toolchain/gcc/patches-13.x/001-rtl-optimization-109585-alias-analysis-typo.patch

   1 From bb406a6aea336966681927a27f54ee89c4fd4ea1 Mon Sep 17 00:00:00 2001
   2 From: Richard Biener <rguenther@suse.de>
   3 Date: Mon, 24 Apr 2023 13:31:07 +0200
   4 Subject: [PATCH] rtl-optimization/109585 - alias analysis typo
   5
   6 When r10-514-gc6b84edb6110dd2b4fb improved access path analysis
   7 it introduced a typo that triggers when there's an access to a
   8 trailing array in the first access path leading to false
   9 disambiguation.
  10
  11         PR rtl-optimization/109585
  12         * tree-ssa-alias.cc (aliasing_component_refs_p): Fix typo.
  13
  14         * gcc.dg/torture/pr109585.c: New testcase.
  15
  16 (cherry picked from commit 6d4bd27a60447c7505cb4783e675e98a191a8904)
  17 ---
  18  gcc/testsuite/gcc.dg/torture/pr109585.c | 33 +++++++++++++++++++++++++
  19  gcc/tree-ssa-alias.cc                   |  2 +-
  20  2 files changed, 34 insertions(+), 1 deletion(-)
  21  create mode 100644 gcc/testsuite/gcc.dg/torture/pr109585.c
  22
  23 --- /dev/null
  24 +++ b/gcc/testsuite/gcc.dg/torture/pr109585.c
  25 @@ -0,0 +1,33 @@
  26 +/* { dg-do run } */
  27 +
  28 +#include <stdlib.h>
  29 +
  30 +struct P {
  31 +    long v;
  32 +    struct P *n;
  33 +};
  34 +
  35 +struct F {
  36 +    long x;
  37 +    struct P fam[];
  38 +};
  39 +
  40 +int __attribute__((noipa))
  41 +f(struct F *f, int i)
  42 +{
  43 +  struct P *p = f->fam;
  44 +  asm("" : "+r"(f): "r"(p));
  45 +  p->v = 0;
  46 +  p->n = 0;
  47 +  return f->fam->n != 0;
  48 +}
  49 +
  50 +int
  51 +main()
  52 +{
  53 +  struct F *m = malloc (sizeof (long) + 2 * sizeof (struct P));
  54 +  m->fam[0].n = &m->fam[1];
  55 +  if (f (m, 0))
  56 +    abort ();
  57 +  return 0;
  58 +}
  59 --- a/gcc/tree-ssa-alias.cc
  60 +++ b/gcc/tree-ssa-alias.cc
  61 @@ -1330,7 +1330,7 @@ aliasing_component_refs_p (tree ref1,
  62    /* If we didn't find a common base, try the other way around.  */
  63    if (cmp_outer <= 0
  64        || (end_struct_ref1
  65 -         && compare_type_sizes (TREE_TYPE (end_struct_ref1), type1) <= 0))
  66 +         && compare_type_sizes (TREE_TYPE (end_struct_ref1), type2) <= 0))
  67      {
  68        int res = aliasing_component_refs_walk (ref2, type2, base2,
  69                                               offset2, max_size2,