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llvm-mirror/test/Transforms/JumpThreading/unreachable-loops.ll
Sanjay Patel 06d5ff1803 [JumpThreading][VectorUtils] avoid infinite loop on unreachable IR
https://llvm.org/PR48362

It's possible that we could stub this out sooner somewhere
within JumpThreading, but I'm not sure how to do that, and
then we would still have potential danger in other callers.

I can't find a way to trigger this using 'instsimplify',
however, because that already has a bailout on unreachable
blocks.
2020-12-02 13:39:33 -05:00

146 lines
5.2 KiB
LLVM

; RUN: opt -jump-threading -S < %s | FileCheck %s
; RUN: opt -passes=jump-threading -S < %s | FileCheck %s
; Check the unreachable loop won't cause infinite loop
; in jump-threading when it tries to update the predecessors'
; profile metadata from a phi node.
define void @unreachable_single_bb_loop() {
; CHECK-LABEL: @unreachable_single_bb_loop(
bb:
%tmp = call i32 @a()
%tmp1 = icmp eq i32 %tmp, 1
br i1 %tmp1, label %bb5, label %bb8
; unreachable single bb loop.
bb2: ; preds = %bb2
%tmp4 = icmp ne i32 %tmp, 1
switch i1 %tmp4, label %bb2 [
i1 0, label %bb5
i1 1, label %bb8
]
bb5: ; preds = %bb2, %bb
%tmp6 = phi i1 [ %tmp1, %bb ], [ false, %bb2 ]
br i1 %tmp6, label %bb8, label %bb7, !prof !0
bb7: ; preds = %bb5
br label %bb8
bb8: ; preds = %bb8, %bb7, %bb5, %bb2
ret void
}
define void @unreachable_multi_bbs_loop() {
; CHECK-LABEL: @unreachable_multi_bbs_loop(
bb:
%tmp = call i32 @a()
%tmp1 = icmp eq i32 %tmp, 1
br i1 %tmp1, label %bb5, label %bb8
; unreachable two bbs loop.
bb3: ; preds = %bb2
br label %bb2
bb2: ; preds = %bb3
%tmp4 = icmp ne i32 %tmp, 1
switch i1 %tmp4, label %bb3 [
i1 0, label %bb5
i1 1, label %bb8
]
bb5: ; preds = %bb2, %bb
%tmp6 = phi i1 [ %tmp1, %bb ], [ false, %bb2 ]
br i1 %tmp6, label %bb8, label %bb7, !prof !0
bb7: ; preds = %bb5
br label %bb8
bb8: ; preds = %bb8, %bb7, %bb5, %bb2
ret void
}
declare i32 @a()
; This gets into a state that could cause instruction simplify
; to hang - an insertelement instruction has itself as an operand.
define void @PR48362() {
; CHECK-LABEL: @PR48362(
cleanup1491: ; preds = %for.body1140
switch i32 0, label %cleanup2343.loopexit4 [
i32 0, label %cleanup.cont1500
i32 128, label %lbl_555.loopexit
]
cleanup.cont1500: ; preds = %cleanup1491
unreachable
lbl_555.loopexit: ; preds = %cleanup1491
br label %for.body1509
for.body1509: ; preds = %for.inc2340, %lbl_555.loopexit
%l_580.sroa.0.0 = phi <4 x i32> [ <i32 1684658741, i32 1684658741, i32 1684658741, i32 1684658741>, %lbl_555.loopexit ], [ %l_580.sroa.0.2, %for.inc2340 ]
%p_55.addr.10 = phi i16 [ 0, %lbl_555.loopexit ], [ %p_55.addr.11, %for.inc2340 ]
%i82 = load i32, i32* undef, align 1
%tobool1731.not = icmp eq i32 %i82, 0
br i1 %tobool1731.not, label %if.end1733, label %if.then1732
if.then1732: ; preds = %for.body1509
br label %cleanup2329
if.end1733: ; preds = %for.body1509
%tobool1735.not = icmp eq i16 %p_55.addr.10, 0
br i1 %tobool1735.not, label %if.then1736, label %if.else1904
if.then1736: ; preds = %if.end1733
br label %cleanup2329
if.else1904: ; preds = %if.end1733
br label %for.body1911
for.body1911: ; preds = %if.else1904
%l_580.sroa.0.4.vec.extract683 = extractelement <4 x i32> %l_580.sroa.0.0, i32 2
%xor2107 = xor i32 undef, %l_580.sroa.0.4.vec.extract683
br label %land.end2173
land.end2173: ; preds = %for.body1911
br i1 undef, label %if.end2178, label %cleanup2297
if.end2178: ; preds = %land.end2173
%l_580.sroa.0.2.vec.insert = insertelement <4 x i32> %l_580.sroa.0.0, i32 undef, i32 1
br label %cleanup2297
cleanup2297: ; preds = %if.end2178, %land.end2173
%l_580.sroa.0.1 = phi <4 x i32> [ %l_580.sroa.0.2.vec.insert, %if.end2178 ], [ %l_580.sroa.0.0, %land.end2173 ]
br label %cleanup2329
cleanup2329: ; preds = %cleanup2297, %if.then1736, %if.then1732
%l_580.sroa.0.2 = phi <4 x i32> [ %l_580.sroa.0.0, %if.then1736 ], [ %l_580.sroa.0.1, %cleanup2297 ], [ %l_580.sroa.0.0, %if.then1732 ]
%cleanup.dest.slot.11 = phi i32 [ 0, %if.then1736 ], [ undef, %cleanup2297 ], [ 129, %if.then1732 ]
%p_55.addr.11 = phi i16 [ %p_55.addr.10, %if.then1736 ], [ undef, %cleanup2297 ], [ %p_55.addr.10, %if.then1732 ]
switch i32 %cleanup.dest.slot.11, label %cleanup2343.loopexit [
i32 0, label %cleanup.cont2339
i32 129, label %crit_edge114
]
cleanup.cont2339: ; preds = %cleanup2329
br label %for.inc2340
for.inc2340: ; preds = %cleanup.cont2339
br i1 undef, label %for.body1509, label %crit_edge115
crit_edge114: ; preds = %cleanup2329
unreachable
crit_edge115: ; preds = %for.inc2340
unreachable
cleanup2343.loopexit: ; preds = %cleanup2329
unreachable
cleanup2343.loopexit4: ; preds = %cleanup1491
unreachable
}
!0 = !{!"branch_weights", i32 2146410443, i32 1073205}