+2011-07-27 Aldy Hernandez <aldyh@redhat.com>
+
+ * params.h (ALLOW_STORE_DATA_RACES): New.
+ * params.def (PARAM_ALLOW_STORE_DATA_RACES): New.
+ * Makefile.in (expr.o): Depend on PARAMS_H.
+ * machmode.h (get_best_mode): Add argument.
+ * fold-const.c (optimize_bit_field_compare): Add argument to
+ get_best_mode.
+ (fold_truthop): Same.
+ * ifcvt.c (noce_emit_move_insn): Add argument to store_bit_field.
+ * expr.c (emit_group_store): Same.
+ (copy_blkmode_from_reg): Same.
+ (write_complex_part): Same.
+ (optimize_bitfield_assignment_op): Add argument.
+ Add argument to get_best_mode.
+ (get_bit_range): New.
+ (expand_assignment): Calculate maxbits and pass it down
+ accordingly.
+ (store_field): New argument.
+ (expand_expr_real_2): New argument to store_field.
+ Include params.h.
+ * expr.h (store_bit_field): New argument.
+ * stor-layout.c (get_best_mode): Restrict mode expansion by taking
+ into account maxbits.
+ * calls.c (store_unaligned_arguments_into_pseudos): New argument
+ to store_bit_field.
+ * expmed.c (store_bit_field_1): New argument. Use it.
+ (store_bit_field): Same.
+ (store_fixed_bit_field): Same.
+ (store_split_bit_field): Same.
+ (extract_bit_field_1): Pass new argument to get_best_mode.
+ (extract_bit_field): Same.
+ * stmt.c (store_bit_field): Pass new argument to store_bit_field.
+ * doc/invoke.texi: Document parameter allow-store-data-races.
+
2011-07-27 Jakub Jelinek <jakub@redhat.com>
* dwarf2out.c (gen_producer_string): Ignore also -fverbose-asm
reload.h langhooks.h intl.h $(TM_P_H) $(TARGET_H) \
tree-iterator.h gt-expr.h $(MACHMODE_H) $(TIMEVAR_H) $(TREE_FLOW_H) \
$(TREE_PASS_H) $(DF_H) $(DIAGNOSTIC_H) vecprim.h $(SSAEXPAND_H) \
- $(COMMON_TARGET_H)
+ $(PARAMS_H) $(COMMON_TARGET_H)
dojump.o : dojump.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) \
$(FLAGS_H) $(FUNCTION_H) $(EXPR_H) $(OPTABS_H) $(INSN_ATTR_H) insn-config.h \
langhooks.h $(GGC_H) gt-dojump.h vecprim.h $(BASIC_BLOCK_H) output.h
emit_move_insn (reg, const0_rtx);
bytes -= bitsize / BITS_PER_UNIT;
- store_bit_field (reg, bitsize, endian_correction, word_mode,
- word);
+ store_bit_field (reg, bitsize, endian_correction, 0, 0,
+ word_mode, word);
}
}
}
if either vectorization (@option{-ftree-vectorize}) or if-conversion
(@option{-ftree-loop-if-convert}) is disabled. The default is 2.
+@item allow-store-data-races
+Allow optimizers to introduce new data races on stores.
+Set to 1 to allow, otherwise to 0. This option is enabled by default
+unless implicitly set by the @option{-fmemory-model=} option.
