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Recompute TYPE_MODE and DECL_MODE for aggregate type for acclerator.

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The patch streams out VOIDmode for aggregate types with offloading enabled,
and recomputes appropriate TYPE_MODE and DECL_MODE while streaming-in on accel
side. The rationale for this change is to avoid streaming out host-specific
modes that may be used for aggregate types, which may not be representable on
the accelerator. For eg, AArch64 uses OImode for ARRAY_TYPE whose size is 256-bits,
and nvptx doesn't have OImode, and thus ends up emitting an error from
lto_input_mode_table.

gcc/ChangeLog:
	* lto-streamer-in.cc: (lto_read_tree_1): Set DECL_MODE (expr) to
	TREE_TYPE (TYPE_MODE (expr)) if TREE_TYPE (expr) is aggregate type and
	offloading is enabled.
	* stor-layout.cc (layout_type): Move computation of mode for
	ARRAY_TYPE from ...
	(compute_array_mode): ... to here.
	* stor-layout.h (compute_array_mode): Declare.
	* tree-streamer-in.cc: Include stor-layout.h.
	(unpack_ts_common_value_fields): Call compute_array_mode if offloading
	is enabled.
	* tree-streamer-out.cc (pack_ts_fixed_cst_value_fields): Stream out
	VOIDmode if decl has aggregate type and offloading is enabled.
	(pack_ts_type_common_value_fields): Stream out VOIDmode for aggregate
	type if offloading is enabled.

Signed-off-by: Prathamesh Kulkarni <prathameshk@nvidia.com>
This commit is contained in:
Prathamesh Kulkarni 2024-08-22 19:25:20 +05:30
parent a025081991
commit 792adb8d22
5 changed files with 69 additions and 20 deletions
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9
gcc/lto-streamer-in.cc
View file

@ -1752,6 +1752,15 @@ lto_read_tree_1 (class lto_input_block *ib, class data_in *data_in, tree expr)
with -g1, see for example PR113488. */
else if (DECL_P (expr) && DECL_ABSTRACT_ORIGIN (expr) == expr)
DECL_ABSTRACT_ORIGIN (expr) = NULL_TREE;
#ifdef ACCEL_COMPILER
if ((VAR_P (expr)
|| TREE_CODE (expr) == PARM_DECL
|| TREE_CODE (expr) == FIELD_DECL)
&& AGGREGATE_TYPE_P (TREE_TYPE (expr))
&& DECL_MODE (expr) == VOIDmode)
SET_DECL_MODE (expr, TYPE_MODE (TREE_TYPE (expr)));
#endif
}
}

45
gcc/stor-layout.cc
View file

@ -2396,6 +2396,32 @@ finish_builtin_struct (tree type, const char *name, tree fields,
layout_decl (TYPE_NAME (type), 0);
}
/* Compute TYPE_MODE for TYPE (which is ARRAY_TYPE). */
void compute_array_mode (tree type)
{
gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
SET_TYPE_MODE (type, BLKmode);
if (TYPE_SIZE (type) != 0
&& ! targetm.member_type_forces_blk (type, VOIDmode)
/* BLKmode elements force BLKmode aggregate;
else extract/store fields may lose. */
&& (TYPE_MODE (TREE_TYPE (type)) != BLKmode
|| TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
{
SET_TYPE_MODE (type, mode_for_array (TREE_TYPE (type),
TYPE_SIZE (type)));
if (TYPE_MODE (type) != BLKmode
&& STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
&& TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
{
TYPE_NO_FORCE_BLK (type) = 1;
SET_TYPE_MODE (type, BLKmode);
}
}
}
/* Calculate the mode, size, and alignment for TYPE.
For an array type, calculate the element separation as well.
Record TYPE on the chain of permanent or temporary types
@ -2709,24 +2735,7 @@ layout_type (tree type)
align = MAX (align, BITS_PER_UNIT);
#endif
SET_TYPE_ALIGN (type, align);
SET_TYPE_MODE (type, BLKmode);
if (TYPE_SIZE (type) != 0
&& ! targetm.member_type_forces_blk (type, VOIDmode)
/* BLKmode elements force BLKmode aggregate;
else extract/store fields may lose. */
&& (TYPE_MODE (TREE_TYPE (type)) != BLKmode
|| TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
{
SET_TYPE_MODE (type, mode_for_array (TREE_TYPE (type),
TYPE_SIZE (type)));
if (TYPE_MODE (type) != BLKmode
&& STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
&& TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
{
TYPE_NO_FORCE_BLK (type) = 1;
SET_TYPE_MODE (type, BLKmode);
}
}
compute_array_mode (type);
if (AGGREGATE_TYPE_P (element))
TYPE_TYPELESS_STORAGE (type) = TYPE_TYPELESS_STORAGE (element);
/* When the element size is constant, check that it is at least as

