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| author | Michael Hayes <m.hayes@elec.canterbury.ac.nz> | 1998-12-15 20:31:18 +0000 |
|---|---|---|
| committer | Michael Hayes <m.hayes@gcc.gnu.org> | 1998-12-15 20:31:18 +0000 |
| commit | 35704c46616d00f048172abd4311521baa35044d (patch) | |
| tree | 9ef0e744d566ecaef9e587914a1a553ec59e674e /gcc/loop.c | |
| parent | c7dda1e388309a4fffe95c0903b1029c2669b20c (diff) | |
| download | gcc-35704c46616d00f048172abd4311521baa35044d.zip gcc-35704c46616d00f048172abd4311521baa35044d.tar.gz gcc-35704c46616d00f048172abd4311521baa35044d.tar.bz2 | |
loop.h (loop_info): New field 'vtop'.
* loop.h (loop_info): New field 'vtop'.
* loop.c (check_dbra_loop): Use loop_info->vtop rather than
scanning loop for vtop.
* unroll.c (subtract_reg_term, find_common_reg_term): New functions.
(loop_iterations): Use them to determine if loop has a constant
number of iterations. Set loop_info->vtop. Don't subtract
common reg term from initial_value and final_value if have a
do-while loop.
From-SVN: r24333
Diffstat (limited to 'gcc/loop.c')
| -rw-r--r-- | gcc/loop.c | 24 |
1 files changed, 2 insertions, 22 deletions
@@ -6867,7 +6867,6 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info) enum rtx_code cmp_code; int comparison_const_width; unsigned HOST_WIDE_INT comparison_sign_mask; - rtx vtop; add_val = INTVAL (bl->biv->add_val); comparison_value = XEXP (comparison, 1); @@ -6914,25 +6913,6 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info) initial_value = const0_rtx; } - /* Check if there is a NOTE_INSN_LOOP_VTOP note. If there is, - that means that this is a for or while style loop, with - a loop exit test at the start. Thus, we can assume that - the loop condition was true when the loop was entered. - This allows us to change the loop exit condition to an - equality test. - We start at the end and search backwards for the previous - NOTE. If there is no NOTE_INSN_LOOP_VTOP for this loop, - the search will stop at the NOTE_INSN_LOOP_CONT. */ - vtop = loop_end; - do - vtop = PREV_INSN (vtop); - while (GET_CODE (vtop) != NOTE - || NOTE_LINE_NUMBER (vtop) > 0 - || NOTE_LINE_NUMBER (vtop) == NOTE_REPEATED_LINE_NUMBER - || NOTE_LINE_NUMBER (vtop) == NOTE_INSN_DELETED); - if (NOTE_LINE_NUMBER (vtop) != NOTE_INSN_LOOP_VTOP) - vtop = NULL_RTX; - /* First check if we can do a vanilla loop reversal. */ if (initial_value == const0_rtx /* If we have a decrement_and_branch_on_count, prefer @@ -6941,7 +6921,7 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info) reversal if the biv is used to calculate a giv or has a non-counting use. */ #if ! defined (HAVE_decrement_and_branch_until_zero) && defined (HAVE_decrement_and_branch_on_count) - && (! (add_val == 1 && vtop + && (! (add_val == 1 && loop_info->vtop && (bl->biv_count == 0 || no_use_except_counting))) #endif @@ -6956,7 +6936,7 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info) nonneg = 1; cmp_code = GE; } - else if (add_val == 1 && vtop + else if (add_val == 1 && loop_info->vtop && (bl->biv_count == 0 || no_use_except_counting)) { |