http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50204
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011-08-27
CC| |rguenth at gcc dot gnu.org
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-27
08:13:12 UTC ---
This is because we have, for the 2nd load
<bb 6>:
# .MEM_4 = PHI <.MEM_7(3), .MEM_6(D)(4), .MEM_8(5)>
# VUSE <.MEM_4>
opening.0_3 = opening;
if (opening.0_3 != 4)
Thus three incoming edges. The walker in SCCVN does not try to handle
more than two, see tree-ssa-alias.c:get_continuation_for_phi ().
In principle one can handle N PHI arguments by reducing them to
N - 1 PHI arguments by handling two of them and reducing them to
the dominating continuation. And then iterate. But the idea of
get_continuation_for_phi () is to make this walk linear which it
wouldn't be for this case.
Confirmed anyway.
I suppose it's not performance critical for crafty to see this redundant
load?
