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mips.c (mips_integer_op): New structure.

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* config/mips/mips.c (mips_integer_op): New structure.
	(MIPS_MAX_INTEGER_OPS): Define.
	(mips_const_insns): Use mips_build_integer to determine the number
	of instructions needed to load a CONST_INT.
	(move_operand): Reject compound CONST_INTs.
	(mips_build_shift, mips_build_lower, mips_build_integer): New fns.
	(mips_move_integer): New fn.
	(mips_legitimize_const_move): Pass CONST_INTs to mips_move_integer.
	(mips_legitimize_move): Only legitimize constants when moving
	word or subword values.

From-SVN: r66419
This commit is contained in:
Richard Sandiford 2003-05-03 08:10:17 +00:00 committed by Richard Sandiford
parent d4c67b6ee3
commit b259a9a6f7
2 changed files with 199 additions and 10 deletions
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13
gcc/ChangeLog
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@ -1,3 +1,16 @@
2003-05-03 Richard Sandiford <rsandifo@redhat.com>
* config/mips/mips.c (mips_integer_op): New structure.
(MIPS_MAX_INTEGER_OPS): Define.
(mips_const_insns): Use mips_build_integer to determine the number
of instructions needed to load a CONST_INT.
(move_operand): Reject compound CONST_INTs.
(mips_build_shift, mips_build_lower, mips_build_integer): New fns.
(mips_move_integer): New fn.
(mips_legitimize_const_move): Pass CONST_INTs to mips_move_integer.
(mips_legitimize_move): Only legitimize constants when moving
word or subword values.
2003-05-02 Matt Kraai <kraai@alumni.cmu.edu>
* Makefile.in (gcov-iov.h): Use move-if-change and a stamp.

