[gcc r15-792] tree-optimization/115199 - fix PTA constraint processing for &ANYTHING LHS

[Richard Biener via Gcc-cvs]

https://gcc.gnu.org/g:f0a02467bbc35a478eb82f5a8a7e8870827b51fc

commit r15-792-gf0a02467bbc35a478eb82f5a8a7e8870827b51fc
Author: Richard Biener <rguent...@suse.de>
Date:   Thu May 23 13:33:15 2024 +0200

    tree-optimization/115199 - fix PTA constraint processing for &ANYTHING LHS
    
    When processing a &ANYTHING = X constraint we treat it as *ANYTHING = X
    during constraint processing but then end up recording it as
    &ANYTHING = X anyway, breaking constraint graph building.  This is
    because we only update the local copy of the LHS and not the constraint
    itself.
    
            PR tree-optimization/115199
            * tree-ssa-structalias.cc (process_constraint): Also
            record &ANYTHING = X as *ANYTING = X in the end.
    
            * gcc.dg/torture/pr115199.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr115199.c | 24 ++++++++++++++++++++++++
 gcc/tree-ssa-structalias.cc             |  2 +-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr115199.c 
b/gcc/testsuite/gcc.dg/torture/pr115199.c
new file mode 100644
index 00000000000..981a7330b32
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr115199.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+
+struct b {
+  char *volatile c;
+};
+struct b * __attribute__((noipa))
+d()
+{
+  char *e;
+  struct b *b = __builtin_malloc(sizeof(b));
+  void *f = __builtin_malloc(1);
+
+  e = __builtin_memcpy(f, "z", 1);
+  b->c = e;
+  return b;
+}
+
+int main()
+{
+  struct b b = *d();
+  if (b.c[0] != 'z')
+    __builtin_abort();
+  return 0;
+}
diff --git a/gcc/tree-ssa-structalias.cc b/gcc/tree-ssa-structalias.cc
index 0e9423a78ec..a39b36c146e 100644
--- a/gcc/tree-ssa-structalias.cc
+++ b/gcc/tree-ssa-structalias.cc
@@ -3104,7 +3104,7 @@ process_constraint (constraint_t t)
      it here by turning it into *ANYTHING.  */
   if (lhs.type == ADDRESSOF
       && lhs.var == anything_id)
-    lhs.type = DEREF;
+    t->lhs.type = lhs.type = DEREF;
 
   /* ADDRESSOF on the lhs is invalid.  */
   gcc_assert (lhs.type != ADDRESSOF);