[RTEMS Project] #3438: GCC multilibs for ARM don't support FPU synonyms

[RTEMS trac]

#3438: GCC multilibs for ARM don't support FPU synonyms
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  Reporter:  munster   |      Owner:  (none)
      Type:  defect    |     Status:  new
  Priority:  low       |  Milestone:
 Component:  tool/gcc  |    Version:
  Severity:  normal    |   Keywords:  multilibs,GCC,ARM
Blocked By:            |   Blocking:
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 There are two issues with the ARM multilibs.
 1. When a program is compiled with option -mfpu=neon-fp16, the default
 runtime (ARMv4T, no FP) is selected which results of course in linking
 errors.
 2. When there are two object files compiled with different but compatible
 FPU options, the linker fails to understand this.
 Both issues could be fixed with appropriate `MULTILIB_MATCHES` in file
 ''gcc/config/arm/t-rtems''. I have attached the patch with fixes for
 **ARMv7-A** only. It was made by cutting and pasting from ''t-aprofile''.

 I understand that there are many ARM platforms for which this issue
 wouldn't matter, so maybe the better approach would be to have a command
 line argument for GCC's configure script along the lines of
 https://gcc.gnu.org/ml/gcc-patches/2015-11/msg03400.html
 This would allow everybody to select the precise multilibs for the
 platform they have with a minimum hassle.

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Ticket URL: <http://devel.rtems.org/ticket/3438>
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