Opened 5 years ago
Closed 5 years ago
#4629 closed enhancement (fixed)
Remove NUMERICFLAGS
Reported by: | Algunenano | Owned by: | Algunenano |
---|---|---|---|
Priority: | medium | Milestone: | PostGIS 3.1.0 |
Component: | postgis | Version: | master |
Keywords: | Cc: |
Description
While looking at other flags, I noticed the existence of NUMERICFLAGS
which activates -ffloat-store
if available.
I have 2 issues with this:
- It's only used in some parts (liblwgeom/ and libpgcommon/), while other folders know nothing about it.
- It's bad for precision (you voluntarily accept less precision) and, I guess, performance since you are not using the registers.
As of today, I get the same results for clang (without that option) and with GCC (which has that flag available), so I suggest dropping it altogether and in the case that we find some difference in an output, try to change it to allow both 80bit and 64bit precision in double operations.
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It became obsolete since we adopted C99 which implies -fexcess-precision=standard, which has the same executive effect as —ffloat-store but does not define how to do it ("by writing to registers"). I +1 to remove NUMERICFLAGS.
If you want to race for raw computation speed try making -ffast-math pass tests once again - it did for 2.5.