https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40635
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2019-02-24 00:00:00 |2021-3-25
Known to fail|9.0 |10.2.0, 11.0, 9.3.0
--- Comment #13 from Martin Sebor <msebor at gcc dot gnu.org> ---
I think the reason why the location for the last PHI argument isn't set is
because the argument is itself a PHI whose arguments have different locations:
<bb 8> [local count: 1073741824]:
# _16 = PHI <[pr40635.c:21:20] -1(13), [pr40635.c:19:15] s42_9(7),
[pr40635.c:28:16] -1(15), s42_21(9)>
[pr40635.c:37:5] foo ();
[pr40635.c:38:8] _28 = _16 < 0;
[pr40635.c:38:8] _5 = (int) _28;
[pr40635.c:38:8] _4 = -_5;
return _4;
<bb 12> [local count: 39298952]:
<bb 9> [local count: 383953502]:
# s42_21 = PHI <[pr40635.c:13:9] s42_18(D)(12), [pr40635.c:19:15] s42_9(14)>
goto <bb 8>; [100.00%]
}
Even if -Wuninitialized is changed to extract the location from the
uninitialized argument to s42_21(9), it doesn't use it because it prefers to
use the location of the statement where the variable us used. -Wuninitialized
usually prints a note pointing to the uninitialized variable but it has the
code below that guards is:
if (xloc.file != floc.file
|| linemap_location_before_p (line_table, location, cfun_loc)
|| linemap_location_before_p (line_table, cfun->function_end_locus,
location))
inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
Because the location of the variable is in a different function than the
current one the note isn't printed. The patch below removes this IMO pointless
test and improves the output a bit:
pr40635.c:38:8: warning: ‘s42’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
38 | if (sockt_rd < 0)
| ^
pr40635.c:13:9: note: ‘s42’ was declared here
13 | int s42, x;
| ^~~
diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c
index 0800f596ab1..a578a596fee 100644
--- a/gcc/tree-ssa-uninit.c
+++ b/gcc/tree-ssa-uninit.c
@@ -126,8 +126,6 @@ warn_uninit (enum opt_code wc, tree t, tree expr, tree var,
const char *gmsgid, void *data, location_t phiarg_loc)
{
gimple *context = (gimple *) data;
- location_t location, cfun_loc;
- expanded_location xloc, floc;
/* Ignore COMPLEX_EXPR as initializing only a part of a complex
turns in a COMPLEX_EXPR with the not initialized part being
@@ -170,6 +168,7 @@ warn_uninit (enum opt_code wc, tree t, tree expr, tree var,
|| TREE_NO_WARNING (expr))
return;
+ location_t location;
if (context != NULL && gimple_has_location (context))
location = gimple_location (context);
else if (phiarg_loc != UNKNOWN_LOCATION)
@@ -178,9 +177,7 @@ warn_uninit (enum opt_code wc, tree t, tree expr, tree var,
location = DECL_SOURCE_LOCATION (var);
location = linemap_resolve_location (line_table, location,
LRK_SPELLING_LOCATION, NULL);
- cfun_loc = DECL_SOURCE_LOCATION (cfun->decl);
- xloc = expand_location (location);
- floc = expand_location (cfun_loc);
+
auto_diagnostic_group d;
if (warning_at (location, wc, gmsgid, expr))
{
@@ -188,11 +185,7 @@ warn_uninit (enum opt_code wc, tree t, tree expr, tree
var,
if (location == DECL_SOURCE_LOCATION (var))
return;
- if (xloc.file != floc.file
- || linemap_location_before_p (line_table, location, cfun_loc)
- || linemap_location_before_p (line_table, cfun->function_end_locus,
- location))
- inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
+ inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
}
}
