Commit Graph

7 Commits

Author SHA1 Message Date
Rémi Verschelde
c2a669a9f0 SCons: Review uses of CCFLAGS, CXXFLAGS and CPPFLAGS
Many contributors (me included) did not fully understand what CCFLAGS,
CXXFLAGS and CPPFLAGS refer to exactly, and were thus not using them
in the way they are intended to be.

As per the SCons manual: https://www.scons.org/doc/HTML/scons-user/apa.html

- CCFLAGS: General options that are passed to the C and C++ compilers.
- CFLAGS: General options that are passed to the C compiler (C only;
  not C++).
- CXXFLAGS: General options that are passed to the C++ compiler. By
  default, this includes the value of $CCFLAGS, so that setting
  $CCFLAGS affects both C and C++ compilation.
- CPPFLAGS: User-specified C preprocessor options. These will be
  included in any command that uses the C preprocessor, including not
  just compilation of C and C++ source files [...], but also [...]
  Fortran [...] and [...] assembly language source file[s].

TL;DR: Compiler options go to CCFLAGS, unless they must be restricted
to either C (CFLAGS) or C++ (CXXFLAGS). Preprocessor defines go to
CPPFLAGS.
2019-04-24 16:57:58 +02:00
Hein-Pieter van Braam
e5b335d367 Don't use -ffast-math or other unsafe math optimizations
Godot supports many different compilers and for production releases we
have to support 3 currently: GCC8, Clang6, and MSVC2017. These compilers
all do slightly different things with -ffast-math and it is causing
issues now. See #24841, #24540, #10758, #10070. And probably other
complaints about physics differences between release and release_debug
builds.

I've done some performance comparisons on Linux x86_64. All tests are
ran 20 times.

Bunnymark: (higher is better)
(bunnies)    min    max  stdev average
fast-math   7332   7597    71     7432
this pr     7379   7779   108     7621 (102%)

FPBench (gdscript port http://fpbench.org/) (lower is better)
(ms)
fast-math  15441  16127   192    15764
this pr    15671  16855   326    16001  (99%)

Float_add (adding floats in a tight loop) (lower is better)
(sec)
fast-math   5.49   5.78  0.07     5.65
this pr     5.65   5.90  0.06     5.76  (98%)

Float_div (dividing floats in a tight loop) (lower is better)
(sec)
fast-math  11.70  12.36  0.18    11.99
this pr    11.92  12.32  0.12    12.12  (99%)

Float_mul (multiplying floats in a tight loop) (lower is better)
(sec)
fast-math  11.72  12.17  0.12    11.93
this pr    12.01  12.62  0.17    12.26  (97%)

I have also looked at FPS numbers for tps-demo, 3d platformer, 2d
platformer, and sponza and could not find any measurable difference.

I believe that given the issues and oft-reported (physics) glitches on
release builds I believe that the couple of percent of tight-loop
floating point performance regression is well worth it.

This fixes #24540 and fixes #24841
2019-01-09 02:06:13 +01:00
Rémi Verschelde
3a2ca68af3 SCons: Build thirdparty code in own env, disable warnings
Also remove unnecessary `Export('env')` in other SCsubs,
Export should only be used when exporting *new* objects.
2018-09-28 14:07:39 +02:00
Matthias Hoelzl
26a1621678 Change -std=gnu++11 to -stc=c++11 and don't pass flag to MSVC 2017-12-12 18:58:51 +01:00
Ignacio Etcheverry
2f79c84ff5 etc: Append -std=gnu++11 to CCFLAGS instead of CXXFLAGS
This way it can override the -std flags passed to scons.
2017-09-01 18:51:50 +02:00
Hein-Pieter van Braam
d44414c711 Disable -ffast-math for etc2comp
Apparently -ffast-math generates incorrect code with recent versions of
GCC and Clang. The manual page for GCC warns about this possibility.

In my tests it doesn't actually appear to be measurably slower in this
case, and this is used in a batch process so it seems safe to disable
this.

This fixes #10758 and fixes #10070
2017-08-30 11:51:24 +02:00
Ferenc Arn
6a9c990da7 Add ETC1/ETC2 compression support though etc2comp.
Remove rg-etc1 code. Also updated travis to use ubuntu 14.04.

Fixes #8457.
2017-05-31 18:59:00 -05:00