[Bug tree-optimization/24669] Loop index variable has offset of 1

[uros at kss-loka dot si]

------- Comment #3 from uros at kss-loka dot si  2005-11-04 12:19 -------
Following patch to ix86_address_cost:

--- i386.c      (revision 106482)
+++ i386.c      (working copy)
@@ -5396,8 +5396,12 @@
   if (parts.index && GET_CODE (parts.index) == SUBREG)
     parts.index = SUBREG_REG (parts.index);

+  /* Penalize displacements a bit.  */
+  if (parts.disp && parts.disp != const0_rtx)
+    cost++;
+
   /* More complex memory references are better.  */
-  if (parts.disp && parts.disp != const0_rtx)
+  if (parts.scale)
     cost--;
   if (parts.seg != SEG_DEFAULT)
     cost--;

generates:

        pushl   %ebx
        movl    8(%esp), %ebx
        movl    12(%esp), %ecx
        xorl    %edx, %edx
.L2:
        movl    (%ebx,%edx,4), %eax
        movl    %eax, (%ecx,%edx,4)
        addl    $1, %edx
        cmpl    $4, %edx
        jne     .L2
        popl    %ebx
        ret


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24669