TeamHeptaMirrors/gcc
1
0
Fork 1
mirror of https://github.com/gcc-mirror/gcc.git synced 2026-05-06 14:59:39 +02:00
Code Issues Packages Projects Releases Wiki Activity

gimplify: Fix ICE in collect_fallthrough_labels [PR122773]

Browse Source 
In r16-4212 I had to tweak two spots in the gimplifier to ignore
gotos jumping to labels with the new VACUOUS_INIT_LABEL_P flag
(set by C++ FE when implementing goto/case interceptors with
extra .DEFERRED_INIT calls, so that jumps over vacuous initialization
are handled properly with the C++26 erroneous behavior requirements).
Except as the following testcase shows, the checks blindly assumed
that gimple_goto_dest operand is a LABEL_DECL, which is not the case
for computed jumps.

The following patch checks that gimple_goto_dest argument is a LABEL_DECL
before testing VACUOUS_INIT_LABEL_P flag on it.

2025-11-21  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/122773
	* gimplify.cc (collect_fallthrough_labels): Check whether
	gimple_goto_dest is a LABEL_DECL before testing VACUOUS_INIT_LABEL_P.
	(expand_FALLTHROUGH_r): Likewise.

	* gcc.dg/pr122773.c: New test.
This commit is contained in:
Jakub Jelinek
2025-11-21 11:25:27 +01:00
committed by Jakub Jelinek
parent c435bbdd22
commit 3012aad2dc
2 changed files with 33 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
gcc/gimplify.cc
View File

@@ -2673,6 +2673,7 @@ collect_fallthrough_labels (gimple_stmt_iterator *gsi_p,
gsi_next (gsi_p);
}
tree lab;
/* Remember the last statement. Skip labels that are of no interest
to us. */
if (gimple_code (gsi_stmt (*gsi_p)) == GIMPLE_LABEL)
@@ -2691,7 +2692,9 @@ collect_fallthrough_labels (gimple_stmt_iterator *gsi_p,
;
else if (flag_auto_var_init > AUTO_INIT_UNINITIALIZED
&& gimple_code (gsi_stmt (*gsi_p)) == GIMPLE_GOTO
&& VACUOUS_INIT_LABEL_P (gimple_goto_dest (gsi_stmt (*gsi_p))))
&& (lab = gimple_goto_dest (gsi_stmt (*gsi_p)))
&& TREE_CODE (lab) == LABEL_DECL
&& VACUOUS_INIT_LABEL_P (lab))
;
else if (!is_gimple_debug (gsi_stmt (*gsi_p)))
prev = gsi_stmt (*gsi_p);
@@ -2928,9 +2931,12 @@ expand_FALLTHROUGH_r (gimple_stmt_iterator *gsi_p, bool *handled_ops_p,
gimple_stmt_iterator gsi2 = *gsi_p;
stmt = gsi_stmt (gsi2);
tree lab;
if (flag_auto_var_init > AUTO_INIT_UNINITIALIZED
&& gimple_code (stmt) == GIMPLE_GOTO
&& VACUOUS_INIT_LABEL_P (gimple_goto_dest (stmt)))
&& (lab = gimple_goto_dest (stmt))
&& TREE_CODE (lab) == LABEL_DECL
&& VACUOUS_INIT_LABEL_P (lab))
{
/* Handle for C++ artificial -ftrivial-auto-var-init=
sequences. Those look like:

25
gcc/testsuite/gcc.dg/pr122773.c Normal file
View File

@@ -0,0 +1,25 @@
/* PR middle-end/122773 */
/* { dg-do compile } */
/* { dg-options "-Wimplicit-fallthrough -O2 -ftrivial-auto-var-init=zero" } */
void *l;
int
foo (int x)
{
__label__ l1, l2, l3;
static void *l[] = { &&l1, &&l2, &&l3 };
switch (0)
{
case 0:
while (0)
;
goto *l[x];
}
l1:
++x;
l2:
++x;
l3:
++x;
return x;
}