/* Analyze RTL for C-Compiler
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
#include "config.h"
#include "output.h"
#include "tm_p.h"
#include "flags.h"
-#include "basic-block.h"
#include "real.h"
#include "regs.h"
#include "function.h"
/* Forward declarations */
static int global_reg_mentioned_p_1 (rtx *, void *);
static void set_of_1 (rtx, rtx, void *);
+static bool covers_regno_p (rtx, unsigned int);
+static bool covers_regno_no_parallel_p (rtx, unsigned int);
static int rtx_referenced_p_1 (rtx *, void *);
static int computed_jump_p_1 (rtx);
static void parms_set (rtx, rtx, void *);
static unsigned int num_sign_bit_copies1 (rtx, enum machine_mode, rtx,
enum machine_mode, unsigned int);
+/* Offset of the first 'e', 'E' or 'V' operand for each rtx code, or
+ -1 if a code has no such operand. */
+static int non_rtx_starting_operands[NUM_RTX_CODE];
+
/* Bit flags that specify the machine subtype we are compiling for.
Bits are tested using macros TARGET_... defined in the tm.h file
and set by `-m...' switches. Must be defined in rtlanal.c. */
for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
if (INSN_P (insn)
&& (reg_overlap_mentioned_p (reg, PATTERN (insn))
- || (CALL_P (insn)
- && (find_reg_fusage (insn, USE, reg)
- || find_reg_fusage (insn, CLOBBER, reg)))))
+ || (CALL_P (insn) && find_reg_fusage (insn, USE, reg))))
return 1;
return 0;
}
}
/* Similar to reg_set_between_p, but check all registers in X. Return 0
- only if none of them are modified between START and END. Do not
- consider non-registers one way or the other. */
-
-int
-regs_set_between_p (rtx x, rtx start, rtx end)
-{
- enum rtx_code code = GET_CODE (x);
- const char *fmt;
- int i, j;
-
- switch (code)
- {
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_VECTOR:
- case CONST:
- case SYMBOL_REF:
- case LABEL_REF:
- case PC:
- case CC0:
- return 0;
-
- case REG:
- return reg_set_between_p (x, start, end);
-
- default:
- break;
- }
-
- fmt = GET_RTX_FORMAT (code);
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e' && regs_set_between_p (XEXP (x, i), start, end))
- return 1;
-
- else if (fmt[i] == 'E')
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- if (regs_set_between_p (XVECEXP (x, i, j), start, end))
- return 1;
- }
-
- return 0;
-}
-
-/* Similar to reg_set_between_p, but check all registers in X. Return 0
only if none of them are modified between START and END. Return 1 if
X contains a MEM; this routine does usememory aliasing. */
return 1;
case MEM:
- if (MEM_READONLY_P (x))
- return 0;
if (modified_between_p (XEXP (x, 0), start, end))
return 1;
+ if (MEM_READONLY_P (x))
+ return 0;
for (insn = NEXT_INSN (start); insn != end; insn = NEXT_INSN (insn))
if (memory_modified_in_insn_p (x, insn))
return 1;
return 1;
case MEM:
- if (MEM_READONLY_P (x))
- return 0;
if (modified_in_p (XEXP (x, 0), insn))
return 1;
+ if (MEM_READONLY_P (x))
+ return 0;
if (memory_modified_in_insn_p (x, insn))
return 1;
return 0;
if (MEM_P (dst) && MEM_P (src))
return rtx_equal_p (dst, src) && !side_effects_p (dst);
- if (GET_CODE (dst) == SIGN_EXTRACT
- || GET_CODE (dst) == ZERO_EXTRACT)
+ if (GET_CODE (dst) == ZERO_EXTRACT)
return rtx_equal_p (XEXP (dst, 0), src)
&& ! BYTES_BIG_ENDIAN && XEXP (dst, 2) == const0_rtx
&& !side_effects_p (src);
fmt = GET_RTX_FORMAT (GET_CODE (in));
for (i = GET_RTX_LENGTH (GET_CODE (in)) - 1; i >= 0; i--)
- if (fmt[i] == 'e' && reg_overlap_mentioned_p (x, XEXP (in, i)))
- return 1;
+ if (fmt[i] == 'e')
+ {
+ if (reg_overlap_mentioned_p (x, XEXP (in, i)))
+ return 1;
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
+ for (j = XVECLEN (in, i) - 1; j >= 0; --j)
+ if (reg_overlap_mentioned_p (x, XVECEXP (in, i, j)))
+ return 1;
+ }
return 0;
}
&& (!REG_P (SUBREG_REG (dest))
|| REGNO (SUBREG_REG (dest)) >= FIRST_PSEUDO_REGISTER))
|| GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == SIGN_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
This will be true if X is (cc0) or if X is a register and
X dies in INSN or because INSN entirely sets X.
