From 9827f778db2e051f0803ef226ee3076fd7ef9d20 Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@redhat.com>
Date: Tue, 27 Nov 2001 14:09:10 -0800
Subject: [PATCH] unroll.c (loop_iterations): Move last change ...
* unroll.c (loop_iterations): Move last change ...
* doloop.c (doloop_modify_runtime): ... here.
From-SVN: r47387
---
gcc/ChangeLog | 5 +++++
gcc/doloop.c | 40 ++++++++++++++++++++++++++++++++++++++++
gcc/unroll.c | 35 -----------------------------------
3 files changed, 45 insertions(+), 35 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 00e613407a86..577c2a393bf1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2001-11-17 Richard Henderson <rth@redhat.com>
+
+ * unroll.c (loop_iterations): Move last change ...
+ * doloop.c (doloop_modify_runtime): ... here.
+
2001-11-17 Corey Minyard <minyard@acm.org>
Richard Henderson <rth@redhat.com>
diff --git a/gcc/doloop.c b/gcc/doloop.c
index 2b1317f900af..be232d63e6c8 100644
--- a/gcc/doloop.c
+++ b/gcc/doloop.c
@@ -596,6 +596,46 @@ doloop_modify_runtime (loop, iterations_max,
copy_rtx (neg_inc ? final_value : initial_value),
NULL_RTX, unsigned_p, OPTAB_LIB_WIDEN);
+ /* Some code transformations can result in code akin to
+
+ tmp = i + 1;
+ ...
+ goto scan_start;
+ top:
+ tmp = tmp + 1;
+ scan_start:
+ i = tmp;
+ if (i < n) goto top;
+
+ We'll have already detected this form of loop in scan_loop,
+ and set loop->top and loop->scan_start appropriately.
+
+ In this situation, we skip the increment the first time through
+ the loop, which results in an incorrect estimate of the number
+ of iterations. Adjust the difference to compensate. */
+ /* ??? Logically, it would seem this belongs in loop_iterations.
+ However, this causes regressions e.g. on x86 execute/20011008-3.c,
+ so I do not believe we've properly characterized the exact nature
+ of the problem. In the meantime, this fixes execute/20011126-2.c
+ on ia64 and some Ada front end miscompilation on ppc. */
+
+ if (loop->scan_start)
+ {
+ struct loop_ivs *ivs = LOOP_IVS (loop);
+ struct iv_class *bl
+ = REG_IV_CLASS (ivs, REGNO (loop_info->iteration_var));
+
+ if (INSN_LUID (bl->biv->insn) < INSN_LUID (loop->scan_start))
+ {
+ if (loop_dump_stream)
+ fprintf (loop_dump_stream,
+ "Doloop: Basic induction var skips initial incr.\n");
+
+ diff = expand_simple_binop (mode, PLUS, diff, increment, diff,
+ unsigned_p, OPTAB_LIB_WIDEN);
+ }
+ }
+
if (abs_inc * loop_info->unroll_number != 1)
{
int shift_count;
diff --git a/gcc/unroll.c b/gcc/unroll.c
index 35ce939f0122..4b7dd974925a 100644
--- a/gcc/unroll.c
+++ b/gcc/unroll.c
@@ -3706,41 +3706,6 @@ loop_iterations (loop)
if (initial_value == 0)
return 0;
- /* Some code transformations can result in code akin to
-
- tmp = i + 1;
- ...
- goto scan_start;
- top:
- tmp = tmp + 1;
- scan_start:
- i = tmp;
- if (i < n) goto top;
-
- We'll have already detected this form of loop in scan_loop,
- and set loop->top and loop->scan_start appropriately.
-
- In this situation, we skip the increment the first time through
- the loop, which results in an incorrect estimate of the number
- of iterations. Adjust the initial value to compensate. */
-
- if (loop->scan_start && loop->cont
- && INSN_LUID (loop->scan_start) < INSN_LUID (loop->cont)
- && INSN_LUID (bl->biv->insn) < INSN_LUID (loop->scan_start))
- {
- if (loop_dump_stream)
- fprintf (loop_dump_stream,
- "Loop iterations: Basic induction var skips initial incr.\n");
- if (GET_CODE (increment) != CONST_INT)
- {
- if (loop_dump_stream)
- fprintf (loop_dump_stream,
- "Loop iterations: Can't adjust with non-constant incr.\n");
- return 0;
- }
- initial_value = plus_constant (initial_value, -INTVAL (increment));
- }
-
unsigned_p = 0;
off_by_one = 0;
switch (comparison_code)
--
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