On Fri, Jul 27, 2018 at 4:03 PM, James Darnley <jdarn...@obe.tv> wrote: > On 2018-07-27 15:05, Henrik Gramner wrote: >> Can't you just use 7 GPR:s on x86-32 as well? > > I'm sure I've done that in the past and at least 1 platform has always > complained due to PIE or stack alignment or whatever, I think. I went > looking for an old email but couldn't find it. > > If you want me to try it I can.
If you're allocating stack space with a positive number there has to be a register available to store the old stack pointer in case the guaranteed stack alignment is smaller than the required stack alignment. This can be avoided by using a negative value for the stack space in case of high register pressure which will allocate space for the old stack pointer and store it on the stack after allocation/alignment. In functions that doesn't use the stack this is a non-issue. So it should be fine to use 7 registers here. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