- "Entirely set" means set directly and not through a SUBREG,
- ZERO_EXTRACT or SIGN_EXTRACT, so no trace of the old contents remains.
+ "Entirely set" means set directly and not through a SUBREG, or
+ ZERO_EXTRACT, so no trace of the old contents remains.
Likewise, REG_INC does not count.
REG may be a hard or pseudo reg. Renumbering is not taken into account,
return 1;
}
+/* Return TRUE iff DEST is a register or subreg of a register and
+ doesn't change the number of words of the inner register, and any
+ part of the register is TEST_REGNO. */
+
+static bool
+covers_regno_no_parallel_p (rtx dest, unsigned int test_regno)
+{
+ unsigned int regno, endregno;
+
+ if (GET_CODE (dest) == SUBREG
+ && (((GET_MODE_SIZE (GET_MODE (dest))
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
+ == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
+ dest = SUBREG_REG (dest);
+
+ if (!REG_P (dest))
+ return false;
+
+ regno = REGNO (dest);
+ endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
+ : regno + hard_regno_nregs[regno][GET_MODE (dest)]);
+ return (test_regno >= regno && test_regno < endregno);
+}
+
+/* Like covers_regno_no_parallel_p, but also handles PARALLELs where
+ any member matches the covers_regno_no_parallel_p criteria. */
+
+static bool
+covers_regno_p (rtx dest, unsigned int test_regno)
+{
+ if (GET_CODE (dest) == PARALLEL)
+ {
+ /* Some targets place small structures in registers for return
+ values of functions, and those registers are wrapped in
+ PARALLELs that we may see as the destination of a SET. */
+ int i;
+
+ for (i = XVECLEN (dest, 0) - 1; i >= 0; i--)
+ {
+ rtx inner = XEXP (XVECEXP (dest, 0, i), 0);
+ if (inner != NULL_RTX
+ && covers_regno_no_parallel_p (inner, test_regno))
+ return true;
+ }
+
+ return false;
+ }
+ else
+ return covers_regno_no_parallel_p (dest, test_regno);
+}
+
/* Utility function for dead_or_set_p to check an individual register. Also
called from flow.c. */
int
dead_or_set_regno_p (rtx insn, unsigned int test_regno)
{
- unsigned int regno, endregno;
rtx pattern;
/* See if there is a death note for something that includes TEST_REGNO. */
pattern = COND_EXEC_CODE (pattern);
if (GET_CODE (pattern) == SET)
- {
- rtx dest = SET_DEST (pattern);
-
- /* A value is totally replaced if it is the destination or the
- destination is a SUBREG of REGNO that does not change the number of
- words in it. */
- if (GET_CODE (dest) == SUBREG
- && (((GET_MODE_SIZE (GET_MODE (dest))
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
- == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
- dest = SUBREG_REG (dest);
-
- if (!REG_P (dest))
- return 0;
-
- regno = REGNO (dest);
- endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
- : regno + hard_regno_nregs[regno][GET_MODE (dest)]);
-
- return (test_regno >= regno && test_regno < endregno);
- }
+ return covers_regno_p (SET_DEST (pattern), test_regno);
