+Thu Nov 26 17:49:29 1998 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
+
+ * loop.c (check_dbra_loop): Update JUMP_LABEL field of jump insn
+ when loop reversed.
+
+ * unroll.c (precondition_loop_p): Return loop_initial_value
+ for initial_value instead of loop_iteration_var.
+
Thu Nov 26 17:15:38 1998 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
* config/c4x/c4x.md: Fix minor formatting problems. Update docs.
end_sequence ();
emit_jump_insn_before (tem, loop_end);
+ for (tem = PREV_INSN (loop_end);
+ tem && GET_CODE (tem) != JUMP_INSN;
+ tem = PREV_INSN (tem))
+ ;
+
+ if (tem)
+ JUMP_LABEL (tem) = XEXP (jump_label, 0);
+
if (nonneg)
{
- for (tem = PREV_INSN (loop_end);
- tem && GET_CODE (tem) != JUMP_INSN;
- tem = PREV_INSN (tem))
- ;
if (tem)
{
- JUMP_LABEL (tem) = XEXP (jump_label, 0);
-
/* Increment of LABEL_NUSES done above. */
/* Register is now always nonnegative,
so add REG_NONNEG note to the branch. */
return 0;
}
- /* Now set initial_value to be the iteration_var, since that may be a
- simpler expression, and is guaranteed to be correct if all of the
- above tests succeed.
-
- We can not use the initial_value as calculated, because it will be
- one too small for loops of the form "while (i-- > 0)". We can not
- emit code before the loop_skip_over insns to fix this problem as this
- will then give a number one too large for loops of the form
- "while (--i > 0)".
-
- Note that all loops that reach here are entered at the top, because
- this function is not called if the loop starts with a jump. */
-
/* Fail if loop_iteration_var is not live before loop_start, since we need
to test its value in the preconditioning code. */
return 0;
}
- *initial_value = loop_iteration_var;
+ /* ??? Note that if iteration_info is modifed to allow GIV iterators
+ such as "while (i-- > 0)", the initial value will be one too small.
+ In this case, loop_iteration_var could be used to determine
+ the correct initial value, provided the loop has not been reversed.
+
+ Also note that the absolute values of initial_value and
+ final_value are unimportant as only their difference is used for
+ calculating the number of loop iterations. */
+ *initial_value = loop_initial_value;
*increment = loop_increment;
*final_value = loop_final_value;