[Bug tree-optimization/62112] Optimize out malloc when block is unused or write-only

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62112

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
Author: glisse
Date: Thu Aug 21 09:32:21 2014
New Revision: 214262

URL: https://gcc.gnu.org/viewcvs?rev=214262&root=gcc&view=rev
Log:
2014-08-21  Marc Glisse  <marc.glisse@inria.fr>

    PR tree-optimization/62112
gcc/
    * gimple-iterator.c (gsi_replace): Return whether EH cleanup is needed.
    * gimple-iterator.h (gsi_replace): Return bool.
    * tree-ssa-alias.c (ref_may_alias_global_p_1): New helper, code
    moved from ref_may_alias_global_p.
    (ref_may_alias_global_p, refs_may_alias_p, ref_maybe_used_by_stmt_p):
    New overloads.
    (ref_maybe_used_by_call_p): Take ao_ref* instead of tree.
    (stmt_kills_ref_p_1): Rename...
    (stmt_kills_ref_p): ... to this.
    * tree-ssa-alias.h (ref_may_alias_global_p, ref_maybe_used_by_stmt_p,
    stmt_kills_ref_p): Declare.
    * tree-ssa-dse.c (dse_possible_dead_store_p): New argument, use it.
    Move the self-assignment case...
    (dse_optimize_stmt): ... here. Handle builtin calls. Remove dead code.
gcc/testsuite/
    * gcc.dg/tree-ssa/pr62112-1.c: New file.
    * gcc.dg/tree-ssa/pr62112-2.c: Likewise.
    * gcc.c-torture/execute/pr35472.c: Add noclone attribute.
    * gcc.c-torture/execute/20071219-1.c: Likewise.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr62112-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr62112-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-iterator.c
    trunk/gcc/gimple-iterator.h
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.c-torture/execute/20071219-1.c
    trunk/gcc/testsuite/gcc.c-torture/execute/pr35472.c
    trunk/gcc/tree-ssa-alias.c
    trunk/gcc/tree-ssa-alias.h
    trunk/gcc/tree-ssa-dse.c