else if (GET_CODE (pattern) == PARALLEL)
{
int i;
if (GET_CODE (body) == COND_EXEC)
body = COND_EXEC_CODE (body);
- if (GET_CODE (body) == SET || GET_CODE (body) == CLOBBER)
- {
- rtx dest = SET_DEST (body);
-
- if (GET_CODE (dest) == SUBREG
- && (((GET_MODE_SIZE (GET_MODE (dest))
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
- == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
- dest = SUBREG_REG (dest);
-
- if (!REG_P (dest))
- continue;
-
- regno = REGNO (dest);
- endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
- : regno + hard_regno_nregs[regno][GET_MODE (dest)]);
-
- if (test_regno >= regno && test_regno < endregno)
- return 1;
- }
+ if ((GET_CODE (body) == SET || GET_CODE (body) == CLOBBER)
+ && covers_regno_p (SET_DEST (body), test_regno))
+ return 1;
}
}
case UMOD:
if (HONOR_SNANS (GET_MODE (x)))
return 1;
- if (! CONSTANT_P (XEXP (x, 1))
- || (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT
- && flag_trapping_math))
- return 1;
- if (XEXP (x, 1) == const0_rtx)
+ if (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT)
+ return flag_trapping_math;
+ if (!CONSTANT_P (XEXP (x, 1)) || (XEXP (x, 1) == const0_rtx))
return 1;
break;
case NEG:
case ABS:
+ case SUBREG:
/* These operations don't trap even with floating point. */
break;
return 0;
}
+/* Optimized loop of for_each_rtx, trying to avoid useless recursive
+ calls. Processes the subexpressions of EXP and passes them to F. */
+static int
+for_each_rtx_1 (rtx exp, int n, rtx_function f, void *data)
+{
+ int result, i, j;
+ const char *format = GET_RTX_FORMAT (GET_CODE (exp));
+ rtx *x;
+
+ for (; format[n] != '\0'; n++)
+ {
+ switch (format[n])
+ {
+ case 'e':
+ /* Call F on X. */
+ x = &XEXP (exp, n);
+ result = (*f) (x, data);
+ if (result == -1)
+ /* Do not traverse sub-expressions. */
+ continue;
+ else if (result != 0)
+ /* Stop the traversal. */
+ return result;
+
+ if (*x == NULL_RTX)
+ /* There are no sub-expressions. */
+ continue;
+
+ i = non_rtx_starting_operands[GET_CODE (*x)];
+ if (i >= 0)
+ {
+ result = for_each_rtx_1 (*x, i, f, data);
+ if (result != 0)
+ return result;
+ }
+ break;
+
+ case 'V':
+ case 'E':
+ if (XVEC (exp, n) == 0)
+ continue;
+ for (j = 0; j < XVECLEN (exp, n); ++j)
+ {
+ /* Call F on X. */
+ x = &XVECEXP (exp, n, j);
+ result = (*f) (x, data);
+ if (result == -1)
+ /* Do not traverse sub-expressions. */
+ continue;
+ else if (result != 0)
+ /* Stop the traversal. */
+ return result;
+
+ if (*x == NULL_RTX)
+ /* There are no sub-expressions. */
+ continue;
+
+ i = non_rtx_starting_operands[GET_CODE (*x)];
+ if (i >= 0)
+ {
+ result = for_each_rtx_1 (*x, i, f, data);
+ if (result != 0)
+ return result;
+ }
+ }
+ break;
+
+ default:
+ /* Nothing to do. */
+ break;
+ }
+ }
+
+ return 0;
+}
+
/* Traverse X via depth-first search, calling F for each
sub-expression (including X itself). F is also passed the DATA.
