target.h (gcc_target): Add cannot_force_const_mem.

target.h (gcc_target): Add cannot_force_const_mem.

        * target.h (gcc_target): Add cannot_force_const_mem.
        * target-def.h (TARGET_CANNOT_FORCE_CONST_MEM): New.
        (TARGET_INITIALIZER): Add it.
        * varasm.c (force_const_mem): Fail if cannot_force_const_mem.
        * expr.c (emit_move_insn): Be prepared for force_const_mem to fail.
        * reload1.c (reload): Likewise.
        * hooks.c (hook_bool_rtx_false): New.
        * hooks.h: Declare it.

        * config/i386/i386.c (ix86_cannot_force_const_mem): New.
        (TARGET_CANNOT_FORCE_CONST_MEM): New.
        (ix86_expand_move): Remove de-const-pooling hack.

	* gcc.dg/tls/opt-4.c: New.

From-SVN: r59971