[Bug tree-optimization/43224] Constant load not raised out of loop

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2010-03-02 03:53 -------
I think what GCC is doing is correct as lsps could conflict with mul_q and
base_q as lsps is not marked as restrict.
Doing this:
#include <string.h>

void dequant_lsps(double *__restrict lsps, int num,
                 const unsigned short *values,
                 int n_stages, const unsigned char * __restrict table,
                 const double * __restrict mul_q, const double * __restrict
base_q)
{
   const unsigned char * __restrict t_off = &table[values[0] * num];
   int m;

   memset(lsps, 0, num * sizeof(*lsps));

       for (m = 0; m < num; m++)
       lsps[m] += base_q[0] + mul_q[0] * t_off[m];
}

Allows GCC to optimize those loads away.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43224