If F returns -1, do not traverse sub-expressions, but continue
for_each_rtx (rtx *x, rtx_function f, void *data)
{
int result;
- int length;
- const char *format;
int i;
/* Call F on X. */
/* There are no sub-expressions. */
return 0;
- length = GET_RTX_LENGTH (GET_CODE (*x));
- format = GET_RTX_FORMAT (GET_CODE (*x));
-
- for (i = 0; i < length; ++i)
- {
- switch (format[i])
- {
- case 'e':
- result = for_each_rtx (&XEXP (*x, i), f, data);
- if (result != 0)
- return result;
- break;
-
- case 'V':
- case 'E':
- if (XVEC (*x, i) != 0)
- {
- int j;
- for (j = 0; j < XVECLEN (*x, i); ++j)
- {
- result = for_each_rtx (&XVECEXP (*x, i, j), f, data);
- if (result != 0)
- return result;
- }
- }
- break;
-
- default:
- /* Nothing to do. */
- break;
- }
-
- }
+ i = non_rtx_starting_operands[GET_CODE (*x)];
+ if (i < 0)
+ return 0;
- return 0;
+ return for_each_rtx_1 (*x, i, f, data);
}
+
/* Searches X for any reference to REGNO, returning the rtx of the
reference found if any. Otherwise, returns NULL_RTX. */
subreg_regno_offset (unsigned int xregno, enum machine_mode xmode,
unsigned int offset, enum machine_mode ymode)
{
- int nregs_xmode, nregs_ymode;
+ int nregs_xmode, nregs_ymode, nregs_xmode_unit_int;
int mode_multiple, nregs_multiple;
int y_offset;
+ enum machine_mode xmode_unit, xmode_unit_int;
gcc_assert (xregno < FIRST_PSEUDO_REGISTER);
- nregs_xmode = hard_regno_nregs[xregno][xmode];
+ if (GET_MODE_INNER (xmode) == VOIDmode)
+ xmode_unit = xmode;
+ else
+ xmode_unit = GET_MODE_INNER (xmode);
+
+ if (FLOAT_MODE_P (xmode_unit))
+ {
+ xmode_unit_int = int_mode_for_mode (xmode_unit);
+ if (xmode_unit_int == BLKmode)
+ /* It's probably bad to be here; a port should have an integer mode
+ that's the same size as anything of which it takes a SUBREG. */
+ xmode_unit_int = xmode_unit;
+ }
+ else
+ xmode_unit_int = xmode_unit;
+
+ nregs_xmode_unit_int = hard_regno_nregs[xregno][xmode_unit_int];
+
+ /* Adjust nregs_xmode to allow for 'holes'. */
+ if (nregs_xmode_unit_int != hard_regno_nregs[xregno][xmode_unit])
+ nregs_xmode = nregs_xmode_unit_int * GET_MODE_NUNITS (xmode);
+ else
+ nregs_xmode = hard_regno_nregs[xregno][xmode];
+
nregs_ymode = hard_regno_nregs[xregno][ymode];
/* If this is a big endian paradoxical subreg, which uses more actual
if (offset == 0 || nregs_xmode == nregs_ymode)
return 0;
- /* size of ymode must not be greater than the size of xmode. */
+ /* Size of ymode must not be greater than the size of xmode. */
mode_multiple = GET_MODE_SIZE (xmode) / GET_MODE_SIZE (ymode);
gcc_assert (mode_multiple != 0);
xmode - The mode of xregno.
offset - The byte offset.
ymode - The mode of a top level SUBREG (or what may become one).
- RETURN - The regno offset which would be used. */
+ RETURN - Whether the offset is representable. */
bool
subreg_offset_representable_p (unsigned int xregno, enum machine_mode xmode,
unsigned int offset, enum machine_mode ymode)
{
- int nregs_xmode, nregs_ymode;
+ int nregs_xmode, nregs_ymode, nregs_xmode_unit, nregs_xmode_unit_int;
int mode_multiple, nregs_multiple;
int y_offset;
+ enum machine_mode xmode_unit, xmode_unit_int;
gcc_assert (xregno < FIRST_PSEUDO_REGISTER);
- nregs_xmode = hard_regno_nregs[xregno][xmode];
+ if (GET_MODE_INNER (xmode) == VOIDmode)
+ xmode_unit = xmode;
+ else
+ xmode_unit = GET_MODE_INNER (xmode);
+
+ if (FLOAT_MODE_P (xmode_unit))
+ {
+ xmode_unit_int = int_mode_for_mode (xmode_unit);
+ if (xmode_unit_int == BLKmode)
+ /* It's probably bad to be here; a port should have an integer mode
+ that's the same size as anything of which it takes a SUBREG. */
+ xmode_unit_int = xmode_unit;
+ }
+ else
+ xmode_unit_int = xmode_unit;
+
+ nregs_xmode_unit = hard_regno_nregs[xregno][xmode_unit];
+ nregs_xmode_unit_int = hard_regno_nregs[xregno][xmode_unit_int];
+
+ /* If there are holes in a non-scalar mode in registers, we expect
+ that it is made up of its units concatenated together. */
+ if (nregs_xmode_unit != nregs_xmode_unit_int)
+ {
+ gcc_assert (nregs_xmode_unit * GET_MODE_NUNITS (xmode)
+ == hard_regno_nregs[xregno][xmode]);
+
+ /* You can only ask for a SUBREG of a value with holes in the middle
+ if you don't cross the holes. (Such a SUBREG should be done by
+ picking a different register class, or doing it in memory if
+ necessary.) An example of a value with holes is XCmode on 32-bit
+ x86 with -m128bit-long-double; it's represented in 6 32-bit registers,
+ 3 for each part, but in memory it's two 128-bit parts.
