https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115710
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |5.5.0
Summary|fortran complex abs does |[11/12/13/14/15 Regression]
|not vectorise |complex abs does not
| |vectorise
Target Milestone|--- |11.5
Keywords| |needs-bisection
Known to fail| |6.1.0
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So before forwprop3 we have:
```
_10 = REALPART_EXPR <*_3>;
_9 = IMAGPART_EXPR <*_3>;
_4 = COMPLEX_EXPR <_10, _9>;
_5 = cabs (_4);
_6 = _1 * 8;
_7 = b_14(D) + _6;
reassocpow_18 = __builtin_powi (_5, 2);
```
After we get:
```
_10 = REALPART_EXPR <*_3>;
_4 = *_3;
_9 = IMAGPART_EXPR <*_3>;
_5 = cabs (_4);
_6 = _1 * 8;
_7 = b_14(D) + _6;
reassocpow_18 = __builtin_powi (_5, 2);
```
Which undoes complex lowering.
But then powcabs does:
```
_10 = REALPART_EXPR <*_3>;
_4 = *_3;
_9 = IMAGPART_EXPR <*_3>;
cabs_8 = REALPART_EXPR <_4>;
cabs_17 = cabs_8 * cabs_8;
cabs_22 = IMAGPART_EXPR <_4>;
cabs_23 = cabs_22 * cabs_22;
cabs_24 = cabs_17 + cabs_23;
powroot_25 = __builtin_sqrt (cabs_24);
_5 = powroot_25;
_6 = _1 * 8;
_7 = b_14(D) + _6;
powmult_26 = _5 * _5;
reassocpow_18 = powmult_26;
*_7 = reassocpow_18;
```
Which redoes some of the complex lowering but misses undoing the undo of
COMPLEX_EXPR<REAL<*3>, IMAG<*3>> ...
This is a regression even as GCC 5 used to be able top vectorize it.
