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Avoid needless unsharing during constexpr evaluation (PR c++/70452)

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gcc/cp/ChangeLog:

	PR c++/70452
	* constexpr.c (find_constructor): New function.
	(unshare_constructor): New function.
	(cxx_eval_call_expression): Use unshare_constructor instead of
	unshare_expr.
	(find_array_ctor_elt): Likewise.
	(cxx_eval_vec_init_1): Likewise.
	(cxx_eval_store_expression): Likewise.
	(cxx_eval_constant_expression): Likewise.

From-SVN: r234810
This commit is contained in:
Patrick Palka 2016-04-07 16:12:05 +00:00
parent 9817ae350c
commit 0146e25f90
2 changed files with 44 additions and 8 deletions
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12
gcc/cp/ChangeLog
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@ -1,3 +1,15 @@
2016-04-07 Patrick Palka <ppalka@gcc.gnu.org>
PR c++/70452
* constexpr.c (find_constructor): New function.
(unshare_constructor): New function.
(cxx_eval_call_expression): Use unshare_constructor instead of
unshare_expr.
(find_array_ctor_elt): Likewise.
(cxx_eval_vec_init_1): Likewise.
(cxx_eval_store_expression): Likewise.
(cxx_eval_constant_expression): Likewise.
2016-04-06 Patrick Palka <ppalka@gcc.gnu.org>
PR c/70436

40
gcc/cp/constexpr.c
View file

@ -1151,6 +1151,30 @@ adjust_temp_type (tree type, tree temp)
return cp_fold_convert (type, temp);
}
/* Callback for walk_tree used by unshare_constructor. */
static tree
find_constructor (tree *tp, int *walk_subtrees, void *)
{
if (TYPE_P (*tp))
*walk_subtrees = 0;
if (TREE_CODE (*tp) == CONSTRUCTOR)
return *tp;
return NULL_TREE;
}
/* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a
subexpression, return an unshared copy of T. Otherwise return T. */
static tree
unshare_constructor (tree t)
{
tree ctor = walk_tree (&t, find_constructor, NULL, NULL);
if (ctor != NULL_TREE)
return unshare_expr (t);
return t;
}
/* Subroutine of cxx_eval_call_expression.
We are processing a call expression (either CALL_EXPR or
AGGR_INIT_EXPR) in the context of CTX. Evaluate
@ -1454,7 +1478,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
tree arg = TREE_VALUE (bound);
gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm));
/* Don't share a CONSTRUCTOR that might be changed. */
arg = unshare_expr (arg);
arg = unshare_constructor (arg);
ctx->values->put (remapped, arg);
bound = TREE_CHAIN (bound);
remapped = DECL_CHAIN (remapped);
@ -1534,7 +1558,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
}
pop_cx_call_context ();
return unshare_expr (result);
return unshare_constructor (result);
}
/* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */
@ -1880,7 +1904,7 @@ find_array_ctor_elt (tree ary, tree dindex, bool insert = false)
/* Append the element we want to insert. */
++middle;
e.index = dindex;
e.value = unshare_expr (elt.value);
e.value = unshare_constructor (elt.value);
vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e);
}
else
@ -1896,7 +1920,7 @@ find_array_ctor_elt (tree ary, tree dindex, bool insert = false)
e.index = hi;
else
e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi);
e.value = unshare_expr (elt.value);
e.value = unshare_constructor (elt.value);
vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle+1, e);
}
}
@ -2565,7 +2589,7 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
for (i = 1; i < max; ++i)
{
idx = build_int_cst (size_type_node, i);
CONSTRUCTOR_APPEND_ELT (*p, idx, unshare_expr (eltinit));
CONSTRUCTOR_APPEND_ELT (*p, idx, unshare_constructor (eltinit));
}
break;
}
@ -3113,7 +3137,7 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
init = cxx_eval_constant_expression (&new_ctx, init, false,
non_constant_p, overflow_p);
/* Don't share a CONSTRUCTOR that might be changed later. */
init = unshare_expr (init);
init = unshare_constructor (init);
if (target == object)
/* The hash table might have moved since the get earlier. */
valp = ctx->values->get (object);
@ -3565,7 +3589,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
false,
non_constant_p, overflow_p);
/* Don't share a CONSTRUCTOR that might be changed. */
init = unshare_expr (init);
init = unshare_constructor (init);
ctx->values->put (r, init);
}
else if (ctx == &new_ctx)
@ -3610,7 +3634,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
if (lval)
{
tree slot = TARGET_EXPR_SLOT (t);
r = unshare_expr (r);
r = unshare_constructor (r);
ctx->values->put (slot, r);
return slot;
}