+
@item case-values-threshold
The smallest number of different values for which it is best to use a
jump-table instead of a tree of conditional branches. If the value is
static void store_fixed_bit_field (rtx, unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT,
- unsigned HOST_WIDE_INT, rtx);
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ rtx);
static void store_split_bit_field (rtx, unsigned HOST_WIDE_INT,
- unsigned HOST_WIDE_INT, rtx);
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ rtx);
static rtx extract_fixed_bit_field (enum machine_mode, rtx,
unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT,
static bool
store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
- unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode,
+ unsigned HOST_WIDE_INT bitnum,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
+ enum machine_mode fieldmode,
rtx value, bool fallback_p)
{
unsigned int unit
/* We may be accessing data outside the field, which means
we can alias adjacent data. */
+ /* ?? not always for C++0x memory model ?? */
if (MEM_P (op0))
{
op0 = shallow_copy_rtx (op0);
if (!store_bit_field_1 (op0, MIN (BITS_PER_WORD,
bitsize - i * BITS_PER_WORD),
- bitnum + bit_offset, word_mode,
+ bitnum + bit_offset,
+ bitregion_start, bitregion_end,
+ word_mode,
value_word, fallback_p))
{
delete_insns_since (last);
if (HAVE_insv && MEM_P (op0))
{
enum machine_mode bestmode;
+ unsigned HOST_WIDE_INT maxbits = MAX_FIXED_MODE_SIZE;
+
+ if (bitregion_end)
+ maxbits = bitregion_end - bitregion_start + 1;
/* Get the mode to use for inserting into this field. If OP0 is
BLKmode, get the smallest mode consistent with the alignment. If
mode. Otherwise, use the smallest mode containing the field. */
if (GET_MODE (op0) == BLKmode
+ || GET_MODE_BITSIZE (GET_MODE (op0)) > maxbits
|| (op_mode != MAX_MACHINE_MODE
&& GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (op_mode)))
- bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0),
+ bestmode = get_best_mode (bitsize, bitnum,
+ bitregion_start, bitregion_end,
+ MEM_ALIGN (op0),
(op_mode == MAX_MACHINE_MODE
? VOIDmode : op_mode),
MEM_VOLATILE_P (op0));
the unit. */
tempreg = copy_to_reg (xop0);
if (store_bit_field_1 (tempreg, bitsize, xbitpos,
+ bitregion_start, bitregion_end,
fieldmode, orig_value, false))
{
emit_move_insn (xop0, tempreg);
if (!fallback_p)
return false;
- store_fixed_bit_field (op0, offset, bitsize, bitpos, value);
+ store_fixed_bit_field (op0, offset, bitsize, bitpos,
+ bitregion_start, bitregion_end, value);
return true;
}
/* Generate code to store value from rtx VALUE
into a bit-field within structure STR_RTX
containing BITSIZE bits starting at bit BITNUM.
+
+ BITREGION_START is bitpos of the first bitfield in this region.
+ BITREGION_END is the bitpos of the ending bitfield in this region.
+ These two fields are 0, if the C++ memory model does not apply,
+ or we are not interested in keeping track of bitfield regions.
+
FIELDMODE is the machine-mode of the FIELD_DECL node for this field. */
void
store_bit_field (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
- unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode,
+ unsigned HOST_WIDE_INT bitnum,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
+ enum machine_mode fieldmode,
rtx value)
{
- if (!store_bit_field_1 (str_rtx, bitsize, bitnum, fieldmode, value, true))
+ /* Under the C++0x memory model, we must not touch bits outside the
+ bit region. Adjust the address to start at the beginning of the
+ bit region. */
+ if (MEM_P (str_rtx)
+ && bitregion_start > 0)
+ {
+ enum machine_mode bestmode;
+ enum machine_mode op_mode;
+ unsigned HOST_WIDE_INT offset;
+
+ op_mode = mode_for_extraction (EP_insv, 3);
+ if (op_mode == MAX_MACHINE_MODE)
+ op_mode = VOIDmode;
+
+ offset = bitregion_start / BITS_PER_UNIT;
+ bitnum -= bitregion_start;
+ bitregion_end -= bitregion_start;
+ bitregion_start = 0;
+ bestmode = get_best_mode (bitsize, bitnum,
+ bitregion_start, bitregion_end,
+ MEM_ALIGN (str_rtx),
+ op_mode,
+ MEM_VOLATILE_P (str_rtx));
+ str_rtx = adjust_address (str_rtx, bestmode, offset);
+ }
+
+ if (!store_bit_field_1 (str_rtx, bitsize, bitnum,
+ bitregion_start, bitregion_end,
+ fieldmode, value, true))
gcc_unreachable ();
}
\f
static void
store_fixed_bit_field (rtx op0, unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT bitsize,
- unsigned HOST_WIDE_INT bitpos, rtx value)
+ unsigned HOST_WIDE_INT bitpos,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
+ rtx value)
{
enum machine_mode mode;
unsigned int total_bits = BITS_PER_WORD;
/* Special treatment for a bit field split across two registers. */
if (bitsize + bitpos > BITS_PER_WORD)
{
- store_split_bit_field (op0, bitsize, bitpos, value);
+ store_split_bit_field (op0, bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ value);
return;
}
}
else
{
+ unsigned HOST_WIDE_INT maxbits = MAX_FIXED_MODE_SIZE;
+
+ if (bitregion_end)
+ maxbits = bitregion_end - bitregion_start + 1;
+
/* Get the proper mode to use for this field. We want a mode that
includes the entire field. If such a mode would be larger than
a word, we won't be doing the extraction the normal way.
