strange move of __asm__

[Jeffrey A Law]

  In message < 199903181452.PAA01522@jet.franken.de >you write:
  > (WINAPI is a #define for __attribute__((__stdcall__)), TEB is a struct)
  > 
  > It compiles to the following (correct working) assemblercode on i386 on
  > "gcc version egcs-2.93.12 19990314 (gcc2 ss-980929 experimental)":
  > 
  > 000000fc <NtCurrentTeb>:
  >   fc:   b8 18 00 00 00  movl   $0x18,%eax
  >  101:   64 8b 00        movl   %fs:(%eax),%eax
  >  104:   55              pushl  %ebp
  >  105:   89 e5           movl   %esp,%ebp
  >  107:   89 ec           movl   %ebp,%esp
  >  109:   5d              popl   %ebp
  >  10a:   c3              ret    
  > 
  > egcs has moved the __asm__ outside the stackframe enter/leave. Now,
  > should this happen?
There's nothing which prevents it -- movement of instructions is constrained
by data dependency.  There are no data dependencies between the asm and the
prologue/epilogue code, so there's nothing to prevent the movement of the
asm.

  > And couldn't egcs optimize the framestuff away if nothing is inside it?
If you compile with -fomit-frame-pointer it probably will.

jeff