[FFmpeg-devel] [RFC]Move is-align-a-power-of-two test up

[Reimar Döffinger]

On Sun, Apr 04, 2010 at 10:43:33PM +0000, Carl Eugen Hoyos wrote:
> Reimar D?ffinger <Reimar.Doeffinger <at> gmx.de> writes:
> 
> > On Sat, Apr 03, 2010 at 05:42:43PM +0100, M?ns Rullg?rd wrote:
> > > Carl Eugen Hoyos <cehoyos <at> rainbow.studorg.tuwien.ac.at> writes:
> 
> > > > $ icc align.c -c -ipo
> > > > (succeeds and builds align.o)
> > > > $ icc align.o
> > > > ipo: remark #11001: performing single-file optimizations
> > > > ipo: remark #11005: generating object file /tmp/ipo_iccWkeAyV.o
> > > > /tmp/iccTgD2V5as_.s: Assembler messages:
> > > > /tmp/iccTgD2V5as_.s:13: Error: alignment not a power of 2
> > > > icc: error #10014: problem during multi-file optimization compilation
> > > > (code 1)
> > > 
> > > Do you have any idea why this is so?
> > 
> > My guess: In this mode, icc only generates some intermediate code but no
> > actual object code and does the real optimization, converting to asm
> > and then to object code at the linking stage.
> 
> And without knowing much about compilers, I don't understand how ipo should work
> differently.

It could (and IMO should) generate proper executable data in the .o file and
use the intermediate format only in addition.
Admittedly that would slow down compilation, but the .o files would still be
usable with other compilers and asm errors would be detected much earlier.