if (MEM_VOLATILE_P (op0)
&& GET_MODE_BITSIZE (GET_MODE (op0)) > 0
+ && GET_MODE_BITSIZE (GET_MODE (op0)) <= maxbits
&& flag_strict_volatile_bitfields > 0)
mode = GET_MODE (op0);
else
mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
+ bitregion_start, bitregion_end,
MEM_ALIGN (op0), mode, MEM_VOLATILE_P (op0));
if (mode == VOIDmode)
/* The only way this should occur is if the field spans word
boundaries. */
store_split_bit_field (op0, bitsize, bitpos + offset * BITS_PER_UNIT,
- value);
+ bitregion_start, bitregion_end, value);
return;
}
static void
store_split_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize,
- unsigned HOST_WIDE_INT bitpos, rtx value)
+ unsigned HOST_WIDE_INT bitpos,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
+ rtx value)
{
unsigned int unit;
unsigned int bitsdone = 0;
it is just an out-of-bounds access. Ignore it. */
if (word != const0_rtx)
store_fixed_bit_field (word, offset * unit / BITS_PER_UNIT, thissize,
- thispos, part);
+ thispos, bitregion_start, bitregion_end, part);
bitsdone += thissize;
}
}
if (GET_MODE (op0) == BLKmode
|| (ext_mode != MAX_MACHINE_MODE
&& GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (ext_mode)))
- bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0),
+ bestmode = get_best_mode (bitsize, bitnum, 0, 0, MEM_ALIGN (op0),
(ext_mode == MAX_MACHINE_MODE
? VOIDmode : ext_mode),
MEM_VOLATILE_P (op0));
mode = tmode;
}
else
- mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
+ mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, 0, 0,
MEM_ALIGN (op0), word_mode, MEM_VOLATILE_P (op0));
if (mode == VOIDmode)
#include "diagnostic.h"
#include "ssaexpand.h"
#include "target-globals.h"
+#include "params.h"
/* Decide whether a function's arguments should be processed
from first to last or from last to first.
HOST_WIDE_INT, enum machine_mode,
tree, tree, int, alias_set_type);
static void store_constructor (tree, rtx, int, HOST_WIDE_INT);
-static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT, enum machine_mode,
+static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT,
+ enum machine_mode,
tree, tree, alias_set_type, bool);
static unsigned HOST_WIDE_INT highest_pow2_factor_for_target (const_tree, const_tree);
emit_move_insn (adjust_address (dest, mode, bytepos), tmps[i]);
else
store_bit_field (dest, bytelen * BITS_PER_UNIT, bytepos * BITS_PER_UNIT,
- mode, tmps[i]);
+ 0, 0, mode, tmps[i]);
}
/* Copy from the pseudo into the (probable) hard reg. */
/* Use xbitpos for the source extraction (right justified) and
bitpos for the destination store (left justified). */
- store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, copy_mode,
+ store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, 0, 0, copy_mode,
extract_bit_field (src, bitsize,
xbitpos % BITS_PER_WORD, 1, false,
NULL_RTX, copy_mode, copy_mode));
gcc_assert (MEM_P (cplx) && ibitsize < BITS_PER_WORD);
}
- store_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0, imode, val);
+ store_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0, 0, 0, imode, val);
}
/* Extract one of the components of the complex value CPLX. Extract the
static bool
optimize_bitfield_assignment_op (unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitpos,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
enum machine_mode mode1, rtx str_rtx,
tree to, tree src)
{
if (str_bitsize == 0 || str_bitsize > BITS_PER_WORD)
str_mode = word_mode;
str_mode = get_best_mode (bitsize, bitpos,
+ bitregion_start, bitregion_end,
MEM_ALIGN (str_rtx), str_mode, 0);
if (str_mode == VOIDmode)
return false;
return false;
}
+/* In the C++ memory model, consecutive bit fields in a structure are
+ considered one memory location.