+ Padding is assumed to be at the end (not necessarily the 'high part')
+ of each unit. */
+ if (nregs_xmode_unit != nregs_xmode_unit_int
+ && (offset / GET_MODE_SIZE (xmode_unit_int) + 1
+ < GET_MODE_NUNITS (xmode))
+ && (offset / GET_MODE_SIZE (xmode_unit_int)
+ != ((offset + GET_MODE_SIZE (ymode) - 1)
+ / GET_MODE_SIZE (xmode_unit_int))))
+ return false;
+
+ nregs_xmode = nregs_xmode_unit_int * GET_MODE_NUNITS (xmode);
+ }
+ else
+ nregs_xmode = hard_regno_nregs[xregno][xmode];
+
nregs_ymode = hard_regno_nregs[xregno][ymode];
- /* Paradoxical subregs are always valid. */
+ /* Paradoxical subregs are otherwise valid. */
if (offset == 0
&& nregs_ymode > nregs_xmode
&& (GET_MODE_SIZE (ymode) > UNITS_PER_WORD
? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
return true;
- /* Lowpart subregs are always valid. */
+ /* Lowpart subregs are otherwise valid. */
if (offset == subreg_lowpart_offset (ymode, xmode))
return true;
- /* This should always pass, otherwise we don't know how to verify the
- constraint. These conditions may be relaxed but subreg_offset would
- need to be redesigned. */
+ /* This should always pass, otherwise we don't know how to verify
+ the constraint. These conditions may be relaxed but
+ subreg_regno_offset would need to be redesigned. */
gcc_assert ((GET_MODE_SIZE (xmode) % GET_MODE_SIZE (ymode)) == 0);
- gcc_assert ((GET_MODE_SIZE (ymode) % nregs_ymode) == 0);
gcc_assert ((nregs_xmode % nregs_ymode) == 0);
/* The XMODE value can be seen as a vector of NREGS_XMODE
/ nregs_xmode,
MODE_INT, 0));
- /* size of ymode must not be greater than the size of xmode. */
+ /* Size of ymode must not be greater than the size of xmode. */
mode_multiple = GET_MODE_SIZE (xmode) / GET_MODE_SIZE (ymode);
gcc_assert (mode_multiple != 0);
}
/* Look backward for first parameter to be loaded.
+ Note that loads of all parameters will not necessarily be
+ found if CSE has eliminated some of them (e.g., an argument
+ to the outer function is passed down as a parameter).
Do not skip BOUNDARY. */
rtx
find_first_parameter_load (rtx call_insn, rtx boundary)
{
struct parms_set_data parm;
- rtx p, before;
+ rtx p, before, first_set;
/* Since different machines initialize their parameter registers
in different orders, assume nothing. Collect the set of all
parm.nregs++;
}
before = call_insn;
+ first_set = call_insn;
/* Search backward for the first set of a register in this set. */
while (parm.nregs && before != boundary)
}
if (INSN_P (before))
- note_stores (PATTERN (before), parms_set, &parm);
+ {
+ int nregs_old = parm.nregs;
+ note_stores (PATTERN (before), parms_set, &parm);
+ /* If we found something that did not set a parameter reg,
+ we're done. Do not keep going, as that might result
+ in hoisting an insn before the setting of a pseudo
+ that is used by the hoisted insn. */
+ if (nregs_old != parm.nregs)
+ first_set = before;
+ else
+ break;
+ }
}
- return before;
+ return first_set;
}
/* Return true if we should avoid inserting code between INSN and preceding
return 0;
case SUBREG:
+ total = 0;
/* If we can't tie these modes, make this expensive. The larger
the mode, the more expensive it is. */
if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x))))
case GE: case GEU: case UNGE:
case LE: case LEU: case UNLE:
case UNORDERED: case ORDERED:
-
/* If this produces an integer result, we know which bits are set.
