llvm dev - Dec 2009 - [LLVMdev] detailed comparison of generated code size for LLVM and other compilers

> This might be a very stupid question, but can we not choose to disable
> SSE code generating in a case-by-case basis, even when those
> optimizations are turned on?
>
> In that case, I imagine that 1.0 is considered double and would
> normally fill one or two registers, thus easy enough to return it via
> registers. Unless, of course, the ABI mandates that SSE is
> all-or-nothing...
ABI does not mandate the usage of SSE or x86 FP math exclusively.
It just requires the FP values to be *always* returned via FP stack.

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

2009/12/15 Anton Korobeynikov <anton at
korobeynikov.info>:
> ABI does not mandate the usage of SSE or x86 FP math exclusively.
> It just requires the FP values to be *always* returned via FP stack.
Makes sense, probably avoiding duplicating hardware logic.

cheers,
--renato

http://systemcall.org/

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> Makes sense, probably avoiding duplicating hardware logic.
No. Surely not to break legacy code :)

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University