1
gcc/stor-layout.h
View file

@ -34,6 +34,7 @@ extern tree rli_size_so_far (record_layout_info);
extern void normalize_rli (record_layout_info);
extern void place_field (record_layout_info, tree);
extern void compute_record_mode (tree);
extern void compute_array_mode (tree);
extern void finish_bitfield_layout (tree);
extern void finish_record_layout (record_layout_info, int);
extern void finalize_size_functions (void);

12
gcc/tree-streamer-in.cc
View file

@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see
#include "attribs.h"
#include "asan.h"
#include "opts.h"
#include "stor-layout.h"
/* Read a STRING_CST from the string table in DATA_IN using input
@ -395,6 +396,17 @@ unpack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
#ifdef ACCEL_COMPILER
if (TYPE_ALIGN (expr) > targetm.absolute_biggest_alignment)
SET_TYPE_ALIGN (expr, targetm.absolute_biggest_alignment);
/* Host streams out VOIDmode for aggregate type. */
if (AGGREGATE_TYPE_P (expr) && TYPE_MODE (expr) == VOIDmode)
{
if (TREE_CODE (expr) == ARRAY_TYPE)
compute_array_mode (expr);
else if (RECORD_OR_UNION_TYPE_P (expr))
compute_record_mode (expr);
else
gcc_unreachable ();
}
#endif
}

22
gcc/tree-streamer-out.cc
View file

@ -187,7 +187,17 @@ pack_ts_fixed_cst_value_fields (struct bitpack_d *bp, tree expr)
static void
pack_ts_decl_common_value_fields (struct bitpack_d *bp, tree expr)
{
bp_pack_machine_mode (bp, DECL_MODE (expr));
/* Similar to TYPE_MODE, avoid streaming out host-specific DECL_MODE
for aggregate type with offloading enabled, and while streaming-in
recompute appropriate DECL_MODE for accelerator. */
if (lto_stream_offload_p
&& (VAR_P (expr)
|| TREE_CODE (expr) == PARM_DECL
|| TREE_CODE (expr) == FIELD_DECL)
&& AGGREGATE_TYPE_P (TREE_TYPE (expr)))
bp_pack_machine_mode (bp, VOIDmode);
else
bp_pack_machine_mode (bp, DECL_MODE (expr));
bp_pack_value (bp, DECL_NONLOCAL (expr), 1);
bp_pack_value (bp, DECL_VIRTUAL_P (expr), 1);
bp_pack_value (bp, DECL_IGNORED_P (expr), 1);
@ -317,10 +327,18 @@ pack_ts_function_decl_value_fields (struct bitpack_d *bp, tree expr)
static void
pack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
{
/* For offloading, avoid streaming out TYPE_MODE for aggregate type since
it may be host-specific. For eg, aarch64 uses OImode for ARRAY_TYPE
whose size is 256-bits, which is not representable on accelerator.
Instead stream out VOIDmode, and while streaming-in, recompute
appropriate TYPE_MODE for accelerator. */
if (lto_stream_offload_p && AGGREGATE_TYPE_P (expr))
bp_pack_machine_mode (bp, VOIDmode);
/* for VECTOR_TYPE, TYPE_MODE reevaluates the mode using target_flags
not necessary valid in a global context.
Use the raw value previously set by layout_type. */
bp_pack_machine_mode (bp, TYPE_MODE_RAW (expr));
else
bp_pack_machine_mode (bp, TYPE_MODE_RAW (expr));
/* TYPE_NO_FORCE_BLK is private to stor-layout and need
no streaming. */
bp_pack_value (bp, TYPE_PACKED (expr), 1);