopexit, label %for.body.i.us.1 + +for.end18.loopexit42.i.1.loopexit: ; preds = %lor.end.i.us.1 + br label %for.end18.loopexit42.i.1 + +for.end18.loopexit42.i.1: ; preds = %for.end18.loopexit42.i.1.loopexit + br label %for.inc.split.1 + +for.inc.split.1: ; preds = %for.end18.loopexit42.i.1, %for.inc.split + %inc9 = add i16 %0, 1 + %tobool = icmp eq i16 %inc9, 0 + br i1 %tobool, label %for.cond.for.end10_crit_edge, label %for.cond1.preheader +}