Add more subreg offset helpers

Provide versions of subreg_lowpart_offset and subreg_highpart_offset
that work on mode sizes rather than modes.  Also provide a routine
that converts an lsb position to a subreg offset.

The intent (in combination with later patches) is to move the
handling of the BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN case into
just two places, so that for other combinations we don't have
to split offsets into words and subwords.

gcc/
2016-11-15  Richard Sandiford  <richard.sandiford@arm.com>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

	* rtl.h (subreg_size_offset_from_lsb): Declare.
	(subreg_offset_from_lsb): New function.
	(subreg_size_lowpart_offset): Declare.
	(subreg_lowpart_offset): Turn into an inline function.
	(subreg_size_highpart_offset): Declare.
	(subreg_highpart_offset): Turn into an inline function.
	* emit-rtl.c (subreg_size_lowpart_offset): New function.
	(subreg_size_highpart_offset): Likewise
	* rtlanal.c (subreg_size_offset_from_lsb): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r242755
This commit is contained in:
Richard Sandiford 2016-11-23 14:31:13 +00:00 committed by Richard Sandiford
parent cbb88345e1
commit 33951763a8
4 changed files with 116 additions and 33 deletions

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@ -1,3 +1,17 @@
2016-11-23 Richard Sandiford <richard.sandiford@arm.com>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
* rtl.h (subreg_size_offset_from_lsb): Declare.
(subreg_offset_from_lsb): New function.
(subreg_size_lowpart_offset): Declare.
(subreg_lowpart_offset): Turn into an inline function.
(subreg_size_highpart_offset): Declare.
(subreg_highpart_offset): Turn into an inline function.
* emit-rtl.c (subreg_size_lowpart_offset): New function.
(subreg_size_highpart_offset): Likewise
* rtlanal.c (subreg_size_offset_from_lsb): Likewise.
2016-11-23 Richard Biener <rguenther@suse.de>
PR tree-optimization/78482

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@ -1478,44 +1478,41 @@ gen_highpart_mode (machine_mode outermode, machine_mode innermode, rtx exp)
subreg_highpart_offset (outermode, innermode));
}
/* Return the SUBREG_BYTE for an OUTERMODE lowpart of an INNERMODE value. */
/* Return the SUBREG_BYTE for a lowpart subreg whose outer mode has
OUTER_BYTES bytes and whose inner mode has INNER_BYTES bytes. */
unsigned int
subreg_lowpart_offset (machine_mode outermode, machine_mode innermode)
subreg_size_lowpart_offset (unsigned int outer_bytes, unsigned int inner_bytes)
{
unsigned int offset = 0;
int difference = (GET_MODE_SIZE (innermode) - GET_MODE_SIZE (outermode));
if (outer_bytes > inner_bytes)
/* Paradoxical subregs always have a SUBREG_BYTE of 0. */
return 0;
if (difference > 0)
{
if (WORDS_BIG_ENDIAN)
offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
if (BYTES_BIG_ENDIAN)
offset += difference % UNITS_PER_WORD;
}
return offset;
if (BYTES_BIG_ENDIAN && WORDS_BIG_ENDIAN)
return inner_bytes - outer_bytes;
else if (!BYTES_BIG_ENDIAN && !WORDS_BIG_ENDIAN)
return 0;
else
return subreg_size_offset_from_lsb (outer_bytes, inner_bytes, 0);
}
/* Return offset in bytes to get OUTERMODE high part
of the value in mode INNERMODE stored in memory in target format. */
/* Return the SUBREG_BYTE for a highpart subreg whose outer mode has
OUTER_BYTES bytes and whose inner mode has INNER_BYTES bytes. */
unsigned int
subreg_highpart_offset (machine_mode outermode, machine_mode innermode)
subreg_size_highpart_offset (unsigned int outer_bytes,
unsigned int inner_bytes)
{
unsigned int offset = 0;
int difference = (GET_MODE_SIZE (innermode) - GET_MODE_SIZE (outermode));
gcc_assert (inner_bytes >= outer_bytes);
gcc_assert (GET_MODE_SIZE (innermode) >= GET_MODE_SIZE (outermode));
if (difference > 0)
{
if (! WORDS_BIG_ENDIAN)
offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
if (! BYTES_BIG_ENDIAN)
offset += difference % UNITS_PER_WORD;
}
return offset;
if (BYTES_BIG_ENDIAN && WORDS_BIG_ENDIAN)
return 0;
else if (!BYTES_BIG_ENDIAN && !WORDS_BIG_ENDIAN)
return inner_bytes - outer_bytes;
else
return subreg_size_offset_from_lsb (outer_bytes, inner_bytes,
(inner_bytes - outer_bytes)
* BITS_PER_UNIT);
}
/* Return 1 iff X, assumed to be a SUBREG,