+
+ Given a COMPONENT_REF, this function returns the bit range of
+ consecutive bits in which this COMPONENT_REF belongs in. The
+ values are returned in *BITSTART and *BITEND. If either the C++
+ memory model is not activated, or this memory access is not thread
+ visible, 0 is returned in *BITSTART and *BITEND.
+
+ EXP is the COMPONENT_REF.
+ INNERDECL is the actual object being referenced.
+ BITPOS is the position in bits where the bit starts within the structure.
+ BITSIZE is size in bits of the field being referenced in EXP.
+
+ For example, while storing into FOO.A here...
+
+ struct {
+ BIT 0:
+ unsigned int a : 4;
+ unsigned int b : 1;
+ BIT 8:
+ unsigned char c;
+ unsigned int d : 6;
+ } foo;
+
+ ...we are not allowed to store past <b>, so for the layout above, a
+ range of 0..7 (because no one cares if we store into the
+ padding). */
+
+static void
+get_bit_range (unsigned HOST_WIDE_INT *bitstart,
+ unsigned HOST_WIDE_INT *bitend,
+ tree exp, tree innerdecl,
+ HOST_WIDE_INT bitpos, HOST_WIDE_INT bitsize)
+{
+ tree field, record_type, fld;
+ bool found_field = false;
+ bool prev_field_is_bitfield;
+
+ gcc_assert (TREE_CODE (exp) == COMPONENT_REF);
+
+ /* If other threads can't see this value, no need to restrict stores. */
+ if (ALLOW_STORE_DATA_RACES
+ || (!ptr_deref_may_alias_global_p (innerdecl)
+ && (DECL_THREAD_LOCAL_P (innerdecl)
+ || !TREE_STATIC (innerdecl))))
+ {
+ *bitstart = *bitend = 0;
+ return;
+ }
+
+ /* Bit field we're storing into. */
+ field = TREE_OPERAND (exp, 1);
+ record_type = DECL_FIELD_CONTEXT (field);
+
+ /* Count the contiguous bitfields for the memory location that
+ contains FIELD. */
+ *bitstart = 0;
+ prev_field_is_bitfield = true;
+ for (fld = TYPE_FIELDS (record_type); fld; fld = DECL_CHAIN (fld))
+ {
+ tree t, offset;
+ enum machine_mode mode;
+ int unsignedp, volatilep;
+
+ if (TREE_CODE (fld) != FIELD_DECL)
+ continue;
+
+ t = build3 (COMPONENT_REF, TREE_TYPE (exp),
+ unshare_expr (TREE_OPERAND (exp, 0)),
+ fld, NULL_TREE);
+ get_inner_reference (t, &bitsize, &bitpos, &offset,
+ &mode, &unsignedp, &volatilep, true);
+
+ if (field == fld)
+ found_field = true;
+
+ if (DECL_BIT_FIELD_TYPE (fld) && bitsize > 0)
+ {
+ if (prev_field_is_bitfield == false)
+ {
+ *bitstart = bitpos;
+ prev_field_is_bitfield = true;
+ }
+ }
+ else
+ {
+ prev_field_is_bitfield = false;
+ if (found_field)
+ break;
+ }
+ }
+ gcc_assert (found_field);
+
+ if (fld)
+ {
+ /* We found the end of the bit field sequence. Include the
+ padding up to the next field and be done. */
+ *bitend = bitpos - 1;
+ }
+ else
+ {
+ /* If this is the last element in the structure, include the padding
+ at the end of structure. */
+ *bitend = TREE_INT_CST_LOW (TYPE_SIZE (record_type)) - 1;
+ }
+}
/* Expand an assignment that stores the value of FROM into TO. If NONTEMPORAL
is true, try generating a nontemporal store. */