196
gcc/config/mips/mips.c
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@ -179,6 +179,7 @@ struct constant;
struct mips_arg_info;
struct mips_constant_info;
struct mips_address_info;
struct mips_integer_op;
static enum mips_constant_type mips_classify_constant
PARAMS ((struct mips_constant_info *, rtx));
static enum mips_symbol_type mips_classify_symbol
@ -209,6 +210,13 @@ static rtx mips_emit_high PARAMS ((rtx, rtx));
static bool mips_legitimize_symbol PARAMS ((rtx, rtx *, int));
static rtx mips_reloc PARAMS ((rtx, int));
static rtx mips_lui_reloc PARAMS ((rtx, int));
static unsigned int mips_build_shift PARAMS ((struct mips_integer_op *,
HOST_WIDE_INT));
static unsigned int mips_build_lower PARAMS ((struct mips_integer_op *,
unsigned HOST_WIDE_INT));
static unsigned int mips_build_integer PARAMS ((struct mips_integer_op *,
unsigned HOST_WIDE_INT));
static void mips_move_integer PARAMS ((rtx, unsigned HOST_WIDE_INT));
static void mips_legitimize_const_move PARAMS ((enum machine_mode,
rtx, rtx));
static int m16_check_op PARAMS ((rtx, int, int, int));
@ -395,6 +403,29 @@ struct mips_address_info
};
/* One stage in a constant building sequence. These sequences have
the form:
A = VALUE[0]
A = A CODE[1] VALUE[1]
A = A CODE[2] VALUE[2]
...
where A is an accumulator, each CODE[i] is a binary rtl operation
and each VALUE[i] is a constant integer. */
struct mips_integer_op {
enum rtx_code code;
unsigned HOST_WIDE_INT value;
};
/* The largest number of operations needed to load an integer constant.
The worst accepted case for 64-bit constants is LUI,ORI,SLL,ORI,SLL,ORI.
When the lowest bit is clear, we can try, but reject a sequence with
an extra SLL at the end. */
#define MIPS_MAX_INTEGER_OPS 7
/* Global variables for machine-dependent things. */
/* Threshold for data being put into the small data/bss area, instead
@ -1255,6 +1286,7 @@ mips_const_insns (x)
rtx x;
{
struct mips_constant_info c;
struct mips_integer_op codes[MIPS_MAX_INTEGER_OPS];
switch (GET_CODE (x))
{
@ -1274,15 +1306,7 @@ mips_const_insns (x)
: SMALL_OPERAND_UNSIGNED (-INTVAL (x)) ? 3
: 0);
/* Return 1 for constants that can be loaded using ORI, ADDIU,
or LUI. Return 2 for constants that can be loaded using
LUI followed by ORI. Assume the worst case for all others.
(The worst case is: LUI, ORI, SLL, ORI, SLL, ORI.) */
return (SMALL_OPERAND (INTVAL (x)) ? 1
: SMALL_OPERAND_UNSIGNED (INTVAL (x)) ? 1
: LUI_OPERAND (INTVAL (x)) ? 1
: LUI_OPERAND (INTVAL (x) & ~(unsigned HOST_WIDE_INT) 0xffff) ? 2
: 6);
return mips_build_integer (codes, INTVAL (x));
case CONST_DOUBLE:
return (!TARGET_MIPS16 && x == CONST0_RTX (GET_MODE (x)) ? 1 : 0);
@ -1610,6 +1634,8 @@ move_operand (op, mode)
if (GET_CODE (op) == HIGH && TARGET_ABICALLS)
return false;
if (GET_CODE (op) == CONST_INT && !TARGET_MIPS16)
return (SMALL_INT (op) || SMALL_INT_UNSIGNED (op) || LUI_INT (op));
if (mips_classify_constant (&c, op) == CONSTANT_SYMBOLIC)
return mips_symbolic_address_p (c.symbol, c.offset, word_mode, 1);
return general_operand (op, mode);
@ -1938,6 +1964,144 @@ mips_legitimize_address (xloc, mode)
}
/* Subroutine of mips_build_integer (with the same interface).
Assume that the final action in the sequence should be a left shift. */
static unsigned int
mips_build_shift (codes, value)
struct mips_integer_op *codes;
HOST_WIDE_INT value;
{
unsigned int i, shift;
/* Shift VALUE right until its lowest bit is set. Shift arithmetically
since signed numbers are easier to load than unsigned ones. */
shift = 0;
while ((value & 1) == 0)
value /= 2, shift++;
i = mips_build_integer (codes, value);
codes[i].code = ASHIFT;
codes[i].value = shift;
return i + 1;
}
/* As for mips_build_shift, but assume that the final action will be
an IOR or PLUS operation. */
static unsigned int
mips_build_lower (codes, value)
struct mips_integer_op *codes;
unsigned HOST_WIDE_INT value;
{
unsigned HOST_WIDE_INT high;
unsigned int i;
high = value & ~(unsigned HOST_WIDE_INT) 0xffff;
if (!LUI_OPERAND (high) && (value & 0x18000) == 0x18000)
{
/* The constant is too complex to load with a simple lui/ori pair
so our goal is to clear as many trailing zeros as possible.
In this case, we know bit 16 is set and that the low 16 bits
form a negative number. If we subtract that number from VALUE,
we will clear at least the lowest 17 bits, maybe more. */
i = mips_build_integer (codes, CONST_HIGH_PART (value));
codes[i].code = PLUS;
codes[i].value = CONST_LOW_PART (value);
}
else
{
i = mips_build_integer (codes, high);
codes[i].code = IOR;
codes[i].value = value & 0xffff;
}
return i + 1;
}
/* Fill CODES with a sequence of rtl operations to load VALUE.
Return the number of operations needed. */
static unsigned int
mips_build_integer (codes, value)
struct mips_integer_op *codes;
unsigned HOST_WIDE_INT value;
{
if (SMALL_OPERAND (value)
|| SMALL_OPERAND_UNSIGNED (value)
|| LUI_OPERAND (value))
{
/* The value can be loaded with a single instruction. */
codes[0].code = NIL;
codes[0].value = value;
return 1;
}
else if ((value & 1) != 0 || LUI_OPERAND (CONST_HIGH_PART (value)))
{
/* Either the constant is a simple LUI/ORI combination or its
lowest bit is set. We don't want to shift in this case. */
return mips_build_lower (codes, value);
}
else if ((value & 0xffff) == 0)
{
/* The constant will need at least three actions. The lowest
16 bits are clear, so the final action will be a shift. */
return mips_build_shift (codes, value);
}
else
{
/* The final action could be a shift, add or inclusive OR.
Rather than use a complex condition to select the best
approach, try both mips_build_shift and mips_build_lower
and pick the one that gives the shortest sequence.
Note that this case is only used once per constant. */
struct mips_integer_op alt_codes[MIPS_MAX_INTEGER_OPS];
unsigned int cost, alt_cost;
cost = mips_build_shift (codes, value);
alt_cost = mips_build_lower (alt_codes, value);
if (alt_cost < cost)
{
memcpy (codes, alt_codes, alt_cost * sizeof (codes[0]));
cost = alt_cost;
}
return cost;
}
}
/* Move VALUE into register DEST. */
static void
mips_move_integer (dest, value)
rtx dest;
unsigned HOST_WIDE_INT value;
{
struct mips_integer_op codes[MIPS_MAX_INTEGER_OPS];
enum machine_mode mode;
unsigned int i, cost;
rtx x;
mode = GET_MODE (dest);
cost = mips_build_integer (codes, value);
/* Apply each binary operation to X. Invariant: X is a legitimate
source operand for a SET pattern. */
x = GEN_INT (codes[0].value);
for (i = 1; i < cost; i++)
{
if (no_new_pseudos)
emit_move_insn (dest, x), x = dest;
else
x = force_reg (mode, x);
x = gen_rtx_fmt_ee (codes[i].code, mode, x, GEN_INT (codes[i].value));
}
emit_insn (gen_rtx_SET (VOIDmode, dest, x));
}
/* Subroutine of mips_legitimize_move. Move constant SRC into register
DEST given that SRC satisfies immediate_operand but doesn't satisfy
move_operand. */
@ -1958,6 +2122,12 @@ mips_legitimize_const_move (mode, dest, src)
return;
}
if (GET_CODE (src) == CONST_INT && !TARGET_MIPS16)
{
mips_move_integer (dest, INTVAL (src));
return;
}
/* Fetch global symbols from the GOT. */
if (TARGET_EXPLICIT_RELOCS
&& GET_CODE (src) == SYMBOL_REF
@ -2007,7 +2177,13 @@ mips_legitimize_move (mode, dest, src)
return true;
}
if (CONSTANT_P (src) && !move_operand (src, mode))
/* The source of an SImode move must be a move_operand. Likewise
DImode moves on 64-bit targets. We need to deal with constants
that would be legitimate immediate_operands but not legitimate
move_operands. */
if (GET_MODE_SIZE (mode) <= UNITS_PER_WORD
&& CONSTANT_P (src)
&& !move_operand (src, mode))
{
mips_legitimize_const_move (mode, dest, src);
set_unique_reg_note (get_last_insn (), REG_EQUAL, copy_rtx (src));