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@ -2178,6 +2178,24 @@ extern void get_full_rtx_cost (rtx, machine_mode, enum rtx_code, int,
extern unsigned int subreg_lsb (const_rtx);
extern unsigned int subreg_lsb_1 (machine_mode, machine_mode,
unsigned int);
extern unsigned int subreg_size_offset_from_lsb (unsigned int, unsigned int,
unsigned int);
/* Return the subreg byte offset for a subreg whose outer mode is
OUTER_MODE, whose inner mode is INNER_MODE, and where there are
LSB_SHIFT *bits* between the lsb of the outer value and the lsb of
the inner value. This is the inverse of subreg_lsb_1 (which converts
byte offsets to bit shifts). */
inline unsigned int
subreg_offset_from_lsb (machine_mode outer_mode,
machine_mode inner_mode,
unsigned int lsb_shift)
{
return subreg_size_offset_from_lsb (GET_MODE_SIZE (outer_mode),
GET_MODE_SIZE (inner_mode), lsb_shift);
}
extern unsigned int subreg_regno_offset (unsigned int, machine_mode,
unsigned int, machine_mode);
extern bool subreg_offset_representable_p (unsigned int, machine_mode,
@ -2764,10 +2782,28 @@ extern rtx operand_subword (rtx, unsigned int, int, machine_mode);
extern rtx operand_subword_force (rtx, unsigned int, machine_mode);
extern bool paradoxical_subreg_p (const_rtx);
extern int subreg_lowpart_p (const_rtx);
extern unsigned int subreg_lowpart_offset (machine_mode,
machine_mode);
extern unsigned int subreg_highpart_offset (machine_mode,
machine_mode);
extern unsigned int subreg_size_lowpart_offset (unsigned int, unsigned int);
/* Return the SUBREG_BYTE for an OUTERMODE lowpart of an INNERMODE value. */
inline unsigned int
subreg_lowpart_offset (machine_mode outermode, machine_mode innermode)
{
return subreg_size_lowpart_offset (GET_MODE_SIZE (outermode),
GET_MODE_SIZE (innermode));
}
extern unsigned int subreg_size_highpart_offset (unsigned int, unsigned int);
/* Return the SUBREG_BYTE for an OUTERMODE highpart of an INNERMODE value. */
inline unsigned int
subreg_highpart_offset (machine_mode outermode, machine_mode innermode)
{
return subreg_size_highpart_offset (GET_MODE_SIZE (outermode),
GET_MODE_SIZE (innermode));
}
extern int byte_lowpart_offset (machine_mode, machine_mode);
extern rtx make_safe_from (rtx, rtx);
extern rtx convert_memory_address_addr_space_1 (machine_mode, rtx,

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@ -3528,6 +3528,42 @@ subreg_lsb (const_rtx x)
SUBREG_BYTE (x));
}
/* Return the subreg byte offset for a subreg whose outer value has
OUTER_BYTES bytes, whose inner value has INNER_BYTES bytes, and where
there are LSB_SHIFT *bits* between the lsb of the outer value and the
lsb of the inner value. This is the inverse of the calculation
performed by subreg_lsb_1 (which converts byte offsets to bit shifts). */
unsigned int
subreg_size_offset_from_lsb (unsigned int outer_bytes,
unsigned int inner_bytes,
unsigned int lsb_shift)
{
/* A paradoxical subreg begins at bit position 0. */
if (outer_bytes > inner_bytes)
{
gcc_checking_assert (lsb_shift == 0);
return 0;
}
gcc_assert (lsb_shift % BITS_PER_UNIT == 0);
unsigned int lower_bytes = lsb_shift / BITS_PER_UNIT;
unsigned int upper_bytes = inner_bytes - (lower_bytes + outer_bytes);
if (WORDS_BIG_ENDIAN && BYTES_BIG_ENDIAN)
return upper_bytes;
else if (!WORDS_BIG_ENDIAN && !BYTES_BIG_ENDIAN)
return lower_bytes;
else
{
unsigned int lower_word_part = lower_bytes & -UNITS_PER_WORD;
unsigned int upper_word_part = upper_bytes & -UNITS_PER_WORD;
if (WORDS_BIG_ENDIAN)
return upper_word_part + (lower_bytes - lower_word_part);
else
return lower_word_part + (upper_bytes - upper_word_part);
}
}
/* Fill in information about a subreg of a hard register.
xregno - A regno of an inner hard subreg_reg (or what will become one).
xmode - The mode of xregno.