{
enum machine_mode mode1;
HOST_WIDE_INT bitsize, bitpos;
+ unsigned HOST_WIDE_INT bitregion_start = 0;
+ unsigned HOST_WIDE_INT bitregion_end = 0;
tree offset;
int unsignedp;
int volatilep = 0;
tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1,
&unsignedp, &volatilep, true);
+ if (TREE_CODE (to) == COMPONENT_REF
+ && DECL_BIT_FIELD_TYPE (TREE_OPERAND (to, 1)))
+ get_bit_range (&bitregion_start, &bitregion_end,
+ to, tem, bitpos, bitsize);
+
/* If we are going to use store_bit_field and extract_bit_field,
make sure to_rtx will be safe for multiple use. */
nontemporal);
else if (bitpos + bitsize <= mode_bitsize / 2)
result = store_field (XEXP (to_rtx, 0), bitsize, bitpos,
+ bitregion_start, bitregion_end,
mode1, from, TREE_TYPE (tem),
get_alias_set (to), nontemporal);
else if (bitpos >= mode_bitsize / 2)
result = store_field (XEXP (to_rtx, 1), bitsize,
- bitpos - mode_bitsize / 2, mode1, from,
+ bitpos - mode_bitsize / 2,
+ bitregion_start, bitregion_end,
+ mode1, from,
TREE_TYPE (tem), get_alias_set (to),
nontemporal);
else if (bitpos == 0 && bitsize == mode_bitsize)
0);
write_complex_part (temp, XEXP (to_rtx, 0), false);
write_complex_part (temp, XEXP (to_rtx, 1), true);
- result = store_field (temp, bitsize, bitpos, mode1, from,
+ result = store_field (temp, bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ mode1, from,
TREE_TYPE (tem), get_alias_set (to),
nontemporal);
emit_move_insn (XEXP (to_rtx, 0), read_complex_part (temp, false));
MEM_KEEP_ALIAS_SET_P (to_rtx) = 1;
}
- if (optimize_bitfield_assignment_op (bitsize, bitpos, mode1,
+ if (optimize_bitfield_assignment_op (bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ mode1,
to_rtx, to, from))
result = NULL;
else
- result = store_field (to_rtx, bitsize, bitpos, mode1, from,
+ result = store_field (to_rtx, bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ mode1, from,
TREE_TYPE (tem), get_alias_set (to),
nontemporal);
}
: BLOCK_OP_NORMAL));
else if (GET_MODE (target) == BLKmode)
store_bit_field (target, INTVAL (expr_size (exp)) * BITS_PER_UNIT,
- 0, GET_MODE (temp), temp);
+ 0, 0, 0, GET_MODE (temp), temp);
else
convert_move (target, temp, unsignedp);
}
store_constructor (exp, target, cleared, bitsize / BITS_PER_UNIT);
}
else
- store_field (target, bitsize, bitpos, mode, exp, type, alias_set, false);
+ store_field (target, bitsize, bitpos, 0, 0, mode, exp, type, alias_set,
+ false);
}
/* Store the value of constructor EXP into the rtx TARGET.
BITSIZE bits, starting BITPOS bits from the start of TARGET.
If MODE is VOIDmode, it means that we are storing into a bit-field.
+ BITREGION_START is bitpos of the first bitfield in this region.
+ BITREGION_END is the bitpos of the ending bitfield in this region.
+ These two fields are 0, if the C++ memory model does not apply,
+ or we are not interested in keeping track of bitfield regions.
