[Bug rtl-optimization/66463] New: review uses of call_used_regs and regs_invalidated_by_call

[Bug rtl-optimization/66463] New: review uses of call_used_regs and regs_invalidated_by_call

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66463

            Bug ID: 66463
           Summary: review uses of call_used_regs and
                    regs_invalidated_by_call
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

With -fipa-ra, we can have a call_used_reg rx that is allocated cross a call.

If we use call_used_regs or regs_invalidated_by_call somewhere during an
optimization after ira, and decide that rx is if fact killed by the call, then
we can get incorrect results. See f.i. PR66444.

We need to review all uses of call_used_regs and regs_invalidated_by_call to
ensure we use the -fipa-ra version if necessary.

F.i., as mentioned in PR66444 comment 2, reload_cse_move2add could use a fix
similar to the one for PR66444.

[Bug rtl-optimization/66463] review uses of call_used_regs and regs_invalidated_by_call

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66463

vries at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vmakarov at redhat dot com

--- Comment #1 from vries at gcc dot gnu.org ---
https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00592.html:
...
Please work out with Vlad whether reload_cse_move2add doesn't need similar
fix (and check other spots too).
...