[clang] [llvm] [SimplifyCFG] Merge compatible noreturn calls terminating in unreachable (PR #214799)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 180572 tests passed
* 3679 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.Transforms/PhaseOrdering/dae-dce.ll</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -S -passes="default<O3>" < /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/dae-dce.ll | /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/dae-dce.ll --check-prefixes=CHECK,DEFAULT
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -S '-passes=default<O3>'
# note: command had no output on stdout or stderr
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/dae-dce.ll --check-prefixes=CHECK,DEFAULT
# .---command stderr------------
# | /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/dae-dce.ll:37:15: error: CHECK-NEXT: is not on the line after the previous match
# | ; CHECK-NEXT: tail call fastcc void @capture_and_trap()
# |               ^
# | <stdin>:22:2: note: 'next' match was here
# |  tail call fastcc void @capture_and_trap()
# |  ^
# | <stdin>:20:19: note: previous match ended here
# | define void @test(i1 %c) local_unnamed_addr #0 {
# |                   ^
# | <stdin>:21:1: note: non-matching line after previous match is here
# | unreachable.merge:
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/dae-dce.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            .
# |            .
# |            .
# |           15:  tail call void @llvm.trap() 
# |           16:  unreachable 
# |           17: } 
# |           18:  
# |           19: ; Function Attrs: cold noreturn nounwind memory(inaccessiblemem: write) 
# |           20: define void @test(i1 %c) local_unnamed_addr #0 { 
# | next:37'0                      {                                 search range start (exclusive)
# |           21: unreachable.merge: 
# |           22:  tail call fastcc void @capture_and_trap() 
# | next:37'1      !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   error: match on wrong line
# |           23:  unreachable 
# |           24: } 
# |           25:  
# |           26: attributes #0 = { cold noreturn nounwind memory(inaccessiblemem: write) } 
# |           27: attributes #1 = { cold noinline noreturn nounwind memory(inaccessiblemem: write) } 
# | next:37'2                                                                                        } search range end (exclusive)
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/214799