* unwind-dw2.c (_Unwind_GetGR): Honor DWARF_ZERO_REG.
        * doc/tm.texi (DWARF_ZERO_REG): New.
        * config/alpha/alpha.c (alpha_sa_mask, alpha_expand_prologue,
        alpha_expand_epilogue): Revert 2003-09-30 change to store zero.
        * config/alpha/alpha.h (DWARF_ZERO_REG): New.

From-SVN: r88331