Hello!
As described in great detail in PR 31966, Comment #7 and Comment #6,
there is a nasty bug in tree-if-convert.c. When a bb with condition
code directly feeds bb with a phi node, current implementation
"forgets" to account for the condition for the branch that leads to
the phi node [see PR for further explanation and for the proof].
The patch fixes this by attaching a condition of true or false arm to
relevant edge. When constructing equivalent condition for phi node,
incoming edges are checked if there is a condition attached to them,
and in this case equivalent condition is constructed by boolean AND of
successor block predicate and edge condition.
The patch has been checked on i686-pc-linux-gnu on gcc-41 and gcc-42
branches, as well as mainline, for all default languages. It fixes two
PRs and (as reported in PR32533) fixes a bunch of failing CP2K
testcases.
OK for mainline and 4.1 and 4.2 branch?
2007-07-02 Uros Bizjak <ubizjak@gmail.com>
PR tree-optimization/31966
PR tree-optimization/32533
* tree-if-conv.c (add_to_dst_predicate_list): Use "edge", not
"basic_block" description as its third argument. Update function
calls to get destination bb from "edge" argument. Save "cond" into
aux field of the edge. Update prototype for changed arguments.
(find_phi_replacement_condition): Operate on incoming edges, not
on predecessor blocks. If there is a condition saved in the
incoming edge aux field, AND it with incoming bb predicate.
Return source bb of the first edge.
(clean_predicate_lists): Clean aux field of outgoing node edges.
(tree_if_conversion): Do not initialize cond variable. Move
variable declaration into the loop.
(replace_phi_with_cond_gimple_modify_stmt): Remove unneded
initializations of new_stmt, arg0 and arg1 variables.
testsuite/ChangeLog:
2007-07-02 Uros Bizjak <ubizjak@gmail.com>
PR tree-optimization/31966
PR tree-optimization/32533
* gcc.dg/tree-ssa/pr31966.c: New runtime test.
* gfortran.dg/pr32533.f90: Ditto.
Uros.