+
Always return const0_rtx unless we have something particular to
return.
static rtx
store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
enum machine_mode mode, tree exp, tree type,
alias_set_type alias_set, bool nontemporal)
{
if (bitsize != (HOST_WIDE_INT) GET_MODE_BITSIZE (GET_MODE (target)))
emit_move_insn (object, target);
- store_field (blk_object, bitsize, bitpos, mode, exp, type, alias_set,
- nontemporal);
+ store_field (blk_object, bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ mode, exp, type, alias_set, nontemporal);
emit_move_insn (target, object);
}
/* Store the value in the bitfield. */
- store_bit_field (target, bitsize, bitpos, mode, temp);
+ store_bit_field (target, bitsize, bitpos,
+ bitregion_start, bitregion_end,
+ mode, temp);
return const0_rtx;
}
(treeop0))
* BITS_PER_UNIT),
(HOST_WIDE_INT) GET_MODE_BITSIZE (mode)),
- 0, TYPE_MODE (valtype), treeop0,
+ 0, 0, 0, TYPE_MODE (valtype), treeop0,
type, 0, false);
}
mode_for_extraction (enum extraction_pattern, int);
extern void store_bit_field (rtx, unsigned HOST_WIDE_INT,
- unsigned HOST_WIDE_INT, enum machine_mode, rtx);
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ enum machine_mode, rtx);
extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT, int, bool, rtx,
enum machine_mode, enum machine_mode);
&& flag_strict_volatile_bitfields > 0)
nmode = lmode;
else
- nmode = get_best_mode (lbitsize, lbitpos,
+ nmode = get_best_mode (lbitsize, lbitpos, 0, 0,
const_p ? TYPE_ALIGN (TREE_TYPE (linner))
: MIN (TYPE_ALIGN (TREE_TYPE (linner)),
TYPE_ALIGN (TREE_TYPE (rinner))),
to be relative to a field of that size. */
first_bit = MIN (ll_bitpos, rl_bitpos);
end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
- lnmode = get_best_mode (end_bit - first_bit, first_bit,
+ lnmode = get_best_mode (end_bit - first_bit, first_bit, 0, 0,
TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
volatilep);
if (lnmode == VOIDmode)
first_bit = MIN (lr_bitpos, rr_bitpos);
end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
- rnmode = get_best_mode (end_bit - first_bit, first_bit,
+ rnmode = get_best_mode (end_bit - first_bit, first_bit, 0, 0,
TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
volatilep);
if (rnmode == VOIDmode)
}
gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
- store_bit_field (op, size, start, GET_MODE (x), y);
+ store_bit_field (op, size, start, 0, 0, GET_MODE (x), y);
return;
}
inner = XEXP (outer, 0);
outmode = GET_MODE (outer);
bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
- store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y);
+ store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos,
+ 0, 0, outmode, y);
}
/* Return sequence of instructions generated by if conversion. This
/* Find the best mode to use to access a bit field. */
-extern enum machine_mode get_best_mode (int, int, unsigned int,
+extern enum machine_mode get_best_mode (int, int,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT,
+ unsigned int,
enum machine_mode, int);
/* Determine alignment, 1<=result<=BIGGEST_ALIGNMENT. */
"if 0, use the default for the machine",
0, 0, 0)
+/* Data race flags for C++0x memory model compliance. */
+DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
+ "allow-store-data-races",
+ "Allow new data races on stores to be introduced",
+ 1, 0, 1)
+
/*
Local variables:
PARAM_VALUE (PARAM_MIN_NONDEBUG_INSN_UID)
#define MAX_STORES_TO_SINK \
PARAM_VALUE (PARAM_MAX_STORES_TO_SINK)
+#define ALLOW_STORE_DATA_RACES \
+ PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES)
#endif /* ! GCC_PARAMS_H */
/* Use bitpos for the source extraction (left justified) and
xbitpos for the destination store (right justified). */
- store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
+ store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD,
+ 0, 0, word_mode,
extract_bit_field (src, bitsize,
bitpos % BITS_PER_WORD, 1, false,
NULL_RTX, word_mode, word_mode));
/* Find the best machine mode to use when referencing a bit field of length
BITSIZE bits starting at BITPOS.
