/* Loop optimization definitions for GNU C-Compiler
- Copyright (C) 1991 Free Software Foundation, Inc.
+ Copyright (C) 1991, 1995, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of GNU CC.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+#include "varray.h"
+#include "basic-block.h"
+
+/* Get the loop info pointer of a loop. */
+#define LOOP_INFO(LOOP) ((struct loop_info *) (LOOP)->aux)
/* Get the luid of an insn. Catch the error of trying to reference the LUID
of an insn added during loop, since these don't have LUIDs. */
For a DEST_ADDR type giv, this is 0. */
rtx *location; /* Place in the insn where this giv occurs.
If GIV_TYPE is DEST_REG, this is 0. */
+ /* For a biv, this is the place where add_val
+ was found. */
enum machine_mode mode; /* The mode of this biv or giv */
enum machine_mode mem_mode; /* For DEST_ADDR, mode of the memory object. */
rtx mult_val; /* Multiplicative factor for src_reg. */
final value could be calculated, it is put
here, and the giv is made replaceable. Set
the giv to this value before the loop. */
+ unsigned combined_with; /* The number of givs this giv has been
+ combined with. If nonzero, this giv
+ cannot combine with any other giv. */
unsigned replaceable : 1; /* 1 if we can substitute the strength-reduced
variable for the original variable.
0 means they must be kept separate and the
even if further info is available.
Both this and the above can be zero. */
unsigned ignore : 1; /* 1 prohibits further processing of giv */
- unsigned always_computable : 1;/* 1 if this set occurs each iteration */
+ unsigned always_computable : 1;/* 1 if this value is computable every
+ iteration. */
+ unsigned always_executed : 1; /* 1 if this set occurs each iteration. */
+ unsigned maybe_multiple : 1; /* Only used for a biv and 1 if this biv
+ update may be done multiple times per
+ iteration. */
unsigned cant_derive : 1; /* For giv's, 1 if this giv cannot derive
another giv. This occurs in many cases
where a giv's lifetime spans an update to
a biv. */
- unsigned combined_with : 1; /* 1 if this giv has been combined with. It
- then cannot combine with any other giv. */
unsigned maybe_dead : 1; /* 1 if this giv might be dead. In that case,
we won't use it to eliminate a biv, it
would probably lose. */
+ unsigned auto_inc_opt : 1; /* 1 if this giv had its increment output next
+ to it to try to form an auto-inc address. */
+ unsigned unrolled : 1; /* 1 if new register has been allocated and
+ initialized in unrolled loop. */
+ unsigned shared : 1;
+ unsigned no_const_addval : 1; /* 1 if add_val does not contain a const. */
+ unsigned multi_insn_incr : 1; /* 1 if multiple insns updated the biv. */
int lifetime; /* Length of life of this giv */
- int times_used; /* # times this giv is used. */
rtx derive_adjustment; /* If nonzero, is an adjustment to be
subtracted from add_val when this giv
derives another. This occurs when the
struct induction *same; /* If this giv has been combined with another
giv, this points to the base giv. The base
giv will have COMBINED_WITH non-zero. */
- int const_adjust; /* Used by loop unrolling, when an address giv
+ struct induction *derived_from;/* For a giv, if we decided to derive this
+ giv from another one. */
+ HOST_WIDE_INT const_adjust; /* Used by loop unrolling, when an address giv
is split, and a constant is eliminated from
the address, the -constant is stored here
for later use. */
+ int ix; /* Used by recombine_givs, as n index into
+ the stats array. */
+ struct induction *same_insn; /* If there are multiple identical givs in
+ the same insn, then all but one have this
+ field set, and they all point to the giv
+ that doesn't have this field set. */
+ rtx last_use; /* For a giv made from a biv increment, this is
+ a substitute for the lifetime information. */
};
/* A `struct iv_class' is created for each biv. */
rtx initial_value; /* Value of reg at loop start */
rtx initial_test; /* Test performed on BIV before loop */
struct iv_class *next; /* Links all class structures together */
- rtx init_insn; /* insn which intializes biv, 0 if none. */
+ rtx init_insn; /* insn which initializes biv, 0 if none. */
rtx init_set; /* SET of INIT_INSN, if any. */
unsigned incremented : 1; /* 1 if somewhere incremented/decremented */
unsigned eliminable : 1; /* 1 if plausible candidate for elimination. */
biv controls. */
};
+/* Information required to calculate the number of loop iterations.
