loop.c (strength_reduce): For derived givs, replace the giv this was derived from...

	* loop.c (strength_reduce): For derived givs, replace the
	giv this was derived from with its new_reg.
	(recombine_givs): Don't set new_reg for derived giv.
	And don't print it, print SUM instead.

From-SVN: r25289

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d4e3b4f8af368072648175cf7ad35c83dd87fed8..bdc71f9fb8295cb47624249b3de8e2ad23e81406 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+Fri Feb 19 01:45:06 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+       * loop.c (strength_reduce): For derived givs, replace the
+       giv this was derived from with its new_reg.
+       (recombine_givs): Don't set new_reg for derived giv.
+       And don't print it, print SUM instead.
+
 Thu Feb 18 15:52:49 1999  Jim Wilson  <wilson@cygnus.com>
 
        * m68kelf.h (ASM_RETURN_CASE_JUMP): Add 5200 support.

diff --git a/gcc/loop.c b/gcc/loop.c
index 932a72549bf5db3a04c6a42fc4c2501d5852ced5..a5ea970b95c8f6782e19d9031b91a6d3cc7c407e 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -4682,10 +4682,21 @@ strength_reduce (scan_start, end, loop_top, insn_count,
            {
              int auto_inc_opt = 0;
 
-             v->new_reg = gen_reg_rtx (v->mode);
+             /* If the code for derived givs immediately below has already
+                allocated a new_reg, we must keep it.  */
+             if (! v->new_reg)
+               v->new_reg = gen_reg_rtx (v->mode);
 
              if (v->derived_from)
                {
+                 struct induction *d = v->derived_from;
+
+                 /* In case d->dest_reg is not replaceable, we have
+                    to replace it in v->insn now.  */
+                 if (! d->new_reg)
+                   d->new_reg = gen_reg_rtx (d->mode);
+                 PATTERN (v->insn)
+                   = replace_rtx (PATTERN (v->insn), d->dest_reg, d->new_reg);
                  PATTERN (v->insn)
                    = replace_rtx (PATTERN (v->insn), v->dest_reg, v->new_reg);
                  if (bl->biv_count != 1)
@@ -7359,11 +7370,9 @@ recombine_givs (bl, loop_start, loop_end, unroll_p)
                   && GET_CODE (XEXP (sum, 1)) == CONST_INT)
                  || ! unroll_p)
              && validate_change (v->insn, &PATTERN (v->insn),
-                                 gen_rtx_SET (GET_MODE (v->dest_reg),
-                                              v->dest_reg, sum), 0))
+                                 gen_rtx_SET (VOIDmode, v->dest_reg, sum), 0))
            {
              v->derived_from = last_giv;
-             v->new_reg = v->dest_reg;
              life_end = stats[i].end_luid;
 
              if (loop_dump_stream)
@@ -7371,7 +7380,7 @@ recombine_givs (bl, loop_start, loop_end, unroll_p)
                  fprintf (loop_dump_stream,
                           "giv at %d derived from %d as ",
                           INSN_UID (v->insn), INSN_UID (last_giv->insn));
-                 print_rtl (loop_dump_stream, v->new_reg);
+                 print_rtl (loop_dump_stream, sum);
                  putc ('\n', loop_dump_stream);
                }
            }