[RTEMS Project] #3943: i386: unknown register name 'fpcr' in 'asm'

[RTEMS trac]

#3943: i386: unknown register name 'fpcr' in 'asm'
-----------------------------+-------------------------
 Reporter:  Sebastian Huber  |       Owner:  (none)
     Type:  defect           |      Status:  new
 Priority:  normal           |   Milestone:  Indefinite
Component:  arch/i386        |     Version:
 Severity:  normal           |  Resolution:
 Keywords:                   |  Blocked By:
 Blocking:                   |
-----------------------------+-------------------------

Comment (by Joel Sherrill):

 I posted to GCC's mailing list but don't have a GCC 10 compiler to test
 this with.
 Uros Bizjak gave this advice
 (https://gcc.gnu.org/pipermail/gcc/2020-April/232143.html):


 {{{
 Just remove the fpcr clobber. FP control register was never properly
 handled.

 Please also note gcc manual section "6.47.2.1 Volatile", where the
 manual discusses similar case of a system register that controls the
 rounding mode of floating-point operations. You have to add an
 artificial dependency to the asm by referencing a variable in the
 subsequent code, otherwise the compiler may move the access to system
 register across the arithmetic insn.
 }}}

 Can you try this Sebastian? Thanks.

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Ticket URL: <http://devel.rtems.org/ticket/3943#comment:2>
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