gcc/
        * Makefile.in (OBJS-common): Add tree-ssa-alias-warnings.o.
        * c-common.c (strict_aliasing_warning): Modify -Wstrict-aliasing logic.
        * c-common.h (strict_aliasing_warning): Change return type.
        * c-opts.c (c_common_handle_option): Add call to set_Wstrict_aliasing.
        * c-typeck.c (build_indirect_ref): Add call to strict_aliasing_warning.
        (build_c_cast): Condition call to strict_aliasing_warning.
        * doc/invoke.texi: Update description of -Wstrict-aliasing[=n].
        * flags.h (set_Wstrict_aliasing): Declare.
        * opts.c (set_Wstrict_alising): Define, add call to.
        * tree-flow.h (strict_aliasing_warning_backend): Declare.
        * tree-ssa-alias-warnings.c: New file.
        * tree-ssa-alias.c (compute_may_aliases): Add call to
        strict_aliasing_warning_backend.

gcc/cp
        * cp/typeck.c (build_indirect_ref): Add call to
        strict_aliasing_warning.
        (build_reinterpret_cast_1): Condition call to
        strict_aliasing_warning.

gcc/testsuite
        * gcc.dg/Wstrict-aliasing-bogus-const-ptr-nonconst-ptr.c: New test.
        * gcc.dg/Wstrict-aliasing-bogus-never-dereferenced.c: New test.
        * gcc.dg/Wstrict-aliasing-bogus-struct-included.c: New test.
        * gcc.dg/Wstrict-aliasing-converted-assigned.c: New test.
        * gcc.dg/Wstrict-aliasing-float-ptr-int-obj.c: New test.
        * gcc.dg/alias-1.c: Update option: -Wstrict-aliasing=2.
        * gcc.dg/alias-9.c: Update option: -Wstrict-aliasing=2.
        * g++.dg/warn/Wstrict-aliasing-7.C: Update option: -Wstrict-aliasing=2.
        * g++.dg/warn/Wstrict-aliasing-bogus-base-derived.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-char-1.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-const.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-nested-arrays.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-signed-unsigned.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-struct-included.C: New test.
        * g++.dg/warn/Wstrict-aliasing-bogus-union.C: New test.
        * g++.dg/warn/Wstrict-aliasing-float-ref-int-obj.C: New test.

From-SVN: r124622