+ BITREGION_START is the bit position of the first bit in this
+ sequence of bit fields. BITREGION_END is the last bit in this
+ sequence. If these two fields are non-zero, we should restrict the
+ memory access to a maximum sized chunk of
+ BITREGION_END - BITREGION_START + 1. Otherwise, we are allowed to touch
+ any adjacent non bit-fields.
+
The underlying object is known to be aligned to a boundary of ALIGN bits.
If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
larger than LARGEST_MODE (usually SImode).
decide which of the above modes should be used. */
enum machine_mode
-get_best_mode (int bitsize, int bitpos, unsigned int align,
+get_best_mode (int bitsize, int bitpos,
+ unsigned HOST_WIDE_INT bitregion_start,
+ unsigned HOST_WIDE_INT bitregion_end,
+ unsigned int align,
enum machine_mode largest_mode, int volatilep)
{
enum machine_mode mode;
unsigned int unit = 0;
+ unsigned HOST_WIDE_INT maxbits;
+
+ /* If unset, no restriction. */
+ if (!bitregion_end)
+ maxbits = MAX_FIXED_MODE_SIZE;
+ else
+ maxbits = (bitregion_end - bitregion_start) % align + 1;
/* Find the narrowest integer mode that contains the bit field. */
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
&& bitpos / unit == (bitpos + bitsize - 1) / unit
&& unit <= BITS_PER_WORD
&& unit <= MIN (align, BIGGEST_ALIGNMENT)
+ && unit <= maxbits
&& (largest_mode == VOIDmode
|| unit <= GET_MODE_BITSIZE (largest_mode)))
wide_mode = tmode;
--- /dev/null
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 --param allow-store-data-races=0" } */
+
+/* Test that we don't store past VAR.K. */
+
+struct S
+{
+ volatile int i;
+ volatile int j: 32;
+ volatile int k: 15;
+ volatile char c[2];
+} var;
+
+void setit()
+{
+ var.k = 13;
+}
+
+/* { dg-final { scan-assembler-not "movl.*, var" } } */
--- /dev/null
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 --param allow-store-data-races=0" } */
+
+/* Make sure we don't narrow down to a QI or HI to store into VAR.J,
+ but instead use an SI. */
+
+struct S
+{
+ volatile int i: 4;
+ volatile int j: 4;
+ volatile int k: 8;
+ volatile int l: 8;
+ volatile int m: 8;
+} var;
+
+void setit()
+{
+ var.j = 5;
+}
+
+/* { dg-final { scan-assembler "movl.*, var" } } */
--- /dev/null
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 --param allow-store-data-races=0" } */
+
+struct bits
+{
+ char a;
+ int b:7;
+ int c:9;
+ unsigned char d;
+} x;
+
+/* Store into <c> should not clobber <d>. */
+void update_c(struct bits *p, int val)
+{
+ p -> c = val;
+}
+
+/* { dg-final { scan-assembler-not "movl" } } */
--- /dev/null
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 --param allow-store-data-races=0" } */
+
+#include <stdlib.h>
+
+struct bits
+{
+ char a;
+ int b:7;
+ int c:9;
+ unsigned char d;
+} x;
+
+struct bits *p;
+
+static void allocit()
+{
+ p = (struct bits *) malloc (sizeof (struct bits));
+}
+
+/* Store into <c> should not clobber <d>. */
+/* We should not use a 32-bit move to store into p->, but a smaller move. */
+void foo()
+{
+ allocit();
+ p -> c = 55;
+}
+
+/* { dg-final { scan-assembler-not "movl\t\\(" } } */
--- /dev/null
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 --param allow-store-data-races=0" } */
+
+/* Test that we don't store past VAR.A. */
+
+struct S
+{
+ volatile unsigned int a : 4;
+ unsigned char b;
+ unsigned int c : 6;
+} var;
+
+void set_a()
+{
+ var.a = 12;
+}
+
+/* { dg-final { scan-assembler-not "movl.*, var" } } */
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