[PATCH] gas: Add --with-optimization=OPTION

[Jan Beulich]

>>> On 26.02.18 at 19:41, <hjl.tools@gmail.com> wrote:
> On Mon, Feb 26, 2018 at 10:33 AM, Joseph Myers <joseph@codesourcery.com> wrote:
>> On Mon, 26 Feb 2018, H.J. Lu wrote:
>>
>>> 1. Add --with-optimization=OPTION configure option for x86 gas.  This
>>> allows the default optimization type to be adjusted at configure time.
>>
>> I don't think such a configure option is appropriate.  It's far outside
>> the standard definition of either --enable or --with options.
>> Command-line options and assembler directives should be fully sufficient
>> without any such configure option, especially given that the assembler is
> 
> So it is OK to enable encoding optimization by default.  But it is inappropriate
> to control it at configure time.
> 
>> mainly used for assembling compiler output.
>>
> 
> x86 assembler optimizes, immediate. displacement as well as VEX vs EVEX.
> I am intending to enable this by default.   --with-optimization=OPTION provides
> a way to test it for a while.

I don't think optimizations should be enabled by default - that's
simply incompatible with prior versions of gas, and may break
existing code.

Jan