On Mon, 21 Jan 2019, Jakub Jelinek wrote:
> Hi!
>
> Apparently RTL DSE doesn't perform any kind of escape analysis for e.g.
> frame pointer related addresses, instead relies on TREE_ADDRESSABLE being
> set on MEM_EXPR VAR_DECLs if the address could leak to other functions.
>
> Since PR49454 expr.c contains code to force those to be addressable
> if they weren't addressable in GIMPLE, but it does so only before one of the
> 5 indirect emit_block_op_via_libcall callers, so it is done for memcpy, but
> not for memmove, or memcmp, or for memcpy expanded from within the i386
> backend's movmem etc.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
OK.
Richard.
> 2019-01-21 Jakub Jelinek <ja...@redhat.com>
>
> PR rtl-optimization/49429
> PR target/49454
> PR rtl-optimization/86334
> PR target/88906
> * expr.c (emit_block_move_hints): Move marking of MEM_EXPRs
> addressable from here...
> (emit_block_op_via_libcall): ... to here.
>
> * gcc.target/i386/pr86334.c: New test.
> * gcc.target/i386/pr88906.c: New test.
>
> --- gcc/expr.c.jj 2019-01-10 11:43:08.958466880 +0100
> +++ gcc/expr.c 2019-01-21 12:06:41.782406169 +0100
> @@ -1631,14 +1631,6 @@ emit_block_move_hints (rtx x, rtx y, rtx
> if (may_use_call < 0)
> return pc_rtx;
>
> - /* Since x and y are passed to a libcall, mark the corresponding
> - tree EXPR as addressable. */
> - tree y_expr = MEM_EXPR (y);
> - tree x_expr = MEM_EXPR (x);
> - if (y_expr)
> - mark_addressable (y_expr);
> - if (x_expr)
> - mark_addressable (x_expr);
> retval = emit_block_copy_via_libcall (x, y, size,
> method == BLOCK_OP_TAILCALL);
> }
> @@ -1884,6 +1876,15 @@ emit_block_op_via_libcall (enum built_in
> tree call_expr, dst_tree, src_tree, size_tree;
> machine_mode size_mode;
>
> + /* Since dst and src are passed to a libcall, mark the corresponding
> + tree EXPR as addressable. */
> + tree dst_expr = MEM_EXPR (dst);
> + tree src_expr = MEM_EXPR (src);
> + if (dst_expr)
> + mark_addressable (dst_expr);
> + if (src_expr)
> + mark_addressable (src_expr);
> +
> dst_addr = copy_addr_to_reg (XEXP (dst, 0));
> dst_addr = convert_memory_address (ptr_mode, dst_addr);
> dst_tree = make_tree (ptr_type_node, dst_addr);
> --- gcc/testsuite/gcc.target/i386/pr86334.c.jj 2019-01-21
> 17:52:04.408370956 +0100
> +++ gcc/testsuite/gcc.target/i386/pr86334.c 2019-01-21 17:52:58.504482908
> +0100
> @@ -0,0 +1,21 @@
> +/* PR rtl-optimization/86334 */
> +/* { dg-do run { target ia32 } } */
> +/* { dg-options "-O -march=i386 -mtune=athlon -minline-all-stringops
> -minline-stringops-dynamically -mmemcpy-strategy=libcall:-1:align -Wno-psabi"
> } */
> +
> +typedef int V __attribute__ ((vector_size (64)));
> +
> +static inline V
> +foo (V g)
> +{
> + g[0] = 4;
> + return g;
> +}
> +
> +int
> +main ()
> +{
> + V x = foo ((V) { });
> + if (x[0] != 4 || x[1] || x[2] || x[3] || x[4] || x[5] || x[6] || x[7])
> + __builtin_abort ();
> + return 0;
> +}
> --- gcc/testsuite/gcc.target/i386/pr88906.c.jj 2019-01-21
> 12:08:53.110252030 +0100
> +++ gcc/testsuite/gcc.target/i386/pr88906.c 2019-01-21 17:53:08.082325657
> +0100
> @@ -0,0 +1,21 @@
> +/* PR target/88906 */
> +/* { dg-do run { target ia32 } } */
> +/* { dg-options "-O -march=i386 -mtune=k6 -minline-all-stringops
> -minline-stringops-dynamically -mmemcpy-strategy=libcall:-1:align -Wno-psabi"
> } */
> +
> +typedef unsigned V __attribute__ ((vector_size (16)));
> +
> +static inline V
> +foo (V v)
> +{
> + __builtin_sub_overflow (0, 0, &v[0]);
> + return v;
> +}
> +
> +int
> +main ()
> +{
> + V v = foo ((V) { ~0 });
> + if (v[0] || v[1] || v[2] || v[3])
> + __builtin_abort ();
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
