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loop-unroll.c (unroll_loop_runtime_iterations): Condition initial loop peel to loops with exit test at the beginning. 

* loop-unroll.c (unroll_loop_runtime_iterations): Condition initial
	loop peel to loops with exit test at the beginning.

From-SVN: r241173
This commit is contained in:
Pat Haugen 2016-10-14 17:21:19 +00:00 committed by Pat Haugen
parent db2fb304fe
commit de0a3fa38e
2 changed files with 31 additions and 15 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2016-10-14 Pat Haugen <pthaugen@us.ibm.com>
* loop-unroll.c (unroll_loop_runtime_iterations): Condition initial
loop peel to loops with exit test at the beginning.
2016-10-14 Pat Haugen <pthaugen@us.ibm.com> 2016-10-14 Pat Haugen <pthaugen@us.ibm.com>
PR rtl-optimization/68212 PR rtl-optimization/68212

25
gcc/loop-unroll.c
View File

@ -858,7 +858,7 @@ unroll_loop_runtime_iterations (struct loop *loop)
rtx old_niter, niter, tmp; rtx old_niter, niter, tmp;
rtx_insn *init_code, *branch_code; rtx_insn *init_code, *branch_code;
unsigned i, j, p; unsigned i, j, p;
basic_block preheader, *body, swtch, ezc_swtch; basic_block preheader, *body, swtch, ezc_swtch = NULL;
int may_exit_copy, iter_freq, new_freq; int may_exit_copy, iter_freq, new_freq;
gcov_type iter_count, new_count; gcov_type iter_count, new_count;
unsigned n_peel; unsigned n_peel;
@ -918,6 +918,16 @@ unroll_loop_runtime_iterations (struct loop *loop)
if (tmp != niter) if (tmp != niter)
emit_move_insn (niter, tmp); emit_move_insn (niter, tmp);
/* For loops that exit at end, add one to niter to account for first pass
through loop body before reaching exit test. */
if (exit_at_end)
{
niter = expand_simple_binop (desc->mode, PLUS,
niter, const1_rtx,
NULL_RTX, 0, OPTAB_LIB_WIDEN);
old_niter = niter;
}
/* Count modulo by ANDing it with max_unroll; we use the fact that /* Count modulo by ANDing it with max_unroll; we use the fact that
the number of unrollings is a power of two, and thus this is correct the number of unrollings is a power of two, and thus this is correct
even if there is overflow in the computation. */ even if there is overflow in the computation. */
@ -936,13 +946,13 @@ unroll_loop_runtime_iterations (struct loop *loop)
auto_sbitmap wont_exit (max_unroll + 2); auto_sbitmap wont_exit (max_unroll + 2);
/* Peel the first copy of loop body (almost always we must leave exit test if (extra_zero_check)
here; the only exception is when we have extra zero check and the number {
of iterations is reliable. Also record the place of (possible) extra /* Peel the first copy of loop body. Leave the exit test if the number
zero check. */ of iterations is not reliable. Also record the place of the extra zero
check. */
bitmap_clear (wont_exit); bitmap_clear (wont_exit);
if (extra_zero_check if (!desc->noloop_assumptions)
&& !desc->noloop_assumptions)
bitmap_set_bit (wont_exit, 1); bitmap_set_bit (wont_exit, 1);
ezc_swtch = loop_preheader_edge (loop)->src; ezc_swtch = loop_preheader_edge (loop)->src;
ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop), ok = duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
@ -950,6 +960,7 @@ unroll_loop_runtime_iterations (struct loop *loop)
&remove_edges, &remove_edges,
DLTHE_FLAG_UPDATE_FREQ); DLTHE_FLAG_UPDATE_FREQ);
gcc_assert (ok); gcc_assert (ok);
}
/* Record the place where switch will be built for preconditioning. */ /* Record the place where switch will be built for preconditioning. */
swtch = split_edge (loop_preheader_edge (loop)); swtch = split_edge (loop_preheader_edge (loop));