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re PR middle-end/36041 (Speed up builtin_popcountll)

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PR middle-end/36041
	* libgcc2.c (POPCOUNTCST2, POPCOUNTCST4, POPCOUNTCST8, POPCOUNTCST):
	Define.
	(__popcountSI2): For __SIZEOF_INT__ > 2 targets use arithmetics
	instead of table lookups.
	(__popcountDI2): Likewise.

From-SVN: r200506
This commit is contained in:
Jakub Jelinek 2013-06-28 11:28:40 +02:00 committed by Jakub Jelinek
parent ebf8f0eaeb
commit 4ea3d77451
2 changed files with 50 additions and 0 deletions
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9
libgcc/ChangeLog
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@ -1,3 +1,12 @@
2013-06-28 Jakub Jelinek <jakub@redhat.com>
PR middle-end/36041
* libgcc2.c (POPCOUNTCST2, POPCOUNTCST4, POPCOUNTCST8, POPCOUNTCST):
Define.
(__popcountSI2): For __SIZEOF_INT__ > 2 targets use arithmetics
instead of table lookups.
(__popcountDI2): Likewise.
2013-06-25 Chung-Ju Wu <jasonwucj@gmail.com>
* Makefile.in (clean, distclean): Remove auto-target.h and stamp-h

41
libgcc/libgcc2.c
View File

@ -819,17 +819,42 @@ const UQItype __popcount_tab[256] =
};
#endif
#if defined(L_popcountsi2) || defined(L_popcountdi2)
#define POPCOUNTCST2(x) (((UWtype) x << BITS_PER_UNIT) | x)
#define POPCOUNTCST4(x) (((UWtype) x << (2 * BITS_PER_UNIT)) | x)
#define POPCOUNTCST8(x) (((UWtype) x << (4 * BITS_PER_UNIT)) | x)
#if W_TYPE_SIZE == BITS_PER_UNIT
#define POPCOUNTCST(x) x
#elif W_TYPE_SIZE == 2 * BITS_PER_UNIT
#define POPCOUNTCST(x) POPCOUNTCST2 (x)
#elif W_TYPE_SIZE == 4 * BITS_PER_UNIT
#define POPCOUNTCST(x) POPCOUNTCST4 (POPCOUNTCST2 (x))
#elif W_TYPE_SIZE == 8 * BITS_PER_UNIT
#define POPCOUNTCST(x) POPCOUNTCST8 (POPCOUNTCST4 (POPCOUNTCST2 (x)))
#endif
#endif
#ifdef L_popcountsi2
#undef int
int
__popcountSI2 (UWtype x)
{
/* Force table lookup on targets like AVR and RL78 which only
pretend they have LIBGCC2_UNITS_PER_WORD 4, but actually
have 1, and other small word targets. */
#if __SIZEOF_INT__ > 2 && defined (POPCOUNTCST) && BITS_PER_UNIT == 8
x = x - ((x >> 1) & POPCOUNTCST (0x55));
x = (x & POPCOUNTCST (0x33)) + ((x >> 2) & POPCOUNTCST (0x33));
x = (x + (x >> 4)) & POPCOUNTCST (0x0F);
return (x * POPCOUNTCST (0x01)) >> (W_TYPE_SIZE - BITS_PER_UNIT);
#else
int i, ret = 0;
for (i = 0; i < W_TYPE_SIZE; i += 8)
ret += __popcount_tab[(x >> i) & 0xff];
return ret;
#endif
}
#endif
@ -838,12 +863,28 @@ __popcountSI2 (UWtype x)
int
__popcountDI2 (UDWtype x)
{
/* Force table lookup on targets like AVR and RL78 which only
pretend they have LIBGCC2_UNITS_PER_WORD 4, but actually
have 1, and other small word targets. */
#if __SIZEOF_INT__ > 2 && defined (POPCOUNTCST) && BITS_PER_UNIT == 8
const DWunion uu = {.ll = x};
UWtype x1 = uu.s.low, x2 = uu.s.high;
x1 = x1 - ((x1 >> 1) & POPCOUNTCST (0x55));
x2 = x2 - ((x2 >> 1) & POPCOUNTCST (0x55));
x1 = (x1 & POPCOUNTCST (0x33)) + ((x1 >> 2) & POPCOUNTCST (0x33));
x2 = (x2 & POPCOUNTCST (0x33)) + ((x2 >> 2) & POPCOUNTCST (0x33));
x1 = (x1 + (x1 >> 4)) & POPCOUNTCST (0x0F);
x2 = (x2 + (x2 >> 4)) & POPCOUNTCST (0x0F);
x1 += x2;
return (x1 * POPCOUNTCST (0x01)) >> (W_TYPE_SIZE - BITS_PER_UNIT);
#else
int i, ret = 0;
for (i = 0; i < 2*W_TYPE_SIZE; i += 8)
ret += __popcount_tab[(x >> i) & 0xff];
return ret;
#endif
}
#endif