* gcse.c (reg_clear_last_set): New function.
(reg_set_info): If data is non-null, treat it as an sbitmap of
registers, set the bit for the register being set.
(compute_store_table): Allocate last_set_in with xcalloc.  Do not
memset this array on each iteration.  Pass reg_set_in_block[bb->index]
to note_stores while computing last_set_in instead of scanning
last_set_in after the first pass through the insns.
Clear last_set_in using reg_clear_last_set instead of explicitly
rescanning after each insn.  If checking is enabled, assert that
last_set_in is completely zeroed after each bb has been processed.

From-SVN: r74224