On April 23, 2020 8:19:55 PM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>In the recent get_narrower change, I wanted it to be efficient and
>avoid
>recursion if there are many nested COMPOUND_EXPRs. That builds the
>COMPOUND_EXPR nest with the right arguments, but as build2_loc computes
>some
>flags like TREE_SIDE_EFFECTS, TREE_CONSTANT and TREE_READONLY, when it
>is called with something that will not be the argument in the end,
>those
>flags are computed incorrectly.
>So, this patch instead uses an auto_vec and builds them in the reverse
>order
>so when they are built, they are built with the correct operands.
>
>Bootstrapped/regtested on powerpc64{,le}-linux, ok for trunk?
OK.
Richard.
>2020-04-23 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/94724
> * tree.c (get_narrower): Instead of creating COMPOUND_EXPRs
> temporarily with non-final second operand and updating it later,
> push COMPOUND_EXPRs into a vector and process it in reverse,
> creating COMPOUND_EXPRs with the final operands.
>
> * gcc.c-torture/execute/pr94724.c: New test.
>
>--- gcc/tree.c.jj 2020-04-04 09:14:29.808002636 +0200
>+++ gcc/tree.c 2020-04-23 11:07:34.003675831 +0200
>@@ -8881,18 +8881,22 @@ get_narrower (tree op, int *unsignedp_pt
>
> if (TREE_CODE (op) == COMPOUND_EXPR)
> {
>- while (TREE_CODE (op) == COMPOUND_EXPR)
>+ do
> op = TREE_OPERAND (op, 1);
>+ while (TREE_CODE (op) == COMPOUND_EXPR);
> tree ret = get_narrower (op, unsignedp_ptr);
> if (ret == op)
> return win;
>- op = win;
>- for (tree *p = &win; TREE_CODE (op) == COMPOUND_EXPR;
>- op = TREE_OPERAND (op, 1), p = &TREE_OPERAND (*p, 1))
>- *p = build2_loc (EXPR_LOCATION (op), COMPOUND_EXPR,
>- TREE_TYPE (ret), TREE_OPERAND (op, 0),
>- ret);
>- return win;
>+ auto_vec <tree, 16> v;
>+ unsigned int i;
>+ for (tree op = win; TREE_CODE (op) == COMPOUND_EXPR;
>+ op = TREE_OPERAND (op, 1))
>+ v.safe_push (op);
>+ FOR_EACH_VEC_ELT_REVERSE (v, i, op)
>+ ret = build2_loc (EXPR_LOCATION (op), COMPOUND_EXPR,
>+ TREE_TYPE (win), TREE_OPERAND (op, 0),
>+ ret);
>+ return ret;
> }
> while (TREE_CODE (op) == NOP_EXPR)
> {
>--- gcc/testsuite/gcc.c-torture/execute/pr94724.c.jj 2020-04-23
>11:11:52.470736940 +0200
>+++ gcc/testsuite/gcc.c-torture/execute/pr94724.c 2020-04-23
>11:14:27.999367103 +0200
>@@ -0,0 +1,12 @@
>+/* PR middle-end/94724 */
>+
>+short a, b;
>+
>+int
>+main ()
>+{
>+ (0, (0, (a = 0 >= 0, b))) != 53601;
>+ if (a != 1)
>+ __builtin_abort ();
>+ return 0;
>+}
>
> Jakub
