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authornaruse <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-03-07 03:35:47 +0000
committernaruse <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-03-07 03:35:47 +0000
commitac6f08df231d6f4972de75461a2a835c54fe1270 (patch)
tree0444aa77572bfb96a5b17e172486a8f8580eef0c
parentd4c598c441ef408fbab3db544d30525b5bc9c1e9 (diff)
Use ADD instead of MUL
* On recent CPUs, 2-operand MUL's latency is 3 cycle but ADD is 1 cycle. * clang Optimizes `MUL rax,2` into `ADD rax,rax` but gcc7 doesn't. * LONG2FIX is compiled into `lea r14,[r15+r15*1+0x1]`; this is 1cycle and run in parallel if the branch prediction is correct. * Note that old (RB_POSFIXABLE(f) && RB_NEGFIXABLE(f)) is usually uses following instructions. * movabs rax,0x4000000000000000 * add rax,rdi * js It needs large immediate and Macro-Fusion is not applied. ADD and JO is much smaller though it is also Macro-Fusion unfriendly. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57793 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--bignum.c10
-rw-r--r--include/ruby/ruby.h17
2 files changed, 5 insertions, 22 deletions
diff --git a/bignum.c b/bignum.c
index 50700b4..0e15e58 100644
--- a/bignum.c
+++ b/bignum.c
@@ -4436,18 +4436,8 @@ rb_ull2inum(unsigned LONG_LONG n)
VALUE
rb_ll2inum(LONG_LONG n)
{
-#ifdef HAVE_BUILTIN___BUILTIN_MUL_OVERFLOW
- SIGNED_VALUE v;
- if (__builtin_mul_overflow(n, 2, &v)) {
- return rb_ll2big(n);
- }
- else {
- return ((VALUE)v) | RUBY_FIXNUM_FLAG;
- }
-#else
if (FIXABLE(n)) return LONG2FIX(n);
return rb_ll2big(n);
-#endif
}
#endif /* HAVE_LONG_LONG */
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 0cd88fb..1cc9937 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -359,7 +359,11 @@ rb_fix2ulong(VALUE x)
#define RB_FIXNUM_P(f) (((int)(SIGNED_VALUE)(f))&RUBY_FIXNUM_FLAG)
#define RB_POSFIXABLE(f) ((f) < RUBY_FIXNUM_MAX+1)
#define RB_NEGFIXABLE(f) ((f) >= RUBY_FIXNUM_MIN)
-#define RB_FIXABLE(f) (RB_POSFIXABLE(f) && RB_NEGFIXABLE(f))
+#if defined HAVE_BUILTIN___BUILTIN_ADD_OVERFLOW
+# define RB_FIXABLE(f) ({SIGNED_VALUE a=(f),c; !__builtin_add_overflow(a, a, &c);})
+#else
+# define RB_FIXABLE(f) (RB_POSFIXABLE(f) && RB_NEGFIXABLE(f))
+#endif
#define FIX2LONG(x) RB_FIX2LONG(x)
#define FIX2ULONG(x) RB_FIX2ULONG(x)
#define FIXNUM_P(f) RB_FIXNUM_P(f)
@@ -1507,16 +1511,6 @@ rb_integer_type_p(VALUE obj)
static inline int
rb_long2fix_overflow(long l, VALUE *ptr)
{
-#ifdef HAVE_BUILTIN___BUILTIN_MUL_OVERFLOW
- SIGNED_VALUE v;
- if (__builtin_mul_overflow(l, 2, &v)) {
- return 1;
- }
- else {
- *ptr = ((VALUE)v) | RUBY_FIXNUM_FLAG;
- return 0;
- }
-#else
if (RB_FIXABLE(l)) {
*ptr = RB_LONG2FIX(l);
return 0;
@@ -1524,7 +1518,6 @@ rb_long2fix_overflow(long l, VALUE *ptr)
else {
return 1;
}
-#endif
}
#if SIZEOF_INT < SIZEOF_LONG