#include "flags.h"
#include "expr.h"
#include "loop.h"
+#include "toplev.h"
/* This controls which loops are unrolled, and by how much we unroll
them. */
/* Values describing the current loop's iteration variable. These are set up
by loop_iterations, and used by precondition_loop_p. */
-static rtx loop_iteration_var;
-static rtx loop_initial_value;
-static rtx loop_increment;
-static rtx loop_final_value;
-static enum rtx_code loop_comparison_code;
+rtx loop_iteration_var;
+rtx loop_initial_value;
+rtx loop_increment;
+rtx loop_final_value;
+enum rtx_code loop_comparison_code;
/* Forward declarations. */
static void init_reg_map PROTO((struct inline_remap *, int));
-static int precondition_loop_p PROTO((rtx *, rtx *, rtx *, rtx, rtx));
+static int precondition_loop_p PROTO((rtx *, rtx *, rtx *, rtx));
static rtx calculate_giv_inc PROTO((rtx, rtx, int));
static rtx initial_reg_note_copy PROTO((rtx, struct inline_remap *));
static void final_reg_note_copy PROTO((rtx, struct inline_remap *));
loop_n_iterations = 0;
if (loop_dump_stream && loop_n_iterations > 0)
- fprintf (loop_dump_stream,
- "Loop unrolling: %d iterations.\n", loop_n_iterations);
+ {
+ fputs ("Loop unrolling: ", loop_dump_stream);
+ fprintf (loop_dump_stream, HOST_WIDE_INT_PRINT_DEC, loop_n_iterations);
+ fputs (" iterations.\n", loop_dump_stream);
+ }
/* Find and save a pointer to the last nonnote insn in the loop. */
if (unroll_type == UNROLL_COMPLETELY || unroll_type == UNROLL_MODULO)
{
- /* Loops of these types should never start with a jump down to
- the exit condition test. For now, check for this case just to
- be sure. UNROLL_NAIVE loops can be of this form, this case is
- handled below. */
+ /* Loops of these types can start with jump down to the exit condition
+ in rare circumstances.
+
+ Consider a pair of nested loops where the inner loop is part
+ of the exit code for the outer loop.
+
+ In this case jump.c will not duplicate the exit test for the outer
+ loop, so it will start with a jump to the exit code.
+
+ Then consider if the inner loop turns out to iterate once and
+ only once. We will end up deleting the jumps associated with
+ the inner loop. However, the loop notes are not removed from
+ the instruction stream.
+
+ And finally assume that we can compute the number of iterations
+ for the outer loop.
+
+ In this case unroll may want to unroll the outer loop even though
+ it starts with a jump to the outer loop's exit code.
+
+ We could try to optimize this case, but it hardly seems worth it.
+ Just return without unrolling the loop in such cases. */
+
insn = loop_start;
while (GET_CODE (insn) != CODE_LABEL && GET_CODE (insn) != JUMP_INSN)
insn = NEXT_INSN (insn);
if (GET_CODE (insn) == JUMP_INSN)
- abort ();
+ return;
}
if (unroll_type == UNROLL_COMPLETELY)
for (insn = copy_start; insn != loop_end; insn = NEXT_INSN (insn))
{
+ rtx note;
+
if (GET_CODE (insn) == CODE_LABEL)
local_label[CODE_LABEL_NUMBER (insn)] = 1;
else if (GET_CODE (insn) == JUMP_INSN)
}
}
}
+ else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)))
+ set_label_in_map (map, CODE_LABEL_NUMBER (XEXP (note, 0)),
+ XEXP (note, 0));
}
/* Allocate space for the insn map. */
rtx initial_value, final_value, increment;
if (precondition_loop_p (&initial_value, &final_value, &increment,
- loop_start, loop_end))
+ loop_start))
{
register rtx diff ;
enum machine_mode mode;
/* Set unroll type to MODULO now. */
unroll_type = UNROLL_MODULO;
loop_preconditioned = 1;
-
-#ifdef HAIFA
- /* Fix the initial value for the loop as needed. */
- if (loop_n_iterations <= 0)
- loop_start_value [uid_loop_num [INSN_UID (loop_start)]]
- = initial_value;
-#endif
}
}
whether divide is cheap. */
static int
-precondition_loop_p (initial_value, final_value, increment, loop_start,
- loop_end)
+precondition_loop_p (initial_value, final_value, increment, loop_start)
rtx *initial_value, *final_value, *increment;
- rtx loop_start, loop_end;
+ rtx loop_start;
{
if (loop_n_iterations > 0)
*final_value = GEN_INT (loop_n_iterations);
if (loop_dump_stream)
- fprintf (loop_dump_stream,
- "Preconditioning: Success, number of iterations known, %d.\n",
- loop_n_iterations);
+ {
+ fputs ("Preconditioning: Success, number of iterations known, ",
+ loop_dump_stream);
+ fprintf (loop_dump_stream, HOST_WIDE_INT_PRINT_DEC,
+ loop_n_iterations);
+ fputs (".\n", loop_dump_stream);
+ }
return 1;
}
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