[GHC] #9425: ghc-HEAD (only in -O -fllvm aka 'optllvm') prunes yield in -fno-omit-yields mode

[GHC]

#9425: ghc-HEAD  (only in -O -fllvm aka 'optllvm') prunes yield in -fno-omit-
yields mode
-------------------------------------+-------------------------------------
              Reporter:  slyfox      |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.2
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Description changed by slyfox:

Old description:

> Found on '''./validate --slow''' today:
>
> {{{#!hs
> Unexpected failures:
>    concurrent/should_run  T367_letnoescape [bad exit code] (optllvm)
>
> # run manually:
> $ LANG=C make fulltest stage=2 TEST=T367_letnoescape WAY=optllvm
>
> =====> T367_letnoescape(optllvm) 2419 of 4083 [0, 0, 0]
> cd ./concurrent/should_run && '/home/st/fun/ghc/inplace/bin/ghc-stage2'
> -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-
> db -rtsopts -fno-ghci-history -o T367_letnoescape T367_letnoescape.hs -O
> -fllvm -fno-omit-yields  >T367_letnoescape.comp.stderr 2>&1
> cd ./concurrent/should_run && ./T367_letnoescape    </dev/null
> >T367_letnoescape.run.stdout 2>T367_letnoescape.run.stderr
> Timeout happened...killing process...
> Wrong exit code (expected 0 , actual 99 )
> Stdout:
>
> Stderr:
>
> *** unexpected failure for T367_letnoescape(optllvm)
> }}}
>
> I've loaded test in gdb and manually interrupted it:
> {{{
> ^C
> Program received signal SIGINT, Interrupt.
> 0x0000000000407110 in r5Wp_info ()
> (gdb) disassemble
> Dump of assembler code for function r5Wp_info:
>    0x00000000004070f8 <+0>:     mov    0x358(%r13),%rax
>    0x00000000004070ff <+7>:     dec    %r14
>    0x0000000000407102 <+10>:    data32 data32 data32 data32 nopw
> %cs:0x0(%rax,%rax,1)
>
> => 0x0000000000407110 <+24>:    inc    %r14
>    0x0000000000407113 <+27>:    test   %rax,%rax
>    0x0000000000407116 <+30>:    jne    0x407110 <r5Wp_info+24>
>
>    0x0000000000407118 <+32>:    mov    -0x8(%r13),%rax
>    0x000000000040711c <+36>:    mov    $0x8e0690,%ebx
>    0x0000000000407121 <+41>:    jmpq   *%rax
> End of assembler dump
> }}}
>
> Here we see 3 instructions-long dead loop.
>
> llvm-3.4.2, amd64-linux.
>
> Looks like yield code was not emitted or was moved away.

New description:

 Found on '''./validate --slow''' today:

 {{{
 Unexpected failures:
    concurrent/should_run  T367_letnoescape [bad exit code] (optllvm)

 # run manually:
 $ LANG=C make fulltest stage=2 TEST=T367_letnoescape WAY=optllvm

 =====> T367_letnoescape(optllvm) 2419 of 4083 [0, 0, 0]
 cd ./concurrent/should_run && '/home/st/fun/ghc/inplace/bin/ghc-stage2'
 -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-
 db -rtsopts -fno-ghci-history -o T367_letnoescape T367_letnoescape.hs -O
 -fllvm -fno-omit-yields  >T367_letnoescape.comp.stderr 2>&1
 cd ./concurrent/should_run && ./T367_letnoescape    </dev/null
 >T367_letnoescape.run.stdout 2>T367_letnoescape.run.stderr
 Timeout happened...killing process...
 Wrong exit code (expected 0 , actual 99 )
 Stdout:

 Stderr:

 *** unexpected failure for T367_letnoescape(optllvm)
 }}}

 I've loaded test in gdb and manually interrupted it:
 {{{
 ^C
 Program received signal SIGINT, Interrupt.
 0x0000000000407110 in r5Wp_info ()
 (gdb) disassemble
 Dump of assembler code for function r5Wp_info:
    0x00000000004070f8 <+0>:     mov    0x358(%r13),%rax
    0x00000000004070ff <+7>:     dec    %r14
    0x0000000000407102 <+10>:    data32 data32 data32 data32 nopw
 %cs:0x0(%rax,%rax,1)

 => 0x0000000000407110 <+24>:    inc    %r14
    0x0000000000407113 <+27>:    test   %rax,%rax
    0x0000000000407116 <+30>:    jne    0x407110 <r5Wp_info+24>

    0x0000000000407118 <+32>:    mov    -0x8(%r13),%rax
    0x000000000040711c <+36>:    mov    $0x8e0690,%ebx
    0x0000000000407121 <+41>:    jmpq   *%rax
 End of assembler dump
 }}}

 Here we see 3 instructions-long dead loop.

 llvm-3.4.2, amd64-linux.

 Looks like yield code was not emitted or was moved away.

--

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9425#comment:1>
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