1; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx908 -verify-machineinstrs -stop-after=amdgpu-isel -o - %s | FileCheck -check-prefix=GCN %s
2define void @test() #1 {
3  ; Clean up the unreachable blocks introduced with LowerSwitch pass.
4  ; This test ensures that, in the pass flow, UnreachableBlockElim pass
5  ; follows the LowerSwitch. Otherwise, this testcase will crash
6  ; immediately after the instruction selection due to the incomplete
7  ; PHI node in an MBB whose incoming values were never codegenerated.
8  ;
9  ; GCN-LABEL: name: test
10  ; GCN: bb.{{[0-9]+}}.entry:
11  ; GCN: bb.{{[0-9]+}}.entry.true.blk:
12  ; GCN: bb.{{[0-9]+}}.entry.false.blk:
13  ; GCN: bb.{{[0-9]+}}.switch.blk:
14
15  ; GCN-NOT: bb.{{[0-9]+}}.preheader.blk
16  ; GCN-NOT: bb.{{[0-9]+}}.pre.false.blk:
17  ; GCN-NOT: bb.{{[0-9]+}}.unreach.blk:
18  ; GCN-NOT: PHI
19
20  ; GCN: bb.{{[0-9]+}}.exit:
21  entry:
22    %idx = tail call i32 @llvm.amdgcn.workitem.id.x() #0
23    br i1 undef, label %entry.true.blk, label %entry.false.blk
24
25  entry.true.blk:                                   ; preds = %entry
26    %exit.cmp = icmp ult i32 %idx, 3
27    br i1 %exit.cmp, label %switch.blk, label %exit
28
29  entry.false.blk:                                  ; preds = %entry
30    unreachable
31
32  switch.blk:                                       ; preds = %entry.true.blk
33    switch i32 %idx, label %preheader.blk [
34      i32 0, label %exit
35      i32 1, label %exit
36      i32 2, label %exit
37    ]
38
39  preheader.blk:                                    ; preds = %switch.blk
40    %pre.exit = icmp ult i32 %idx, 5
41    br i1 %pre.exit, label %unreach.blk, label %pre.false.blk
42
43  pre.false.blk:                                    ; preds = %preheader.blk
44    %call.pre.false = tail call i32 @func(i32 %idx) #0
45    br label %unreach.blk
46
47  unreach.blk:                                      ; preds = %preheader.blk, %pre.false.blk
48    %phi.val = phi i32 [ %call.pre.false, %pre.false.blk ], [ undef, %preheader.blk ]
49    store i32 %phi.val, i32* undef
50    unreachable
51
52  exit:                                             ; preds = %switch.blk
53    ret void
54}
55
56declare i32 @llvm.amdgcn.workitem.id.x() #0
57declare i32 @func(i32)#0
58
59attributes #0 = { nounwind readnone }
60attributes #1 = { nounwind }
61