Hi!
The following testcase fails with -fcompare-debug. The problem is that
bar is marked as address_taken only with -g and not without.
I've tracked it down to insert_init_stmt calling gimple_regimplify_operands
even on DEBUG_STMTs. That function will just insert normal stmts before
the DEBUG_STMT if the DEBUG_STMT operand isn't gimple val or invariant.
While DCE will turn those statements into debug temporaries, it can cause
differences in SSA_NAMEs and more importantly, the ipa references are
generated from those before the DCE happens.
On the testcase, the DEBUG_STMT value is (int)bar.
We could generate DEBUG_STMTs with debug temporaries instead, but I fail to
see the reason to do that, DEBUG_STMTs allow other expressions and all we
want to ensure is that the expressions aren't too large (arbitrarily
complex), but during inlining/function versioning I don't see why something
would queue a DEBUG_STMT with arbitrarily complex expressions in there.
So, this patch just doesn't regimplify DEBUG_STMTs. Bootstrapped/regtested
on x86_64-linux and i686-linux, ok for trunk?
2020-03-14 Jakub Jelinek <ja...@redhat.com>
PR debug/94167
* tree-inline.c (insert_init_stmt): Don't gimple_regimplify_operands
DEBUG_STMTs.
* gcc.dg/pr94167.c: New test.
--- gcc/tree-inline.c.jj 2020-03-04 12:58:35.033528551 +0100
+++ gcc/tree-inline.c 2020-03-13 16:19:04.129493354 +0100
@@ -3361,10 +3361,10 @@ insert_init_stmt (copy_body_data *id, ba
gimple_assign_set_rhs1 (init_stmt, rhs);
}
gsi_insert_after (&si, init_stmt, GSI_NEW_STMT);
- gimple_regimplify_operands (init_stmt, &si);
-
if (!is_gimple_debug (init_stmt))
{
+ gimple_regimplify_operands (init_stmt, &si);
+
tree def = gimple_assign_lhs (init_stmt);
insert_init_debug_bind (id, bb, def, def, init_stmt);
}
--- gcc/testsuite/gcc.dg/pr94167.c.jj 2020-03-13 16:33:34.046632902 +0100
+++ gcc/testsuite/gcc.dg/pr94167.c 2020-03-13 16:33:08.353012748 +0100
@@ -0,0 +1,33 @@
+/* PR debug/94167 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcompare-debug" } */
+
+struct S { int g, h; signed char i; int j; signed char k; int l[4]; } a, c;
+struct T { signed char g; } e;
+int *b, d;
+static void foo ();
+
+void
+bar (void)
+{
+ while (d)
+ {
+ int k;
+ struct T f[3];
+ foo (bar, a);
+ for (k = 0;; k++)
+ f[k] = e;
+ }
+}
+
+static inline void
+foo (int x, struct S y, struct T z)
+{
+ for (z.g = 2; z.g; z.g--)
+ {
+ c = a = y;
+ *b |= 6;
+ if (y.g)
+ break;
+ }
+}
Jakub
