Hi!
builtin_memref ctor for a SSA_NAME with non-NULL SSA_NAME_VAR returns
the underlying variable, rather than just the SSA_NAME.
Later on the code checks if the bases are equal and then compares
corresponding offsets.
The fact that two different SSA_NAMEs have the same underlying variable
says nothing at all whether they have the same value, as the testcase shows,
either the SSA_NAMEs can be completely unrelated, or related, but with
different offsets. The code already has code to handle POINTER_PLUS_EXPR
with a constant offset, to look through that. Perhaps in the future there
can be other cases we'd special case, but generally we should compare as
bases the SSA_NAMEs, if they have the same or different base says nothing
about them.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-01-25 Jakub Jelinek <ja...@redhat.com>
PR c/83989
* gimple-ssa-warn-restrict.c (builtin_memref::builtin_memref): Don't
use SSA_NAME_VAR as base for SSA_NAMEs with non-NULL SSA_NAME_VAR.
* c-c++-common/Wrestrict-3.c: New test.
--- gcc/gimple-ssa-warn-restrict.c.jj 2018-01-17 11:54:17.000000000 +0100
+++ gcc/gimple-ssa-warn-restrict.c 2018-01-25 14:10:26.182498552 +0100
@@ -373,9 +373,6 @@ builtin_memref::builtin_memref (tree exp
offrange[1] += off;
}
}
-
- if (TREE_CODE (base) == SSA_NAME && SSA_NAME_VAR (base))
- base = SSA_NAME_VAR (base);
}
if (size)
--- gcc/testsuite/c-c++-common/Wrestrict-3.c.jj 2018-01-25 14:16:01.574563425
+0100
+++ gcc/testsuite/c-c++-common/Wrestrict-3.c 2018-01-25 14:14:39.273547506
+0100
@@ -0,0 +1,48 @@
+/* PR c/83989 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wrestrict" } */
+
+__attribute__((__malloc__)) extern void *my_malloc (__SIZE_TYPE__);
+void baz (void *);
+
+#define SIZE 32
+
+void
+foo (void)
+{
+ void *recmem = __builtin_malloc (SIZE);
+ baz (recmem);
+ while (1)
+ {
+ void *oldrecmem = recmem;
+ recmem = __builtin_malloc (SIZE);
+ if (!recmem)
+ {
+ __builtin_free (oldrecmem);
+ return;
+ }
+ __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus
"accessing" } */
+ baz (recmem);
+ __builtin_free (oldrecmem);
+ }
+}
+
+void
+bar (void)
+{
+ void *recmem = my_malloc (SIZE);
+ baz (recmem);
+ while (1)
+ {
+ void *oldrecmem = recmem;
+ recmem = my_malloc (SIZE);
+ if (!recmem)
+ {
+ __builtin_free (oldrecmem);
+ return;
+ }
+ __builtin_memcpy (recmem, oldrecmem, SIZE); /* { dg-bogus
"accessing" } */
+ baz (recmem);
+ __builtin_free (oldrecmem);
+ }
+}
Jakub
