[Bug target/113357] [14 regression] m68k-linux bootstrap failure in stage2 due to segfault compiling unwind-dw2.c since r14-4664-g04c9cf5c786b94

[law at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113357

Jeffrey A. Law  changed:

   What|Removed |Added

   Priority|P3  |P4

--- Comment #5 from Jeffrey A. Law  ---
So given my bootstraps (qemu) are working the most likely scenarios are either
a difference in the emulators or a difference in the configure setup.

The first thing I would suggest would be to put the stage2 compiler under a
debugger and find out why it faulted.  That might help with understanding the
problem.  ie, are we segfaulting because we dereferenced a NULL pointer, or
perhaps faulting because we did an unaligned access, or whatever.

The next thing I would suggest would be extracting the .i file and confirming
you  can feed that to the stage2 cc1 and see the fault.  Assuming you can, then
you ought to be able to do an object bisection.  ie, replace .o files for the
failing stage with those from a previous stage, relink, retest.  It'll take a
while.  But  this usually results in finding a single trigger file.  Once
that's narrowed down we can figure out the next steps.

[Bug target/113357] [14 regression] m68k-linux bootstrap failure in stage2 due to segfault compiling unwind-dw2.c

[mikpelinux at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113357

--- Comment #4 from Mikael Pettersson  ---
Confirmed:

04c9cf5c786b94fbe3f6f21f06cae73a7575ff7a is the first new commit
commit 04c9cf5c786b94fbe3f6f21f06cae73a7575ff7a
Author: Manolis Tsamis 
Date:   Mon Oct 16 13:08:12 2023 -0600

Implement new RTL optimizations pass: fold-mem-offsets

[Bug target/113357] [14 regression] m68k-linux bootstrap failure in stage2 due to segfault compiling unwind-dw2.c

[mikpelinux at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113357

--- Comment #3 from Mikael Pettersson  ---
git bisect identified the following as the start of this error:

# new: [04c9cf5c786b94fbe3f6f21f06cae73a7575ff7a] Implement new RTL
optimizations pass: fold-mem-offsets

Note the error still reproduced as of 2024-01-07 so wasn't fixed by PR111601.

(Technically my bisect has one more commit to test, the one immediately before
the above, but that one only updates gcc/d/ so cannot have any impact to my
bootstraps.)

[Bug target/113357] [14 regression] m68k-linux bootstrap failure in stage2 due to segfault compiling unwind-dw2.c

[mikpelinux at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113357

--- Comment #2 from Mikael Pettersson  ---
/mnt/scratch/gcc-14-20240107/configure --prefix=/mnt/scratch/install14
--enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-gnu-unique-object
--enable-linker-build-id --with-linker-hash-style=gnu --disable-sjlj-exceptions
--disable-plugin --disable-lto --disable-multilib --disable-libgomp
--enable-initfini-array --enable-languages=c,c++

[Bug target/113357] [14 regression] m68k-linux bootstrap failure in stage2 due to segfault compiling unwind-dw2.c

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113357

Andrew Pinski  changed:

   What|Removed |Added

   Host||m68k-linux-gnu
  Component|bootstrap   |target
   Target Milestone|--- |14.0
 Target||m68k-linux-gnu
  Build||m68k-linux-gnu
   Keywords||build, ice-on-valid-code,
   ||wrong-code

--- Comment #1 from Andrew Pinski  ---
Can you provide the exact configure options so someone might be able to
reproduce it too?