[Bug rtl-optimization/18420] [4.0 Regression] ICE compiling mesa at -O2

[wilson at gcc dot gnu dot org]

------- Additional Comments From wilson at gcc dot gnu dot org  2004-11-11 05:19 -------
This looks like the same problem as 18294 which is an ia64-hpux bootstrap
failure.  In that PR, I suggested that simplify_gen_subreg should just create
the subreg for a hard register when simplify_subreg does not, but I haven't
looked at this very closely.  This problem occurs early, during virtual register
instantiation.

The patch in comment #11 is flawed.  It has
+          && GET_MODE_SIZE (innermode) != GET_MODE_SIZE (innermode)))
which will always be false.  Probably one of these was meant to be outermode.

If we are trying to prevent reload from creating subregs, then maybe the
reload_completed check could instead be !reload_in_progress.  This is just a
random guess though.  I haven't tried looking at Ulrich Weigand's patch yet.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18420