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re PR tree-optimization/24931 (uninitialized structure member after assignment)

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PR 24931
        * tree-sra.c (struct sra_elt): Add all_no_warning.
        (struct sra_walk_fns) <use>: Add use_all argument.
        (sra_walk_expr): Pass it.
        (sra_walk_modify_expr): Likewise.
        (scalarize_ldst): Likewise.
        (scan_use): Update for new argument.
        (mark_no_warning): New.
        (scalarize_use): Use it.

From-SVN: r107271
This commit is contained in:
Richard Henderson 2005-11-20 16:51:39 -08:00 • committed by Richard Henderson
parent 6b6c5c5d68
commit d116ffa6c2
3 changed files with 68 additions and 9 deletions
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12
gcc/ChangeLog
View file

@ -1,3 +1,15 @@
2005-11-20 Richard Henderson <rth@redhat.com>
PR 24931
* tree-sra.c (struct sra_elt): Add all_no_warning.
(struct sra_walk_fns) <use>: Add use_all argument.
(sra_walk_expr): Pass it.
(sra_walk_modify_expr): Likewise.
(scalarize_ldst): Likewise.
(scan_use): Update for new argument.
(mark_no_warning): New.
(scalarize_use): Use it.
2005-11-20 Bernd Schmidt <bernd.schmidt@analog.com>
* expr.c (expand_expr_real): Use usmul_optab for widening

20
gcc/testsuite/gcc.dg/uninit-14.c Normal file
View file

@ -0,0 +1,20 @@
/* PR 24931 */
/* { dg-do compile } */
/* { dg-options "-O -Wuninitialized" } */
struct p {
short x, y;
};
struct s {
int i;
struct p p;
};
struct s f()
{
struct s s;
s.p = (struct p){};
s.i = (s.p.x || s.p.y);
return s;
}

45
gcc/tree-sra.c
View file

@ -127,6 +127,9 @@ struct sra_elt
should happen via memcpy and not per-element. */
bool use_block_copy;
/* True if everything under this element has been marked TREE_NO_WARNING. */
bool all_no_warning;
/* A flag for use with/after random access traversals. */
bool visited;
};
@ -598,9 +601,10 @@ struct sra_walk_fns
/* Invoked when ELT is required as a unit. Note that ELT might refer to
a leaf node, in which case this is a simple scalar reference. *EXPR_P
points to the location of the expression. IS_OUTPUT is true if this
is a left-hand-side reference. */
is a left-hand-side reference. USE_ALL is true if we saw something we
couldn't quite identify and had to force the use of the entire object. */
void (*use) (struct sra_elt *elt, tree *expr_p,
block_stmt_iterator *bsi, bool is_output);
block_stmt_iterator *bsi, bool is_output, bool use_all);
/* Invoked when we have a copy between two scalarizable references. */
void (*copy) (struct sra_elt *lhs_elt, struct sra_elt *rhs_elt,
@ -654,6 +658,7 @@ sra_walk_expr (tree *expr_p, block_stmt_iterator *bsi, bool is_output,
tree expr = *expr_p;
tree inner = expr;
bool disable_scalarization = false;
bool use_all_p = false;
/* We're looking to collect a reference expression between EXPR and INNER,
such that INNER is a scalarizable decl and all other nodes through EXPR
@ -674,7 +679,7 @@ sra_walk_expr (tree *expr_p, block_stmt_iterator *bsi, bool is_output,
if (disable_scalarization)
elt->cannot_scalarize = true;
else
fns->use (elt, expr_p, bsi, is_output);
fns->use (elt, expr_p, bsi, is_output, use_all_p);
}
return;
@ -742,6 +747,7 @@ sra_walk_expr (tree *expr_p, block_stmt_iterator *bsi, bool is_output,
use_all:
expr_p = &TREE_OPERAND (inner, 0);
inner = expr = *expr_p;
use_all_p = true;
break;
default:
@ -813,7 +819,7 @@ sra_walk_modify_expr (tree expr, block_stmt_iterator *bsi,
if (!rhs_elt->is_scalar)
fns->ldst (rhs_elt, lhs, bsi, false);
else
fns->use (rhs_elt, &TREE_OPERAND (expr, 1), bsi, false);
fns->use (rhs_elt, &TREE_OPERAND (expr, 1), bsi, false, false);
}
/* If it isn't scalarizable, there may be scalarizable variables within, so
@ -859,7 +865,7 @@ sra_walk_modify_expr (tree expr, block_stmt_iterator *bsi,
/* Otherwise we're being used in some context that requires the
aggregate to be seen as a whole. Invoke USE. */
else
fns->use (lhs_elt, &TREE_OPERAND (expr, 0), bsi, true);
fns->use (lhs_elt, &TREE_OPERAND (expr, 0), bsi, true, false);
}
/* Similarly to above, LHS_ELT being null only means that the LHS as a
@ -967,7 +973,7 @@ find_candidates_for_sra (void)
static void
scan_use (struct sra_elt *elt, tree *expr_p ATTRIBUTE_UNUSED,
block_stmt_iterator *bsi ATTRIBUTE_UNUSED,
bool is_output ATTRIBUTE_UNUSED)
bool is_output ATTRIBUTE_UNUSED, bool use_all ATTRIBUTE_UNUSED)
{
elt->n_uses += 1;
}
@ -1472,6 +1478,23 @@ mark_all_v_defs (tree list)
}
}
/* Mark every replacement under ELT with TREE_NO_WARNING. */
static void
mark_no_warning (struct sra_elt *elt)
{
if (!elt->all_no_warning)
{
if (elt->replacement)
TREE_NO_WARNING (elt->replacement) = 1;
else
{
struct sra_elt *c;
for (c = elt->children; c ; c = c->sibling)
mark_no_warning (c);
}
}
}
/* Build a single level component reference to ELT rooted at BASE. */
@ -1815,7 +1838,7 @@ sra_replace (block_stmt_iterator *bsi, tree list)
static void
scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
bool is_output)
bool is_output, bool use_all)
{
tree list = NULL, stmt = bsi_stmt (*bsi);
@ -1850,7 +1873,11 @@ scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
if (is_output)
sra_insert_after (bsi, list);
else
sra_insert_before (bsi, list);
{
sra_insert_before (bsi, list);
if (use_all)
mark_no_warning (elt);
}
}
}
@ -2015,7 +2042,7 @@ scalarize_ldst (struct sra_elt *elt, tree other,
{
/* Since ELT is not fully instantiated, we have to leave the
block copy in place. Treat this as a USE. */
scalarize_use (elt, NULL, bsi, is_output);
scalarize_use (elt, NULL, bsi, is_output, false);
}
else
{