------- Comment #5 from pinskia at gcc dot gnu dot org 2007-01-04 22:21 -------
I think this was exposed/caused by the mem-ssa and the specific DSE
optimization for aggregate DSE:
2006-12-11 Aldy Hernandez <[EMAIL PROTECTED]>
* tree-ssa-dse.c (aggregate_vardecl_d): New.
(dse_global_data): Add aggregate_vardecl field.
(dse_possible_dead_store_p): New.
Add prev_defvar variable.
Allow immediate uses and previous immediate uses to differ
if they are setting different parts of the whole.
(get_aggregate_vardecl): New.
(dse_record_partial_aggregate_store): New.
(dse_whole_aggregate_clobbered_p): New.
(dse_partial_kill_p): New.
(dse_optimize_stmt): Abstract code checking a possible dead store
into new function dse_possible_dead_store_p().
Call dse_maybe_record_aggregate_store().
When checking whether a STMT and its USE_STMT refer to the
same memory address, check also for partial kills that clobber
the whole.
Move some variable definitions to the block where they are used.
(aggregate_vardecl_hash): New.
(aggregate_vardecl_eq): New.
(aggregate_vardecl_free): New.
(aggregate_whole_store_p): New.
(tree_ssa_dse): Initialize and free aggregate_vardecl.
Mark which aggregate stores we care about.
I think we have:
info_1 = V_DEF<info_0(D)>
info = {};
...
info_2 = V_DEF<info_1(D)>
winetest_set_location (&"encode.c"[0], 2886);
Which thinks info is fully clobbered by winetest_set_location which is not
true.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |aldyh at gcc dot gnu dot
| |org, dnovillo at gcc dot gnu
| |dot org
Component|c |tree-optimization
GCC build triplet|i686-pc-linux-gnu |
GCC host triplet|i686-pc-linux-gnu |
GCC target triplet|i686-pc-linux-gnu |
Keywords| |wrong-code
Summary|tree-ssa-dse incorrectly |[4.3 Regression] tree-ssa-
|removes struct |dse incorrectly removes
|initialization |struct initialization
Target Milestone|--- |4.3.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30375
