mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-04 12:01:06 +08:00
Code Issues Packages Projects Releases Wiki Activity

c-family: Fix PR94272 -fcompare-debug issue even for C [PR99230]

Browse Source 
The following testcase results in -fcompare-debug failure.
The problem is the similar like in PR94272
https://gcc.gnu.org/pipermail/gcc-patches/2020-March/542562.html
When genericizing, with -g0 we have just a TREE_SIDE_EFFECTS DO_STMT
in a branch of if, while with -g we have that wrapped into
TREE_SIDE_EFFECTS STATEMENT_LIST containing DEBUG_BEGIN_STMT and that
DO_STMT.
The do loop is empty with 0 condition, so c_genericize_control_stmt
turns it into an empty statement (without TREE_SIDE_EFFECTS).
For -g0 that means that suddenly the if branch doesn't have side effects
and is expanded differently.  But with -g we still have TREE_SIDE_EFFECTS
STATEMENT_LIST containing DEBUG_BEGIN_STMT and non-TREE_SIDE_EFFECTS stmt.
The following patch fixes that by detecting this case and removing
TREE_SIDE_EFFECTS.

And, so that we don't duplicate the same code, changes the C++ FE to
just call the c_genericize_control_stmt function that can now handle it.

2021-03-20  Jakub Jelinek  <jakub@redhat.com>

	PR debug/99230
	* c-gimplify.c (c_genericize_control_stmt): Handle STATEMENT_LIST.

	* cp-gimplify.c (cp_genericize_r) <case STATEMENT_LIST>: Remove
	special code, instead call c_genericize_control_stmt.

	* gcc.dg/pr99230.c: New test.
This commit is contained in:
Jakub Jelinek 2021-03-20 17:02:06 +01:00
parent 9c2f08475a
commit 9f59cb7cac
3 changed files with 70 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
gcc/c-family/c-gimplify.c
View File

@ -497,6 +497,35 @@ c_genericize_control_stmt (tree *stmt_p, int *walk_subtrees, void *data,
genericize_omp_for_stmt (stmt_p, walk_subtrees, data, func, lh);
break;
case STATEMENT_LIST:
if (TREE_SIDE_EFFECTS (stmt))
{
tree_stmt_iterator i;
int nondebug_stmts = 0;
bool clear_side_effects = true;
/* Genericization can clear TREE_SIDE_EFFECTS, e.g. when
transforming an IF_STMT into COND_EXPR. If such stmt
appears in a STATEMENT_LIST that contains only that
stmt and some DEBUG_BEGIN_STMTs, without -g where the
STATEMENT_LIST wouldn't be present at all the resulting
expression wouldn't have TREE_SIDE_EFFECTS set, so make sure
to clear it even on the STATEMENT_LIST in such cases. */
for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
{
tree t = tsi_stmt (i);
if (TREE_CODE (t) != DEBUG_BEGIN_STMT && nondebug_stmts < 2)
nondebug_stmts++;
walk_tree_1 (tsi_stmt_ptr (i), func, data, NULL, lh);
if (TREE_CODE (t) != DEBUG_BEGIN_STMT
&& (nondebug_stmts > 1 || TREE_SIDE_EFFECTS (tsi_stmt (i))))
clear_side_effects = false;
}
if (clear_side_effects)
TREE_SIDE_EFFECTS (stmt) = 0;
*walk_subtrees = 0;
}
break;
default:
break;
}

30
gcc/cp/cp-gimplify.c
View File

@ -1464,35 +1464,6 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
walk_subtrees = 0;
break;
case STATEMENT_LIST:
if (TREE_SIDE_EFFECTS (stmt))
{
tree_stmt_iterator i;
int nondebug_stmts = 0;
bool clear_side_effects = true;
/* Genericization can clear TREE_SIDE_EFFECTS, e.g. when
transforming an IF_STMT into COND_EXPR. If such stmt
appears in a STATEMENT_LIST that contains only that
stmt and some DEBUG_BEGIN_STMTs, without -g where the
STATEMENT_LIST wouldn't be present at all the resulting
expression wouldn't have TREE_SIDE_EFFECTS set, so make sure
to clear it even on the STATEMENT_LIST in such cases. */
for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
{
tree t = tsi_stmt (i);
if (TREE_CODE (t) != DEBUG_BEGIN_STMT && nondebug_stmts < 2)
nondebug_stmts++;
cp_walk_tree (tsi_stmt_ptr (i), cp_genericize_r, data, NULL);
if (TREE_CODE (t) != DEBUG_BEGIN_STMT
&& (nondebug_stmts > 1 || TREE_SIDE_EFFECTS (tsi_stmt (i))))
clear_side_effects = false;
}
if (clear_side_effects)
TREE_SIDE_EFFECTS (stmt) = 0;
*walk_subtrees = 0;
}
break;
case OMP_DISTRIBUTE:
/* Need to explicitly instantiate copy ctors on class iterators of
composite distribute parallel for. */
@ -1566,6 +1537,7 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
case OMP_SIMD:
case OMP_LOOP:
case OACC_LOOP:
case STATEMENT_LIST:
/* These cases are handled by shared code. */
c_genericize_control_stmt (stmt_p, walk_subtrees, data,
cp_genericize_r, cp_walk_subtrees);

40
gcc/testsuite/gcc.dg/pr99230.c Normal file
View File

@ -0,0 +1,40 @@
/* PR debug/99230 */
/* { dg-do compile } */
/* { dg-options "-O2 --param logical-op-non-short-circuit=0 -fcompare-debug --param=jump-table-max-growth-ratio-for-speed=5000" } */
extern void fn2 (void);
extern void fn3 (int);
int a, b;
void
fn1 (void)
{
int c;
short d;
switch (a) {
case 22000:
fn2 ();
case 22300:
b = 0;
case 22600:
case 22601:
case 22900:
fn3 (1);
case 20100:
fn3 (2);
case 20200:
fn3 (3);
case 20300:
fn3 (4);
case 20400:
fn3 (5);
case 20310:
fn3 (4);
case 20410:
fn3 (5);
}
if (d || c) {
do
;
while (0);
}
}