<table border="1" cellspacing="0" cellpadding="8">

    <tr>

        <th>Issue</th>

        <td>

            <a href=https://github.com/llvm/llvm-project/issues/56050>56050</a>

        </td>

    </tr>

    <tr>

        <th>Summary</th>

        <td>

            HexagonExpandCondsets does not preserve LiveIntervals

        </td>

    </tr>

    <tr>

      <th>Labels</th>

      <td>

            backend:Hexagon

      </td>

    </tr>

    <tr>

      <th>Assignees</th>

      <td>

      </td>

    </tr>

    <tr>

      <th>Reporter</th>

      <td>

          jayfoad

      </td>

    </tr>

</table>

<pre>

    See https://reviews.llvm.org/D127731 WIP: [MachineVerifier] Try harder to verify analyses

If I apply just the MachineVerifier part of this patch then I get see a couple of Hexagon CodeGen tests failing with `Bad machine code: Multiple connected components in live interval`:

```

FAIL: LLVM :: CodeGen/Hexagon/expand-condsets-same-inputs.mir (1247 of 1248)

******************** TEST 'LLVM :: CodeGen/Hexagon/expand-condsets-same-inputs.mir' FAILED ********************

Script:

--

: 'RUN: at line 1';   /home/jayfoad2/llvm-release/bin/llc -march=hexagon -run-pass expand-condsets -expand-condsets-coa-limit=0 -o - /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir -verify-machineinstrs | /home/jayfoad2/llvm-release/bin/FileCheck /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir

--

Exit Code: 2

Command Output (stderr):

--

+ : 'RUN: at line 1'

+ /home/jayfoad2/llvm-release/bin/llc -march=hexagon -run-pass expand-condsets -expand-condsets-coa-limit=0 -o - /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir -verify-machineinstrs

+ /home/jayfoad2/llvm-release/bin/FileCheck /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir

# After Hexagon Expand Condsets

********** INTERVALS **********

R0 [0B,0d:0)[96r,96d:1) 0@0B-phi 1@96r

R1 [0B,48r:0) 0@0B-phi

R2 [0B,0d:0) 0@0B-phi

P0~P3_0 [0B,0d:0) 0@0B-phi

%0 [16r,16d:1)[32r,32d:0) 0@32r 1@16r  weight:0.000000e+00

%1 [48r,64r:0) 0@48r  weight:0.000000e+00

%2 [64r,80r:0) 0@64r  weight:0.000000e+00

%3 [80r,96r:0) 0@80r  weight:0.000000e+00

RegMasks:

********** MACHINEINSTRS **********

# Machine code for function fred: NoPHIs, TracksLiveness

0B      bb.0:

          liveins: $r0, $r1, $r2, $p0

16B       dead %0:predregs = COPY $p0

32B       dead %0:predregs = COPY $p0

48B       %1:intregs = COPY $r1

64B       %2:intregs = A2_addi %1:intregs, 1

80B       %3:intregs = COPY killed %2:intregs

96B       $r0 = COPY killed %3:intregs

# End machine code for function fred.

*** Bad machine code: Multiple connected components in live interval ***

- function:    fred

- interval:    %0 [16r,16d:1)[32r,32d:0) 0@32r 1@16r  weight:0.000000e+00

0: valnos 0

1: valnos 1

LLVM ERROR: Found 1 machine code errors.

PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.

Stack dump:

0.      Program arguments: /home/jayfoad2/llvm-release/bin/llc -march=hexagon -run-pass expand-condsets -expand-condsets-coa-limit=0 -o - /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir -verify-machineinstrs

1.      Running pass 'Function Pass Manager' on module '/home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir'.

2.      Running pass 'Verify generated machine code' on function '@fred'

 #0 0x0000000005682ed3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/jayfoad2/llvm-release/bin/llc+0x5682ed3)

 #1 0x0000000005680bfe llvm::sys::RunSignalHandlers() (/home/jayfoad2/llvm-release/bin/llc+0x5680bfe)

 #2 0x000000000568325f SignalHandler(int) Signals.cpp:0:0

 #3 0x00007fa744fd9420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)

 #4 0x00007fa744a6c00b raise /build/glibc-SzIz7B/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1

 #5 0x00007fa744a4b859 abort /build/glibc-SzIz7B/glibc-2.31/stdlib/abort.c:81:7

 #6 0x00000000055e9b63 llvm::report_fatal_error(llvm::Twine const&, bool) (/home/jayfoad2/llvm-release/bin/llc+0x55e9b63)

 #7 0x0000000004a1fdef (/home/jayfoad2/llvm-release/bin/llc+0x4a1fdef)

 #8 0x0000000004959c5e llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/home/jayfoad2/llvm-release/bin/llc+0x4959c5e)

 #9 0x0000000004dd5b38 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/jayfoad2/llvm-release/bin/llc+0x4dd5b38)

#10 0x0000000004ddc378 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/jayfoad2/llvm-release/bin/llc+0x4ddc378)

#11 0x0000000004dd61e7 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/jayfoad2/llvm-release/bin/llc+0x4dd61e7)

#12 0x000000000311d3de main (/home/jayfoad2/llvm-release/bin/llc+0x311d3de)

#13 0x00007fa744a4d083 __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:342:3

#14 0x000000000311a96e _start (/home/jayfoad2/llvm-release/bin/llc+0x311a96e)

FileCheck error: '<stdin>' is empty.

FileCheck command line:  /home/jayfoad2/llvm-release/bin/FileCheck /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-same-inputs.mir

--

********************

FAIL: LLVM :: CodeGen/Hexagon/expand-condsets-def-undef.mir (1248 of 1248)

******************** TEST 'LLVM :: CodeGen/Hexagon/expand-condsets-def-undef.mir' FAILED ********************

Script:

--

: 'RUN: at line 1';   /home/jayfoad2/llvm-release/bin/llc -march=hexagon -run-pass expand-condsets -o - /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-def-undef.mir -verify-machineinstrs | /home/jayfoad2/llvm-release/bin/FileCheck /home/jayfoad2/git/llvm-project/llvm/test/CodeGen/Hexagon/expand-condsets-def-undef.mir

--

Exit Code: 2