[Bug target/36840] Fortran complex array multiply missed optimization

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2008-07-23 09:37 -------
The problem is that SLP and the reduction operation do not mix and that the
vectorizer doesn't understand the complex component accessors.

<bb 4>:
  # S.4_40 = PHI <S.4_33(5), 1(3)>
  D.1045_26 = S.4_40 + -1;
  CR.27_44 = REALPART_EXPR <(*iy_27(D))[D.1045_26]>;
  CI.28_45 = IMAGPART_EXPR <(*iy_27(D))[D.1045_26]>;
  CR.29_46 = REALPART_EXPR <(*ix_30(D))[D.1045_26]>;
  CI.30_47 = IMAGPART_EXPR <(*ix_30(D))[D.1045_26]>;
  D.1076_48 = CR.27_44 * CR.29_46;
  D.1077_49 = CI.28_45 * CI.30_47;
  D.1078_50 = CR.27_44 * CI.30_47;
  D.1079_51 = CI.28_45 * CR.29_46;
  CR.31_52 = D.1076_48 - D.1077_49;
  CI.32_53 = D.1078_50 + D.1079_51;
  REALPART_EXPR <(*iy_27(D))[D.1045_26]> = CR.31_52;
  IMAGPART_EXPR <(*iy_27(D))[D.1045_26]> = CI.32_53;
  S.4_33 = S.4_40 + 1;
  if (size.3_4 < S.4_33)

there are bugs about this already.

For the specific task of complex operations we can possibly change the
complex-lowering code to directly generate the vectorized equivalent,
though of course teaching the vectorizer to handle the above would be
more useful.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |irar at il dot ibm dot com
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-07-23 09:37:26
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36840