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| author | shyouhei <shyouhei@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2017-03-06 06:04:52 +0000 |
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| committer | shyouhei <shyouhei@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2017-03-06 06:04:52 +0000 |
| commit | 9d184819146bb7d24b30fc54ef206d9a592c9be4 (patch) | |
| tree | 508d56481df15bcd86ad634e7e25a19e6c55bc9a /configure.in | |
| parent | 60ac2d5cc84cf1aa0f4993211f73f22013349e1d (diff) | |
| download | ruby-9d184819146bb7d24b30fc54ef206d9a592c9be4.tar.gz | |
use HAVE_BUILTIN___BUILTIN_MUL_OVERFLOW
We already check for __builtin_mul_overflow in configure but never
actually referred it before. Why not call it if available, because
that should render supposedly-optimial assembly outputs.
Optionally if __builtin_mul_overflow_p is available, which is the case
for recent GCC, use that to detect fixnum overflow. This is much
faster than the previous. On my machine generated assembly of
numeric.c:int_pow reduces from 480 to 448 bytes, according to nm(1).
Also on my machine, following script boosts from 7.819 to 6.929 sec.
time ./miniruby -e 'i=0; while i < 30_000_000 do i += 1; 7 ** 23; end'
Signed-off-by: Urabe, Shyouhei <shyouhei@ruby-lang.org>
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57784 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'configure.in')
| -rw-r--r-- | configure.in | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/configure.in b/configure.in index 9eec2e9fa2..756f499387 100644 --- a/configure.in +++ b/configure.in @@ -2528,6 +2528,7 @@ RUBY_CHECK_BUILTIN_FUNC(__builtin_ctzll, [__builtin_ctzll(0)]) RUBY_CHECK_BUILTIN_FUNC(__builtin_add_overflow, [int x;__builtin_add_overflow(0,0,&x)]) RUBY_CHECK_BUILTIN_FUNC(__builtin_sub_overflow, [int x;__builtin_sub_overflow(0,0,&x)]) RUBY_CHECK_BUILTIN_FUNC(__builtin_mul_overflow, [int x;__builtin_mul_overflow(0,0,&x)]) +RUBY_CHECK_BUILTIN_FUNC(__builtin_mul_overflow_p, [__builtin_mul_overflow_p(0,0,(int)0)]) RUBY_CHECK_BUILTIN_FUNC(__builtin_constant_p, [__builtin_constant_p(0)]) RUBY_CHECK_BUILTIN_FUNC(__builtin_choose_expr, [ [int x[__extension__(__builtin_choose_expr(1, 1, -1))]]; |