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rtl.h (subreg_lsb): Declare.

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* rtl.h (subreg_lsb): Declare.
	* rtlanal.c (subreg_lsb): Implement.

From-SVN: r48272
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John Wehle 2001-12-22 17:23:52 +00:00 committed by John Wehle
parent d599b3fc8a
commit 33aceff285
3 changed files with 49 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Sat Dec 22 12:20:20 EST 2001 John Wehle (john@feith.com)
* rtl.h (subreg_lsb): Declare.
* rtlanal.c (subreg_lsb): Implement.
Sat Dec 22 08:59:50 2001 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* predict.c: Reformatting and minor cleanups.

1
gcc/rtl.h
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@ -818,6 +818,7 @@ extern const char * const note_insn_name[NOTE_INSN_MAX - NOTE_INSN_BIAS];
#define SUBREG_BYTE(RTX) XCUINT(RTX, 1, SUBREG)
/* in rtlanal.c */
extern unsigned int subreg_lsb PARAMS ((rtx));
extern unsigned int subreg_regno_offset PARAMS ((unsigned int,
enum machine_mode,
unsigned int,

43
gcc/rtlanal.c
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@ -2881,6 +2881,49 @@ loc_mentioned_in_p (loc, in)
return 0;
}
/* Given a subreg X, return the bit offset where the subreg begins
(counting from the least significant bit of the reg). */
unsigned int
subreg_lsb (x)
rtx x;
{
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (x));
enum machine_mode mode = GET_MODE (x);
unsigned int bitpos;
unsigned int byte;
unsigned int word;
/* A paradoxical subreg begins at bit position 0. */
if (GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (inner_mode))
return 0;
if (WORDS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
/* If the subreg crosses a word boundary ensure that
it also begins and ends on a word boundary. */
if ((SUBREG_BYTE (x) % UNITS_PER_WORD
+ GET_MODE_SIZE (mode)) > UNITS_PER_WORD
&& (SUBREG_BYTE (x) % UNITS_PER_WORD
|| GET_MODE_SIZE (mode) % UNITS_PER_WORD))
abort ();
if (WORDS_BIG_ENDIAN)
word = (GET_MODE_SIZE (inner_mode)
- (SUBREG_BYTE (x) + GET_MODE_SIZE (mode))) / UNITS_PER_WORD;
else
word = SUBREG_BYTE (x) / UNITS_PER_WORD;
bitpos = word * BITS_PER_WORD;
if (BYTES_BIG_ENDIAN)
byte = (GET_MODE_SIZE (inner_mode)
- (SUBREG_BYTE (x) + GET_MODE_SIZE (mode))) % UNITS_PER_WORD;
else
byte = SUBREG_BYTE (x) % UNITS_PER_WORD;
bitpos += byte * BITS_PER_UNIT;
return bitpos;
}
/* This function returns the regno offset of a subreg expression.
xregno - A regno of an inner hard subreg_reg (or what will become one).
xmode - The mode of xregno.