From: Nick Hainke <vincent@systemli.org>
Date: Wed, 3 May 2023 14:46:52 +0000 (+0200)
Subject: toolchain: gcc: backport patch for gcc 13 fixing access path analysis
X-Git-Tag: v23.05.0-rc1~333
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=a6d689632c5326e4869937c0ff5f9c72f6190729;p=openwrt%2Fstaging%2Fpepe2k.git

toolchain: gcc: backport patch for gcc 13 fixing access path analysis

While improving access path analysis a typo happened. Now it can happen
that gcc misscompiles. The patch is fixing the issue. However, also
other gcc versions 10.2+ are affected. They also should be bumped or the
fix should be backported.

For more bug information have a look at:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109585

Signed-off-by: Nick Hainke <vincent@systemli.org>
---

diff --git a/toolchain/gcc/patches-13.x/001-rtl-optimization-109585-alias-analysis-typo.patch b/toolchain/gcc/patches-13.x/001-rtl-optimization-109585-alias-analysis-typo.patch
new file mode 100644
index 0000000000..7f73be4325
--- /dev/null
+++ b/toolchain/gcc/patches-13.x/001-rtl-optimization-109585-alias-analysis-typo.patch
@@ -0,0 +1,69 @@
+From bb406a6aea336966681927a27f54ee89c4fd4ea1 Mon Sep 17 00:00:00 2001
+From: Richard Biener <rguenther@suse.de>
+Date: Mon, 24 Apr 2023 13:31:07 +0200
+Subject: [PATCH] rtl-optimization/109585 - alias analysis typo
+
+When r10-514-gc6b84edb6110dd2b4fb improved access path analysis
+it introduced a typo that triggers when there's an access to a
+trailing array in the first access path leading to false
+disambiguation.
+
+	PR rtl-optimization/109585
+	* tree-ssa-alias.cc (aliasing_component_refs_p): Fix typo.
+
+	* gcc.dg/torture/pr109585.c: New testcase.
+
+(cherry picked from commit 6d4bd27a60447c7505cb4783e675e98a191a8904)
+---
+ gcc/testsuite/gcc.dg/torture/pr109585.c | 33 +++++++++++++++++++++++++
+ gcc/tree-ssa-alias.cc                   |  2 +-
+ 2 files changed, 34 insertions(+), 1 deletion(-)
+ create mode 100644 gcc/testsuite/gcc.dg/torture/pr109585.c
+
+--- /dev/null
++++ b/gcc/testsuite/gcc.dg/torture/pr109585.c
+@@ -0,0 +1,33 @@
++/* { dg-do run } */
++
++#include <stdlib.h>
++
++struct P {
++    long v;
++    struct P *n;
++};
++
++struct F {
++    long x;
++    struct P fam[];
++};
++
++int __attribute__((noipa))
++f(struct F *f, int i)
++{
++  struct P *p = f->fam;
++  asm("" : "+r"(f): "r"(p));
++  p->v = 0;
++  p->n = 0;
++  return f->fam->n != 0;
++}
++
++int
++main()
++{
++  struct F *m = malloc (sizeof (long) + 2 * sizeof (struct P));
++  m->fam[0].n = &m->fam[1];
++  if (f (m, 0))
++    abort ();
++  return 0;
++}
+--- a/gcc/tree-ssa-alias.cc
++++ b/gcc/tree-ssa-alias.cc
+@@ -1330,7 +1330,7 @@ aliasing_component_refs_p (tree ref1,
+   /* If we didn't find a common base, try the other way around.  */
+   if (cmp_outer <= 0 
+       || (end_struct_ref1
+-	  && compare_type_sizes (TREE_TYPE (end_struct_ref1), type1) <= 0))
++	  && compare_type_sizes (TREE_TYPE (end_struct_ref1), type2) <= 0))
+     {
+       int res = aliasing_component_refs_walk (ref2, type2, base2,
+ 					      offset2, max_size2,