Code here used to clear bits outside the mode of X, but that is
now done above. */
-
- if (GET_MODE_CLASS (mode) == MODE_INT
+ /* Mind that MODE is the mode the caller wants to look at this
+ operation in, and not the actual operation mode. We can wind
+ up with (subreg:DI (gt:V4HI x y)), and we don't have anything
+ that describes the results of a vector compare. */
+ if (GET_MODE_CLASS (GET_MODE (x)) == MODE_INT
&& mode_width <= HOST_BITS_PER_WIDE_INT)
nonzero = STORE_FLAG_VALUE;
break;
cost = rtx_cost (SET_SRC (set), SET);
return cost > 0 ? cost : COSTS_N_INSNS (1);
}
+
+/* Given an insn INSN and condition COND, return the condition in a
+ canonical form to simplify testing by callers. Specifically:
+
+ (1) The code will always be a comparison operation (EQ, NE, GT, etc.).
+ (2) Both operands will be machine operands; (cc0) will have been replaced.
+ (3) If an operand is a constant, it will be the second operand.
+ (4) (LE x const) will be replaced with (LT x <const+1>) and similarly
+ for GE, GEU, and LEU.
+
+ If the condition cannot be understood, or is an inequality floating-point
+ comparison which needs to be reversed, 0 will be returned.
+
+ If REVERSE is nonzero, then reverse the condition prior to canonizing it.
+
+ If EARLIEST is nonzero, it is a pointer to a place where the earliest
+ insn used in locating the condition was found. If a replacement test
+ of the condition is desired, it should be placed in front of that
+ insn and we will be sure that the inputs are still valid.
+
+ If WANT_REG is nonzero, we wish the condition to be relative to that
+ register, if possible. Therefore, do not canonicalize the condition
+ further. If ALLOW_CC_MODE is nonzero, allow the condition returned
+ to be a compare to a CC mode register.
+
+ If VALID_AT_INSN_P, the condition must be valid at both *EARLIEST
+ and at INSN. */
+
+rtx
+canonicalize_condition (rtx insn, rtx cond, int reverse, rtx *earliest,
+ rtx want_reg, int allow_cc_mode, int valid_at_insn_p)
+{
+ enum rtx_code code;
+ rtx prev = insn;
+ rtx set;
+ rtx tem;
+ rtx op0, op1;
+ int reverse_code = 0;
+ enum machine_mode mode;
+
+ code = GET_CODE (cond);
+ mode = GET_MODE (cond);
+ op0 = XEXP (cond, 0);
+ op1 = XEXP (cond, 1);
+
+ if (reverse)
+ code = reversed_comparison_code (cond, insn);
+ if (code == UNKNOWN)
+ return 0;
+
+ if (earliest)
+ *earliest = insn;
+
+ /* If we are comparing a register with zero, see if the register is set
+ in the previous insn to a COMPARE or a comparison operation. Perform
+ the same tests as a function of STORE_FLAG_VALUE as find_comparison_args
+ in cse.c */
+
+ while ((GET_RTX_CLASS (code) == RTX_COMPARE
+ || GET_RTX_CLASS (code) == RTX_COMM_COMPARE)
+ && op1 == CONST0_RTX (GET_MODE (op0))
+ && op0 != want_reg)
+ {
+ /* Set nonzero when we find something of interest. */
+ rtx x = 0;
+
+#ifdef HAVE_cc0
+ /* If comparison with cc0, import actual comparison from compare
+ insn. */
+ if (op0 == cc0_rtx)
+ {
+ if ((prev = prev_nonnote_insn (prev)) == 0
+ || !NONJUMP_INSN_P (prev)
+ || (set = single_set (prev)) == 0
+ || SET_DEST (set) != cc0_rtx)
+ return 0;
+
+ op0 = SET_SRC (set);
+ op1 = CONST0_RTX (GET_MODE (op0));
+ if (earliest)
+ *earliest = prev;
+ }
+#endif
+
+ /* If this is a COMPARE, pick up the two things being compared. */
+ if (GET_CODE (op0) == COMPARE)
+ {
+ op1 = XEXP (op0, 1);
+ op0 = XEXP (op0, 0);
+ continue;
+ }
+ else if (!REG_P (op0))
+ break;
+
+ /* Go back to the previous insn. Stop if it is not an INSN. We also
+ stop if it isn't a single set or if it has a REG_INC note because
+ we don't want to bother dealing with it. */
+
+ if ((prev = prev_nonnote_insn (prev)) == 0
+ || !NONJUMP_INSN_P (prev)
+ || FIND_REG_INC_NOTE (prev, NULL_RTX))
+ break;
+
+ set = set_of (op0, prev);
+
+ if (set
+ && (GET_CODE (set) != SET
+ || !rtx_equal_p (SET_DEST (set), op0)))
+ break;
+
+ /* If this is setting OP0, get what it sets it to if it looks
+ relevant. */
+ if (set)
+ {
+ enum machine_mode inner_mode = GET_MODE (SET_DEST (set));
+#ifdef FLOAT_STORE_FLAG_VALUE
+ REAL_VALUE_TYPE fsfv;
+#endif
+
+ /* ??? We may not combine comparisons done in a CCmode with
+ comparisons not done in a CCmode. This is to aid targets
+ like Alpha that have an IEEE compliant EQ instruction, and
+ a non-IEEE compliant BEQ instruction. The use of CCmode is
+ actually artificial, simply to prevent the combination, but
+ should not affect other platforms.
