[Bug target/54232] For x86 PIC code, ebx should be spillable

[bugdal at aerifal dot cx]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54232

--- Comment #1 from Rich Felker <bugdal at aerifal dot cx> 2012-08-12 04:57:07 UTC ---
By the way, the code that inspired this report is crypt_blowfish.c and the
corresponding asm by Solar Designer. We've been experimenting with performance
characteristics while integrating it into musl libc, and I found that the C
code is just as fast as the hand-optimized asm on the machine I was testing it
on when using static libraries without -fPIC, but takes over 30% more runtime
when built with -fPIC due to running out of registers.