[FFmpeg-devel] [PATCH] ff_scalarproduct_float_sse
Wed Jan 20 23:22:12 CET 2010
On Wed, Jan 20, 2010 at 2:20 PM, Uoti Urpala <uoti.urpala at pp1.inet.fi> wrote:
> On Wed, 2010-01-20 at 21:58 +0100, Reimar D?ffinger wrote:
>> On Wed, Jan 20, 2010 at 03:43:23PM -0500, David Conrad wrote:
>> > On Jan 20, 2010, at 9:19 AM, Michael Niedermayer wrote:
>> > > I have no problem with yasm as such but gcc asm is more portable and
>> > > can be integrated with C code if we ever want that.
>> > I'd argue that it's less portable given that the majority of the compiler bugs I've encountered stem from inline asm. In fact, right now llvm svn trips on two separate inline asm bugs on x86-32, and llvm-gcc on another on x86-64. And gcc-4.2 and later have several silent miscompilations and register allocation failure with inline asm on x86-32 OS X when using PIC.
>> Less maintenance effort probably, but not more portable by my definition of it.
> I'm not sure whether yasm can be called less maintenance effort either.
> Were the incorrect section problems in existing FFmpeg yasm parts ever
> completely fixed? Those kinds of things just work automatically in
> inline asm but require highly platform-specific manual work in raw
> assembler like yasm.
That sort of thing is not really a good argument though because it
only has to be done once for all functions, not once for every
function. The costs that matter are the development costs on a
per-function basis; O(1) is meaningless when you have an O(n) cost.
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