[Bug target/67591] New: ARM v8 Thumb IT blocks deprecated

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67591

            Bug ID: 67591
           Summary: ARM v8 Thumb IT blocks deprecated
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: clyon at gcc dot gnu.org
  Target Milestone: ---
            Target: ARM

Conditional compare patterns in the arm backend have not been adjusted for the
-mrestrict-it rules, which leads to gas warning messages such as:

IT blocks containing 32-bit Thumb instructions are deprecated in ARMv8.

For instance, it happens in
libstdc++/testsuite/21_strings/basic_string/allocator/char/minimal.cc
when GCC is configured:
--target arm-none-linux-gnueabihf
--with-mode thumb
--with-cpu cortex-a57
--with-fpu crypto-neon-fp-armv8