On Sat, 14 Mar 2020, Jakub Jelinek wrote:
> 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?
OK.
Thanks,
Richard.
> 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
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
