------- Comment #1 from rguenth at gcc dot gnu dot org 2009-08-01 14:58 -------
This is because of the differences in the IL C vs. C++.
C has
r0 = (short unsigned int) *pcr - (short unsigned int) *ppr;
r1 = (short unsigned int) *pcg - (short unsigned int) *ppg;
r2 = (short unsigned int) *pcb - (short unsigned int) *ppb;
r0 = (r0 >> 8 | 65280) & r0;
r1 = (r1 >> 8 | 65280) & r1;
r2 = (r2 >> 8 | 65280) & r2;
short unsigned int r = (r0 + r1) + r2;
*n = (*n + r) - (*n >> 5);
*o = (unsigned char) r;
while C++ does (EH stuff stripped):
r0 = (short unsigned int) *(unsigned char *) pcr - (short unsigned int)
*(unsigned char *) ppr;
r1 = (short unsigned int) *(unsigned char *) pcg - (short unsigned int)
*(unsigned char *) ppg;
r2 = (short unsigned int) *(unsigned char *) pcb - (short unsigned int)
*(unsigned char *) ppb;
r0 = (short unsigned int) (((short int) ((int) r0 >> 8) | -256) & (short int)
r0);
r1 = (short unsigned int) (((short int) ((int) r1 >> 8) | -256) & (short int)
r1);
r2 = (short unsigned int) (((short int) ((int) r2 >> 8) | -256) & (short int)
r2);
r = (r0 + r1) + r2;
*(short unsigned int *) n = (*(short unsigned int *) n + r) - (short unsigned
int) ((int) *(short unsigned int *) n >> 5);
*(unsigned char *) o = (unsigned char) r;
which looks unfolded compared to what C ends up with (the C FE shortens
the BIT_IOR_EXPR to unsigned short, something fold should do instead).
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2009-08-01 14:58:34
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40927
