[Bug rtl-optimization/45685] [4.6 Regression] GCC optimizer for Intel x64 generates inefficient code

[matz at gcc dot gnu dot org]

------- Comment #7 from matz at gcc dot gnu dot org  2010-09-17 13:45 -------
It might have been exposed by that revision, but that merely points out
a deficiency in RTL if conversion.  The final gimple code doesn't have
explicit jumps in the inner loop, but uses cond_expr:

<bb 3>:
  # s_22 = PHI <0(2), s_30(3)>
  # i_19 = PHI <0(2), i_31(3)>
  D.2693_11 = MEM[base: products_9(D), index: i_19, step: 8, offset: 0B];
  val_4 = [cond_expr] D.2693_11 <= 0 ? -1 : 1;
  prephitmp.9_39 = [cond_expr] D.2693_11 <= 0 ? -1 : 1;
  prephitmp.10_40 = [cond_expr] D.2693_11 <= 0 ? 1 : -1;
  prephitmp.11_41 = [cond_expr] D.2693_11 <= 0 ? 1 : -1;
  D.2698_21 = D.2693_11 * prephitmp.9_39;
  D.2699_25 = (long unsigned int) D.2698_21;
  val_3 = [cond_expr] i_19 != D.2699_25 ? prephitmp.10_40 : val_4;
  prephitmp.11_43 = [cond_expr] i_19 != D.2699_25 ? prephitmp.11_41 :
prephitmp.9_39;
  MEM[base: products_9(D), index: i_19, step: 8, offset: 0B] = prephitmp.11_43;
  s_30 = val_3 + s_22;
  i_31 = i_19 + 1;
  if (i_31 != count_7(D))
    goto <bb 3>;
  else
    goto <bb 4>;


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45685