This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] ieee754/dbl-64: Reduce the scope of temporary storage variables


On Mon, 11 Nov 2019, Vineet Gupta wrote:

> Functionally it should not result in code gen changes and if at all
> those would be better since the scope of those temporaries is greatly
> reduced now

This feels like the sort of thing where "should not result in code gen 
changes" should be tested by running build-many-glibcs.py --strip with 
unmodified glibc sources to build a full set of stripped glibc binaries, 
saving those binaries and then running build-many-glibcs.py --strip again 
and comparing the two sets of shared libraries (something I did a lot of 
when reworking how libm function aliases were defined; static libraries 
are expected to change because of timestamps, but shared library binaries 
can be usefully compared like this).  If the two sets of stripped binaries 
are indeed identical, that is strong evidence that the patch is safe; 
otherwise, review of the patch will require more detailed inspection of 
the types of the arguments to these macros, and the uses of the temporary 
variables, at every call site, to make sure that semantics aren't being 
changed.

(In any case, please specify when submitting a patch how it was tested.)

-- 
Joseph S. Myers
joseph@codesourcery.com


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]