On Thu, 31 May 2012, Richard Guenther wrote:
> On Wed, 30 May 2012, Richard Guenther wrote:
>
> >
> > The patch below extents memset recognition to cover a few more
> > non-byte-size store loops and all byte-size store loops. This exposes
> > issues with our builtins.exp testsuite which has custom memset
> > routines like
> >
> > void *
> > my_memset (void *d, int c, size_t n)
> > {
> > char *dst = (char *) d;
> > while (n--)
> > *dst++ = c;
> > return (char *) d;
> > }
> >
> > Now, for LTO we have papered over similar issues by attaching
> > the used attribute to the functions. But the general question is - when
> > can we be sure the function we are dealing with are not the actual
> > implementation for the builtin call we want to generate? A few
> > things come to my mind:
> >
> > 1) the function already calls the function we want to generate (well,
> > it might be a tail-recursive memset implementation ...)
> >
> > 2) the function availability is AVAIL_LOCAL
> >
> > 3) ... ?
> >
> > For sure 2) would work, but it would severely restrict the transform
> > (do we care?).
> >
> > We have a similar issue with sin/cos -> sincos transform and a
> > trivial sincos implementation.
> >
> > Any ideas?
> >
> > Bootstrapped (with memset recognition enabled by default) and tested
> > on x86_64-unknown-linux-gnu with the aforementioned issues.
>
> The following fixes it by simply always adding
> -fno-tree-loop-distribute-patterns to builtins.exp.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> If there are no further comments I'll go with the local advise from
> Micha who says "who cares".
Now done with the much simpler patch below (after all the loop
distribution TLC).
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2012-06-05 Richard Guenther <[email protected]>
PR tree-optimization/53081
* tree-loop-distribution.c (generate_memset_builtin): Handle all
kinds of byte-sized stores.
(classify_partition): Likewise.
(tree_loop_distribution): Adjust seed statements used for
!flag_tree_loop_distribution.
* gcc.dg/tree-ssa/ldist-19.c: New testcase.
* gcc.c-torture/execute/builtins/builtins.exp: Always pass
-fno-tree-loop-distribute-patterns.
Index: gcc/tree-loop-distribution.c
===================================================================
*** gcc/tree-loop-distribution.c.orig 2012-06-04 17:05:14.000000000 +0200
--- gcc/tree-loop-distribution.c 2012-06-04 17:32:38.829355831 +0200
*************** generate_memset_builtin (struct loop *lo
*** 332,337 ****
--- 332,338 ----
gimple_seq stmt_list = NULL, stmts;
struct data_reference *dr = XCNEW (struct data_reference);
location_t loc;
+ tree val;
stmt = partition->main_stmt;
loc = gimple_location (stmt);
*************** generate_memset_builtin (struct loop *lo
*** 364,376 ****
mem = force_gimple_operand (addr_base, &stmts, true, NULL);
gimple_seq_add_seq (&stmt_list, stmts);
fn = build_fold_addr_expr (builtin_decl_implicit (BUILT_IN_MEMSET));
! fn_call = gimple_build_call (fn, 3, mem, integer_zero_node, nb_bytes);
gimple_seq_add_stmt (&stmt_list, fn_call);
gsi_insert_seq_after (&gsi, stmt_list, GSI_CONTINUE_LINKING);
if (dump_file && (dump_flags & TDF_DETAILS))
! fprintf (dump_file, "generated memset zero\n");
}
/* Remove and destroy the loop LOOP. */
--- 365,408 ----
mem = force_gimple_operand (addr_base, &stmts, true, NULL);
gimple_seq_add_seq (&stmt_list, stmts);
+ /* This exactly matches the pattern recognition in classify_partition. */
+ val = gimple_assign_rhs1 (stmt);
+ if (integer_zerop (val)
+ || real_zerop (val)
+ || TREE_CODE (val) == CONSTRUCTOR)
+ val = integer_zero_node;
+ else if (integer_all_onesp (val))
+ val = build_int_cst (integer_type_node, -1);
+ else
+ {
+ if (TREE_CODE (val) == INTEGER_CST)
+ val = fold_convert (integer_type_node, val);
+ else if (!useless_type_conversion_p (integer_type_node, TREE_TYPE
(val)))
+ {
+ gimple cstmt;
+ tree tem = create_tmp_reg (integer_type_node, NULL);
+ tem = make_ssa_name (tem, NULL);
+ cstmt = gimple_build_assign_with_ops (NOP_EXPR, tem, val, NULL_TREE);
+ gimple_seq_add_stmt (&stmt_list, cstmt);
+ val = tem;
+ }
+ }
+
fn = build_fold_addr_expr (builtin_decl_implicit (BUILT_IN_MEMSET));
! fn_call = gimple_build_call (fn, 3, mem, val, nb_bytes);
gimple_seq_add_stmt (&stmt_list, fn_call);
gsi_insert_seq_after (&gsi, stmt_list, GSI_CONTINUE_LINKING);
if (dump_file && (dump_flags & TDF_DETAILS))
