loop.c (strength_reduce): Grow set_in_loop / n_times_set / may_not_optimize to proper...

	* loop.c (strength_reduce): Grow set_in_loop / n_times_set /
	may_not_optimize to proper size when converting biv increments
	into givs.
	If necessary, reallocate reg_iv_type / reg_iv_info before calling
	recombine_givs.

From-SVN: r24898

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3edd78099076df8382f0587d89a94e08a03ab1a5..338352e29e2416f28cd68c3fd3f6683372adb54a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+Fri Jan 29 00:14:55 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+       * loop.c (strength_reduce): Grow set_in_loop / n_times_set /
+       may_not_optimize to proper size when converting biv increments
+       into givs.
+       If necessary, reallocate reg_iv_type / reg_iv_info before calling
+       recombine_givs.
+
 Thu Jan 28 23:24:08 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
 
        * loop.c (recombine_givs): New parameter unroll_p.  If set, don't

diff --git a/gcc/loop.c b/gcc/loop.c
index a19bf38149d4de6c7320ad6dd04f8ada19fab10d..1acbb33ab1cf72091d52fb1dff2a8b8341b312ba 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -4143,11 +4143,13 @@ strength_reduce (scan_start, end, loop_top, insn_count,
              old_reg = v->dest_reg;
              dest_reg = gen_reg_rtx (v->mode);
     
+             /* Unlike reg_iv_type / reg_iv_info, the other three arrays
+                have been allocated with some slop space, so we may not
+                actually need to reallocate them.  If we do, the following
+                if statement will be executed just once in this loop.  */
              if ((unsigned) max_reg_num () > n_times_set->num_elements)
                {
-                 int nregs = max_reg_before_loop + n_extra_increment;
-    
-                 /* Grow all the arrays.  */
+                 /* Grow all the remaining arrays.  */
                  VARRAY_GROW (set_in_loop, nregs);
                  VARRAY_GROW (n_times_set, nregs);
                  VARRAY_GROW (may_not_optimize, nregs);
@@ -4431,6 +4433,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
       int benefit;
       int all_reduced;
       rtx final_value = 0;
+      unsigned nregs;
 
       /* Test whether it will be possible to eliminate this biv
         provided all givs are reduced.  This is possible if either
@@ -4582,7 +4585,22 @@ strength_reduce (scan_start, end, loop_top, insn_count,
        }
 
       /* Now that we know which givs will be reduced, try to rearrange the
-         combinations to reduce register pressure.  */
+         combinations to reduce register pressure.
+         recombine_givs calls find_life_end, which needs reg_iv_type and
+        reg_iv_info to be valid for all pseudos.  We do the necessary
+        reallocation here since it allows to check if there are still
+        more bivs to process.  */
+      nregs = max_reg_num ();
+      if (nregs > reg_iv_type->num_elements)
+       {
+         /* If there are still more bivs to process, allocate some slack
+            space so that we're not constantly reallocating these arrays.  */
+         if (bl->next)
+           nregs += nregs / 4;
+         /* Reallocate reg_iv_type and reg_iv_info.  */
+         VARRAY_GROW (reg_iv_type, nregs);
+         VARRAY_GROW (reg_iv_info, nregs);
+       }
       recombine_givs (bl, loop_start, loop_end, unroll_p);
 
       /* Reduce each giv that we decided to reduce.  */