rs6000: Ignore OPTION_MASK_SAVE_TOC_INDIRECT differences in inlining decisions [PR119327]

rs6000: Ignore OPTION_MASK_SAVE_TOC_INDIRECT differences in inlining decisions [PR119327]

The following testcase FAILs because the always_inline function can't
be inlined.
The rs6000 backend has similarly to other targets a hook which rejects
inlining which would bring in new ISAs which aren't there in the caller.
And this hook rejects this because of OPTION_MASK_SAVE_TOC_INDIRECT
differences.
This flag is set if explicitly requested or by default depending on
whether the current function looks hot (or at least not cold):
  if ((rs6000_isa_flags_explicit & OPTION_MASK_SAVE_TOC_INDIRECT) == 0
      && flag_shrink_wrap_separate
      && optimize_function_for_speed_p (cfun))
    rs6000_isa_flags |= OPTION_MASK_SAVE_TOC_INDIRECT;
The target nodes that are being compared here are actually the default
target node (which was created when cfun was NULL) vs. one that was
created for the always_inline function when it wasn't NULL, so one
doesn't have it, the other does.
In any case, this flag feels like a tuning decision rather than hard
ISA requirement and I see no problems why we couldn't inline
even explicit -msave-toc-indirect function into -mno-save-toc-indirect
or vice versa.
We already ignore OPTION_MASK_P{8,10}_FUSION which are also more
like tuning flags.

2025-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR target/119327
	* config/rs6000/rs6000.cc (rs6000_can_inline_p): Ignore also
	OPTION_MASK_SAVE_TOC_INDIRECT differences.

	* g++.dg/opt/pr119327.C: New test.