! {
! fprintf (dump_file, "generated memset");
! if (integer_zerop (val))
! fprintf (dump_file, " zero\n");
! else if (integer_all_onesp (val))
! fprintf (dump_file, " minus one\n");
! else
! fprintf (dump_file, "\n");
! }
}
/* Remove and destroy the loop LOOP. */
*************** classify_partition (loop_p loop, struct
*** 865,871 ****
return;
partition->main_stmt = stmt;
rhs = gimple_assign_rhs1 (stmt);
! if (!(integer_zerop (rhs) || real_zerop (rhs)))
return;
if (VEC_length (data_reference_p, RDG_DATAREFS (rdg, i)) != 1)
return;
--- 897,915 ----
return;
partition->main_stmt = stmt;
rhs = gimple_assign_rhs1 (stmt);
! if (!(integer_zerop (rhs)
! || integer_all_onesp (rhs)
! || real_zerop (rhs)
! || (TREE_CODE (rhs) == CONSTRUCTOR
! && !TREE_CLOBBER_P (rhs))
! || (INTEGRAL_TYPE_P (TREE_TYPE (rhs))
! && (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)))
! == TYPE_MODE (unsigned_char_type_node)))))
! return;
! if (TREE_CODE (rhs) == SSA_NAME
! && !SSA_NAME_IS_DEFAULT_DEF (rhs)
! && flow_bb_inside_loop_p
! (loop, gimple_bb (SSA_NAME_DEF_STMT (rhs))))
return;
if (VEC_length (data_reference_p, RDG_DATAREFS (rdg, i)) != 1)
return;
*************** tree_loop_distribution (void)
*** 1346,1354 ****
/* If we are only performing pattern detection restrict
what we try to distribute to stores from constants. */
! if (!flag_tree_loop_distribution
! && !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
! continue;
VEC_safe_push (gimple, heap, work_list, stmt);
}
--- 1390,1408 ----
/* If we are only performing pattern detection restrict
what we try to distribute to stores from constants. */
! if (!flag_tree_loop_distribution)
! {
! tree rhs = gimple_assign_rhs1 (stmt);
! if (!is_gimple_min_invariant (rhs)
! && TREE_CODE (rhs) != CONSTRUCTOR
! && TREE_CODE (rhs) != SSA_NAME)
! continue;
! if (TREE_CODE (rhs) == SSA_NAME
! && !SSA_NAME_IS_DEFAULT_DEF (rhs)
! && flow_bb_inside_loop_p
! (loop, gimple_bb (SSA_NAME_DEF_STMT (rhs))))
! continue;
! }
VEC_safe_push (gimple, heap, work_list, stmt);
}
Index: gcc/testsuite/gcc.dg/tree-ssa/ldist-19.c
===================================================================
*** /dev/null 1970-01-01 00:00:00.000000000 +0000
--- gcc/testsuite/gcc.dg/tree-ssa/ldist-19.c 2012-06-04 17:27:29.305366537
+0200
***************
*** 0 ****
--- 1,72 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O3 -fdump-tree-ldist-details" } */
+
+ struct Foo
+ {
+ char a;
+ };
+
+ struct Foo x[256];
+
+ static void __attribute__((noinline,noclone))
+ foo()
+ {
+ int i;
+ for (i = 0; i < 256; ++i)
+ x[i] = (struct Foo){};
+ }
+
+ static void __attribute__((noinline,noclone))
+ bar()
+ {
+ int i;
+ for (i = 0; i < 256; ++i)
+ x[i].a = 1;
+ }
+
+ static void __attribute__((noinline,noclone))
+ foobar(unsigned char c)
+ {
+ int i;
+ for (i = 0; i < 256; ++i)
+ x[i].a = c;
+ }
+
+ static void __attribute__((noinline,noclone))
+ foobar2(char c)
+ {
+ int i;
+ for (i = 0; i < 256; ++i)
+ x[i].a = c;
+ }
+
+ struct Baz
+ {
+ short a;
+ };
+
+ struct Baz y[256];
+
+ static void __attribute__((noinline,noclone))
+ baz()
+ {
+ int i;
+ for (i = 0; i < 256; ++i)
+ y[i].a = -1;
+ }
+
+ int main()
+ {
+ volatile int x;
+ foo();
+ bar();
+ foobar(x);
+ foobar2(x);
+ baz();
+ return 0;
+ }
+
+ /* { dg-final { scan-tree-dump-times "generated memset zero" 1 "ldist" } } */
+ /* { dg-final { scan-tree-dump-times "generated memset minus one" 1 "ldist" }
} */
+ /* { dg-final { scan-tree-dump-times "generated memset" 5 "ldist" } } */
+ /* { dg-final { cleanup-tree-dump "ldist" } } */
Index: gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
===================================================================
*** gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp.orig
2012-06-04 13:47:31.000000000 +0200
--- gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp 2012-06-04
17:06:46.662409562 +0200
*************** load_lib c-torture.exp
*** 37,43 ****
torture-init
set-torture-options $C_TORTURE_OPTIONS {{}} $LTO_TORTURE_OPTIONS
! set additional_flags ""
if [istarget "powerpc-*-darwin*"] {
lappend additional_flags "-Wl,-multiply_defined,suppress"
}
--- 37,43 ----
torture-init
set-torture-options $C_TORTURE_OPTIONS {{}} $LTO_TORTURE_OPTIONS
! set additional_flags "-fno-tree-loop-distribute-patterns"
if [istarget "powerpc-*-darwin*"] {
lappend additional_flags "-Wl,-multiply_defined,suppress"
}
