gcc/testsuite/gcc.dg/tree-ssa/pr96789.c

   1 /* { dg-do compile } */
   2 /* Disable loop vectorization to avoid that loop vectorizer
   3    optimizes those two loops that operate tmp array so that
   4    subsequent dse3 won't eliminate expected tmp stores.  */
   5 /* { dg-options "-O2 -funroll-loops -ftree-slp-vectorize -fno-tree-loop-vectorize -fdump-tree-dse-details" } */
   6
   7 /* Test if scalar cleanup pass takes effects, mainly check
   8    its secondary pass DSE can remove dead stores on array
   9    tmp.  */
  10
  11 #include "stdint.h"
  12
  13 static inline void
  14 foo (int16_t *diff, int i_size, uint8_t *val1, int i_val1, uint8_t *val2,
  15      int i_val2)
  16 {
  17   for (int y = 0; y < i_size; y++)
  18     {
  19       for (int x = 0; x < i_size; x++)
  20         diff[x + y * i_size] = val1[x] - val2[x];
  21       val1 += i_val1;
  22       val2 += i_val2;
  23     }
  24 }
  25
  26 void
  27 bar (int16_t res[16], uint8_t *val1, uint8_t *val2)
  28 {
  29   int16_t d[16];
  30   int16_t tmp[16];
  31
  32   foo (d, 4, val1, 16, val2, 32);
  33
  34   for (int i = 0; i < 4; i++)
  35     {
  36       int s03 = d[i * 4 + 0] + d[i * 4 + 3];
  37       int s12 = d[i * 4 + 1] + d[i * 4 + 2];
  38       int d03 = d[i * 4 + 0] - d[i * 4 + 3];
  39       int d12 = d[i * 4 + 1] - d[i * 4 + 2];
  40
  41       tmp[0 * 4 + i] = s03 + s12;
  42       tmp[1 * 4 + i] = 2 * d03 + d12;
  43       tmp[2 * 4 + i] = s03 - s12;
  44       tmp[3 * 4 + i] = d03 - 2 * d12;
  45     }
  46
  47   for (int i = 0; i < 4; i++)
  48     {
  49       int s03 = tmp[i * 4 + 0] + tmp[i * 4 + 3];
  50       int s12 = tmp[i * 4 + 1] + tmp[i * 4 + 2];
  51       int d03 = tmp[i * 4 + 0] - tmp[i * 4 + 3];
  52       int d12 = tmp[i * 4 + 1] - tmp[i * 4 + 2];
  53
  54       res[i * 4 + 0] = s03 + s12;
  55       res[i * 4 + 1] = 2 * d03 + d12;
  56       res[i * 4 + 2] = s03 - s12;
  57       res[i * 4 + 3] = d03 - 2 * d12;
  58     }
  59 }
  60
  61 /* { dg-final { scan-tree-dump {Deleted dead store:.*tmp} "dse4" } } */