On Sun, May 10, 2015 at 6:44 PM, Jan Hubicka <hubi...@ucw.cz> wrote: >> On 32-bit x86, register class CLOBBERED_REGS is a proper subset of >> LEGACY_REGS, which causes IRA not to consider it separately for register >> allocation, even when it has lower cost than other classes. This patch is >> useful to fix code generation problem that appears with no-PLT PIC tailcalls. >> >> Was there a specific reason for CLOBBERED_REGS class to be listed as late as >> it is? On 32-bit this class contains only EAX, ECX, EDX. > > Uros moved CLOBBERED_REGS late in > https://gcc.gnu.org/ml/gcc-patches/2012-08/msg00796.html > which contains a rationale, too. > > I am adding Uros and Vladimir to CC just in case they missed the email :) > Honza
Uh, I don't remember that far, but from the context of the referred patch, it looks like a "cleanup" of some sort. My atch matched 32bit to 64bit, but could be also in the opposite way. Let's try the patch and see what breaks. Uros.
