[gcc r15-791] tree-optimization/115138 - ptr-vs-ptr and FUNCTION_DECLs

[Richard Biener via Gcc-cvs]

https://gcc.gnu.org/g:61f5b3c59ed20438d7d9918d7a83d29a21097d4e

commit r15-791-g61f5b3c59ed20438d7d9918d7a83d29a21097d4e
Author: Richard Biener <rguent...@suse.de>
Date:   Thu May 23 11:26:14 2024 +0200

    tree-optimization/115138 - ptr-vs-ptr and FUNCTION_DECLs
    
    I failed to realize we do not represent FUNCTION_DECLs or LABEL_DECLs
    in vars explicitly and thus have to compare pt.vars_contains_nonlocal.
    
            PR tree-optimization/115138
            * tree-ssa-alias.cc (ptrs_compare_unequal): Make sure
            pt.vars_contains_nonlocal differs since we do not represent
            FUNCTION_DECLs or LABEL_DECLs in vars explicitly.
    
            * gcc.dg/torture/pr115138.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr115138.c | 28 ++++++++++++++++++++++++++++
 gcc/tree-ssa-alias.cc                   |  6 ++++++
 2 files changed, 34 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/torture/pr115138.c 
b/gcc/testsuite/gcc.dg/torture/pr115138.c
new file mode 100644
index 00000000000..6becaecbaff
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr115138.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+
+int foo (int) {}
+int bar (int) {}
+
+typedef int (*pred)(int);
+
+int x, y;
+pred A () { if (x) return foo; else return bar; }
+pred B () { if (y) return foo; else return bar; }
+int __attribute__((noipa)) baz()
+{
+  pred a = A();
+  pred b = B();
+  if (a != b)
+    return 42;
+  return 0;
+}
+
+int main()
+{
+  if (baz () != 0)
+    __builtin_abort ();
+  y = 1;
+  if (baz () != 42)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index d64d6d02f4a..1a91d63a31e 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -501,6 +501,12 @@ ptrs_compare_unequal (tree ptr1, tree ptr2)
              || pi2->pt.vars_contains_interposable)
            return false;
          if ((!pi1->pt.null || !pi2->pt.null)
+             /* ???  We do not represent FUNCTION_DECL and LABEL_DECL
+                in pt.vars but only set pt.vars_contains_nonlocal.  This
+                makes compares involving those and other nonlocals
+                imprecise.  */
+             && (!pi1->pt.vars_contains_nonlocal
+                 || !pi2->pt.vars_contains_nonlocal)
              && (!pt_solution_includes_const_pool (&pi1->pt)
                  || !pt_solution_includes_const_pool (&pi2->pt)))
            return !pt_solutions_intersect (&pi1->pt, &pi2->pt);