Ok.
On Mar 1, 2018 4:38 PM, "Marek Polacek" <pola...@redhat.com> wrote:
> On Thu, Mar 01, 2018 at 02:29:47PM -0500, Jason Merrill wrote:
> > I think this should happen in the block with maybe_constant_value;
> > cp_fold_rvalue doesn't do this.
>
> This, then:
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
>
> 2018-03-01 Marek Polacek <pola...@redhat.com>
>
> PR c++/84590
> * cp-gimplify.c (cp_fully_fold): Unwrap TARGET_EXPR or a
> CONSTRUCTOR
> wrapped in VIEW_CONVERT_EXPR.
>
> * c-c++-common/ubsan/shift-11.c: New test.
>
> diff --git gcc/cp/cp-gimplify.c gcc/cp/cp-gimplify.c
> index 55a9d278dbe..0ddd435454c 100644
> --- gcc/cp/cp-gimplify.c
> +++ gcc/cp/cp-gimplify.c
> @@ -2037,7 +2037,17 @@ cp_fully_fold (tree x)
> /* FIXME cp_fold ought to be a superset of maybe_constant_value so we
> don't
> have to call both. */
> if (cxx_dialect >= cxx11)
> - x = maybe_constant_value (x);
> + {
> + x = maybe_constant_value (x);
> + /* Sometimes we are given a CONSTRUCTOR but the call above wraps it
> into
> + a TARGET_EXPR; undo that here. */
> + if (TREE_CODE (x) == TARGET_EXPR)
> + x = TARGET_EXPR_INITIAL (x);
> + else if (TREE_CODE (x) == VIEW_CONVERT_EXPR
> + && TREE_CODE (TREE_OPERAND (x, 0)) == CONSTRUCTOR
> + && TREE_TYPE (TREE_OPERAND (x, 0)) == TREE_TYPE (x))
> + x = TREE_OPERAND (x, 0);
> + }
> return cp_fold_rvalue (x);
> }
>
> diff --git gcc/testsuite/c-c++-common/ubsan/shift-11.c
> gcc/testsuite/c-c++-common/ubsan/shift-11.c
> index e69de29bb2d..03a72e217a2 100644
> --- gcc/testsuite/c-c++-common/ubsan/shift-11.c
> +++ gcc/testsuite/c-c++-common/ubsan/shift-11.c
> @@ -0,0 +1,13 @@
> +/* PR c++/84590 */
> +/* { dg-do compile } */
> +/* { dg-options "-fsanitize=shift" } */
> +
> +struct S {
> + int b;
> +};
> +
> +void
> +fn (void)
> +{
> + struct S c1 = { 1 << -1 }; /* { dg-warning "left shift" } */
> +}
>
> Marek
>
