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?
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
