[FFmpeg-devel] [PATCH]Force enable ebp_available for icc

Michael Niedermayer michaelni
Sat Mar 14 01:56:12 CET 2009

On Sat, Mar 14, 2009 at 12:14:09AM +0000, Carl Eugen Hoyos wrote:
> As a workaround, the configure check could be done this way, and it will then
> work with the Intel 11.0 and 11.1 compilers. Interestingly, gcc 3.4.3 always seg
> faults for me on any version (other versions of gcc seem to be ok with the old
> check):
> $ cat ebp.c
> __attribute__((noinline)) void foo() {
> __asm__ volatile (
> "xorl %%ebp, %%ebp"
> ::: "%ebp");
> }
> int main(void){
> volatile int i=0;
> foo();
> return i;
> }
> There is still no guarantee (either on the gcc or the icc side) that this would
> continue to work in the future, but it may not be worth the time for the
> maintainer of FFmpeg to code a check that handles this more precisely.
> [/QUOTE]
> Any comments?
> Is a patch changing the test acceptable?

probably yes

> Am I correct that we are not going to use ebp in main() anyway?

unlikely but not impossible, also variable length arrays might be
used in functions that also use asm with ebp, i wonder if that will
blow up ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Observe your enemies, for they first find out your faults. -- Antisthenes
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