+ This is set by loop_iterations. */
+
+struct loop_info
+{
+ /* Nonzero if there is a subroutine call in the current loop. */
+ int has_call;
+ /* Nonzero if there is a volatile memory reference in the current
+ loop. */
+ int has_volatile;
+ /* Nonzero if there is a tablejump in the current loop. */
+ int has_tablejump;
+ /* Nonzero if there are ways to leave the loop other than falling
+ off the end. */
+ int has_multiple_exit_targets;
+ /* Nonzero if there is an indirect jump in the current function. */
+ int has_indirect_jump;
+ /* Register or constant initial loop value. */
+ rtx initial_value;
+ /* Register or constant value used for comparison test. */
+ rtx comparison_value;
+ /* Register or constant approximate final value. */
+ rtx final_value;
+ /* Register or constant initial loop value with term common to
+ final_value removed. */
+ rtx initial_equiv_value;
+ /* Register or constant final loop value with term common to
+ initial_value removed. */
+ rtx final_equiv_value;
+ /* Register corresponding to iteration variable. */
+ rtx iteration_var;
+ /* Constant loop increment. */
+ rtx increment;
+ enum rtx_code comparison_code;
+ /* Holds the number of loop iterations. It is zero if the number
+ could not be calculated. Must be unsigned since the number of
+ iterations can be as high as 2^wordsize - 1. For loops with a
+ wider iterator, this number will be zero if the number of loop
+ iterations is too large for an unsigned integer to hold. */
+ unsigned HOST_WIDE_INT n_iterations;
+ /* The number of times the loop body was unrolled. */
+ unsigned int unroll_number;
+ int used_count_register;
+};
+
/* Definitions used by the basic induction variable discovery code. */
enum iv_mode { UNKNOWN_INDUCT, BASIC_INDUCT, NOT_BASIC_INDUCT,
GENERAL_INDUCT };
extern int *uid_luid;
extern int max_uid_for_loop;
-extern int *uid_loop_num;
-extern int *loop_outer_loop;
-extern rtx *loop_number_exit_labels;
-extern unsigned long loop_n_iterations;
extern int max_reg_before_loop;
-
+extern struct loop **uid_loop;
extern FILE *loop_dump_stream;
-extern enum iv_mode *reg_iv_type;
-extern struct induction **reg_iv_info;
+extern varray_type reg_iv_type;
+extern varray_type reg_iv_info;
+
+#define REG_IV_TYPE(n) \
+ (*(enum iv_mode *) &VARRAY_INT(reg_iv_type, (n)))
+#define REG_IV_INFO(n) \
+ (*(struct induction **) &VARRAY_GENERIC_PTR(reg_iv_info, (n)))
+
extern struct iv_class **reg_biv_class;
extern struct iv_class *loop_iv_list;
+extern int first_increment_giv, last_increment_giv;
+
/* Forward declarations for non-static functions declared in loop.c and
unroll.c. */
-int invariant_p ();
-rtx get_condition_for_loop ();
-void emit_iv_add_mult ();
-
-/* Variables declared in stmt.c but also needed in loop.c. */
-
-extern union tree_node **loop_number_first_block;
-extern union tree_node **loop_number_last_block;
-extern int *loop_number_block_level;
+int loop_invariant_p PARAMS ((const struct loop *, rtx));
+rtx get_condition_for_loop PARAMS ((const struct loop *, rtx));
+void emit_iv_add_mult PARAMS ((rtx, rtx, rtx, rtx, rtx));
+rtx express_from PARAMS ((struct induction *, struct induction *));
+
+void unroll_loop PARAMS ((struct loop *, int, rtx, int));
+rtx biv_total_increment PARAMS ((struct iv_class *));
+unsigned HOST_WIDE_INT loop_iterations PARAMS ((struct loop *));
+int precondition_loop_p PARAMS ((const struct loop *,
+ rtx *, rtx *, rtx *,
+ enum machine_mode *mode));
+rtx final_biv_value PARAMS ((const struct loop *, struct iv_class *));
+rtx final_giv_value PARAMS ((const struct loop *, struct induction *));
+void emit_unrolled_add PARAMS ((rtx, rtx, rtx));
+int back_branch_in_range_p PARAMS ((const struct loop *, rtx));
+
+int loop_insn_first_p PARAMS ((rtx, rtx));
/* Forward declarations for non-static functions declared in stmt.c. */
-void find_loop_tree_blocks ();
-void unroll_block_trees ();
-
-void unroll_loop ();
-rtx biv_total_increment ();
-unsigned long loop_iterations ();
-rtx final_biv_value ();
-rtx final_giv_value ();
-void emit_unrolled_add ();
+void find_loop_tree_blocks PARAMS ((void));
+void unroll_block_trees PARAMS ((void));
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