+
+ However, we must allow VOIDmode comparisons to match either
+ CCmode or non-CCmode comparison, because some ports have
+ modeless comparisons inside branch patterns.
+
+ ??? This mode check should perhaps look more like the mode check
+ in simplify_comparison in combine. */
+
+ if ((GET_CODE (SET_SRC (set)) == COMPARE
+ || (((code == NE
+ || (code == LT
+ && GET_MODE_CLASS (inner_mode) == MODE_INT
+ && (GET_MODE_BITSIZE (inner_mode)
+ <= HOST_BITS_PER_WIDE_INT)
+ && (STORE_FLAG_VALUE
+ & ((HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (inner_mode) - 1))))
+#ifdef FLOAT_STORE_FLAG_VALUE
+ || (code == LT
+ && GET_MODE_CLASS (inner_mode) == MODE_FLOAT
+ && (fsfv = FLOAT_STORE_FLAG_VALUE (inner_mode),
+ REAL_VALUE_NEGATIVE (fsfv)))
+#endif
+ ))
+ && COMPARISON_P (SET_SRC (set))))
+ && (((GET_MODE_CLASS (mode) == MODE_CC)
+ == (GET_MODE_CLASS (inner_mode) == MODE_CC))
+ || mode == VOIDmode || inner_mode == VOIDmode))
+ x = SET_SRC (set);
+ else if (((code == EQ
+ || (code == GE
+ && (GET_MODE_BITSIZE (inner_mode)
+ <= HOST_BITS_PER_WIDE_INT)
+ && GET_MODE_CLASS (inner_mode) == MODE_INT
+ && (STORE_FLAG_VALUE
+ & ((HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (inner_mode) - 1))))
+#ifdef FLOAT_STORE_FLAG_VALUE
+ || (code == GE
+ && GET_MODE_CLASS (inner_mode) == MODE_FLOAT
+ && (fsfv = FLOAT_STORE_FLAG_VALUE (inner_mode),
+ REAL_VALUE_NEGATIVE (fsfv)))
+#endif
+ ))
+ && COMPARISON_P (SET_SRC (set))
+ && (((GET_MODE_CLASS (mode) == MODE_CC)
+ == (GET_MODE_CLASS (inner_mode) == MODE_CC))
+ || mode == VOIDmode || inner_mode == VOIDmode))
+
+ {
+ reverse_code = 1;
+ x = SET_SRC (set);
+ }
+ else
+ break;
+ }
+
+ else if (reg_set_p (op0, prev))
+ /* If this sets OP0, but not directly, we have to give up. */
+ break;
+
+ if (x)
+ {
+ /* If the caller is expecting the condition to be valid at INSN,
+ make sure X doesn't change before INSN. */
+ if (valid_at_insn_p)
+ if (modified_in_p (x, prev) || modified_between_p (x, prev, insn))
+ break;
+ if (COMPARISON_P (x))
+ code = GET_CODE (x);
+ if (reverse_code)
+ {
+ code = reversed_comparison_code (x, prev);
+ if (code == UNKNOWN)
+ return 0;
+ reverse_code = 0;
+ }
+
+ op0 = XEXP (x, 0), op1 = XEXP (x, 1);
+ if (earliest)
+ *earliest = prev;
+ }
+ }
+
+ /* If constant is first, put it last. */
+ if (CONSTANT_P (op0))
+ code = swap_condition (code), tem = op0, op0 = op1, op1 = tem;
+
+ /* If OP0 is the result of a comparison, we weren't able to find what
+ was really being compared, so fail. */
+ if (!allow_cc_mode
+ && GET_MODE_CLASS (GET_MODE (op0)) == MODE_CC)
+ return 0;
+
+ /* Canonicalize any ordered comparison with integers involving equality
+ if we can do computations in the relevant mode and we do not
+ overflow. */
+
+ if (GET_MODE_CLASS (GET_MODE (op0)) != MODE_CC
+ && GET_CODE (op1) == CONST_INT
+ && GET_MODE (op0) != VOIDmode
+ && GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT)
+ {
+ HOST_WIDE_INT const_val = INTVAL (op1);
+ unsigned HOST_WIDE_INT uconst_val = const_val;
+ unsigned HOST_WIDE_INT max_val
+ = (unsigned HOST_WIDE_INT) GET_MODE_MASK (GET_MODE (op0));
+
+ switch (code)
+ {
+ case LE:
+ if ((unsigned HOST_WIDE_INT) const_val != max_val >> 1)
+ code = LT, op1 = gen_int_mode (const_val + 1, GET_MODE (op0));
+ break;
+
+ /* When cross-compiling, const_val might be sign-extended from
+ BITS_PER_WORD to HOST_BITS_PER_WIDE_INT */
+ case GE:
+ if ((HOST_WIDE_INT) (const_val & max_val)
+ != (((HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (GET_MODE (op0)) - 1))))
+ code = GT, op1 = gen_int_mode (const_val - 1, GET_MODE (op0));
+ break;
+
+ case LEU:
+ if (uconst_val < max_val)
+ code = LTU, op1 = gen_int_mode (uconst_val + 1, GET_MODE (op0));
+ break;
+
+ case GEU:
+ if (uconst_val != 0)
+ code = GTU, op1 = gen_int_mode (uconst_val - 1, GET_MODE (op0));
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ /* Never return CC0; return zero instead. */
+ if (CC0_P (op0))
+ return 0;
+
+ return gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
+}
+
+/* Given a jump insn JUMP, return the condition that will cause it to branch
+ to its JUMP_LABEL. If the condition cannot be understood, or is an
+ inequality floating-point comparison which needs to be reversed, 0 will
+ be returned.
+
+ If EARLIEST is nonzero, it is a pointer to a place where the earliest
+ insn used in locating the condition was found. If a replacement test
+ of the condition is desired, it should be placed in front of that
+ insn and we will be sure that the inputs are still valid. If EARLIEST
+ is null, the returned condition will be valid at INSN.
+
+ If ALLOW_CC_MODE is nonzero, allow the condition returned to be a
+ compare CC mode register.
+
+ VALID_AT_INSN_P is the same as for canonicalize_condition. */
+
+rtx
+get_condition (rtx jump, rtx *earliest, int allow_cc_mode, int valid_at_insn_p)
+{
+ rtx cond;
+ int reverse;
+ rtx set;
+
+ /* If this is not a standard conditional jump, we can't parse it. */
+ if (!JUMP_P (jump)
+ || ! any_condjump_p (jump))
+ return 0;
+ set = pc_set (jump);
+
+ cond = XEXP (SET_SRC (set), 0);
+
+ /* If this branches to JUMP_LABEL when the condition is false, reverse
+ the condition. */
+ reverse
+ = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump);
+
+ return canonicalize_condition (jump, cond, reverse, earliest, NULL_RTX,
+ allow_cc_mode, valid_at_insn_p);
+}
+
+\f
+/* Initialize non_rtx_starting_operands, which is used to speed up
+ for_each_rtx. */
+void
+init_rtlanal (void)
+{
+ int i;
+ for (i = 0; i < NUM_RTX_CODE; i++)
+ {
+ const char *format = GET_RTX_FORMAT (i);
+ const char *first = strpbrk (format, "eEV");
+ non_rtx_starting_operands[i] = first ? first - format : -1;
+ }
+}