i386 - subtle bug with asm volatile constraints

Jeffrey A Law law@upchuck.cygnus.com
Fri Apr 9 00:37:00 GMT 1999

  In message <XFMail.990401091916.markus.oberhumer@jk.uni-linz.ac.at>you write:
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  > I originally had sent this report to the linux-kernel mailing list
  > because I suspected a problem with some asm volatile statement,
  > but it looks like this is indeed a gcc bug.
  > The bug as triggered by the test program attached below can
  > be reproduced at least with gcc 2.7.2, egcs 1.1.1 and egcs 1.1.2.
  > The result of this bug is the generation of wrong code.
I tried your test program and it did not exhibit the behavior you suggested
(missing int $0x80) when defining EAX to "0".

I think you need to do some more investigation into the bug, possibly
providing either a new testcase or enough analysis of the problem so that
we can identify precisely what part of the compiler is broken and correct it.


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