Without profiling information, GCC tends to assume "x == 1" and
"x + y == 2" are likely false, so this patch adds some __builtin_expects.
(system.h has a dummy definition for compilers that don't support
__builtin_expect.)
Tested on x86_64-linux-gnu. OK to install?
Thanks,
Richard
Index: gcc/wide-int.h
===================================================================
--- gcc/wide-int.h 2013-11-30 09:40:32.710196218 +0000
+++ gcc/wide-int.h 2013-11-30 10:07:06.567433289 +0000
@@ -1675,7 +1675,7 @@ wi::eq_p (const T1 &x, const T2 &y)
while (++i != xi.len);
return true;
}
- if (yi.len == 1)
+ if (__builtin_expect (yi.len == 1, true))
{
/* XI is only equal to YI if it too has a single HWI. */
if (xi.len != 1)
@@ -1751,7 +1751,7 @@ wi::ltu_p (const T1 &x, const T2 &y)
/* Optimize the case of two HWIs. The HWIs are implicitly sign-extended
for precisions greater than HOST_BITS_WIDE_INT, but sign-extending both
values does not change the result. */
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
unsigned HOST_WIDE_INT xl = xi.to_uhwi ();
unsigned HOST_WIDE_INT yl = yi.to_uhwi ();
@@ -1922,7 +1922,7 @@ wi::cmpu (const T1 &x, const T2 &y)
/* Optimize the case of two HWIs. The HWIs are implicitly sign-extended
for precisions greater than HOST_BITS_WIDE_INT, but sign-extending both
values does not change the result. */
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
unsigned HOST_WIDE_INT xl = xi.to_uhwi ();
unsigned HOST_WIDE_INT yl = yi.to_uhwi ();
@@ -2128,7 +2128,7 @@ wi::bit_and (const T1 &x, const T2 &y)
WIDE_INT_REF_FOR (T1) xi (x, precision);
WIDE_INT_REF_FOR (T2) yi (y, precision);
bool is_sign_extended = xi.is_sign_extended && yi.is_sign_extended;
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
val[0] = xi.ulow () & yi.ulow ();
result.set_len (1, is_sign_extended);
@@ -2149,7 +2149,7 @@ wi::bit_and_not (const T1 &x, const T2 &
WIDE_INT_REF_FOR (T1) xi (x, precision);
WIDE_INT_REF_FOR (T2) yi (y, precision);
bool is_sign_extended = xi.is_sign_extended && yi.is_sign_extended;
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
val[0] = xi.ulow () & ~yi.ulow ();
result.set_len (1, is_sign_extended);
@@ -2170,7 +2170,7 @@ wi::bit_or (const T1 &x, const T2 &y)
WIDE_INT_REF_FOR (T1) xi (x, precision);
WIDE_INT_REF_FOR (T2) yi (y, precision);
bool is_sign_extended = xi.is_sign_extended && yi.is_sign_extended;
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
val[0] = xi.ulow () | yi.ulow ();
result.set_len (1, is_sign_extended);
@@ -2191,7 +2191,7 @@ wi::bit_or_not (const T1 &x, const T2 &y
WIDE_INT_REF_FOR (T1) xi (x, precision);
WIDE_INT_REF_FOR (T2) yi (y, precision);
bool is_sign_extended = xi.is_sign_extended && yi.is_sign_extended;
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
val[0] = xi.ulow () | ~yi.ulow ();
result.set_len (1, is_sign_extended);
@@ -2212,7 +2212,7 @@ wi::bit_xor (const T1 &x, const T2 &y)
WIDE_INT_REF_FOR (T1) xi (x, precision);
WIDE_INT_REF_FOR (T2) yi (y, precision);
bool is_sign_extended = xi.is_sign_extended && yi.is_sign_extended;
- if (xi.len + yi.len == 2)
+ if (__builtin_expect (xi.len + yi.len == 2, true))
{
val[0] = xi.ulow () ^ yi.ulow ();
result.set_len (1, is_sign_extended);
@@ -2248,7 +2248,7 @@ wi::add (const T1 &x, const T2 &y)
HOST_BITS_PER_WIDE_INT are relatively rare and there's not much
point handling them inline. */
else if (STATIC_CONSTANT_P (precision > HOST_BITS_PER_WIDE_INT)
- && xi.len + yi.len == 2)
+ && __builtin_expect (xi.len + yi.len == 2, true))
{
unsigned HOST_WIDE_INT xl = xi.ulow ();
unsigned HOST_WIDE_INT yl = yi.ulow ();
@@ -2323,7 +2323,7 @@ wi::sub (const T1 &x, const T2 &y)
HOST_BITS_PER_WIDE_INT are relatively rare and there's not much
point handling them inline. */
else if (STATIC_CONSTANT_P (precision > HOST_BITS_PER_WIDE_INT)
- && xi.len + yi.len == 2)
+ && __builtin_expect (xi.len + yi.len == 2, true))
{
unsigned HOST_WIDE_INT xl = xi.ulow ();
unsigned HOST_WIDE_INT yl = yi.ulow ();
