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Message #08981
Re: gcc 4.7.x and optimization flags
On 10/16/2012 01:17 PM, Wayne Stambaugh wrote:
> On 10/16/2012 1:31 AM, Dick Hollenbeck wrote:
>> On 10/15/2012 08:49 PM, Wayne Stambaugh wrote:
>>> Dick,
>>>
>>> I just committed a fix so that the only time -O1 is only used when the
>>> GCC version is >= 4.7. When you get a chance, please test it out to
>>> make sure it works with GCC versions < 4.7. Both my Linux and Windows
>>> build environments are using GCC >= 4.7. I suppose I could install an
>>> older version of GCC on Linux when I get chance.
>>>
>>> Wayne
>>
>> Thanks for doing that. Someday we might take it even further and compile on those certain
>> needed files under 4.7.x that must be done with -O1, others with -O2.
>>
>> This is easier than it sounds since gcc will ignore all but the right most optimization
>> setting on the command line.
>>
>> So really, you just have to set set_source_file_properties() on a few files and pass in
>> the -O1 as COMPILE_FLAGS or such (don't hold me on spelling), and as long as CMake appends
>> that to other stuff, then -O1 will prevail on only those files.
>
> Sounds reasonable. It would only apply to the source files that include
> the Boost polygon library. JP would have a better idea about which
> source files would need to be compiled with -O1. Since my
> -Wno-narrowing fix also applies to the Boost polygon library we could
> throw that in there as well. If JP doesn't have time, I'll take a look
> at it when I get a chance.
>
> Wayne
>From another project I am using CMake, this might work:
set_source_files_properties( file1.cpp file2.cpp ...
PROPERTIES
COMPILE_FLAGS "-O1"
)
Wrap that in "if test" condition of "GCC and 4.7"
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