Data Fields
struct reg_use	reg_use [RELOAD_COMBINE_MAX_USES]
rtx	offset
int	use_index
int	store_ruid
int	real_store_ruid
int	use_ruid
bool	all_offsets_match
rtx	expr

Detailed Description

If the register is used in some unknown fashion, USE_INDEX is negative.
If it is dead, USE_INDEX is RELOAD_COMBINE_MAX_USES, and STORE_RUID
indicates where it is first set or clobbered.
Otherwise, USE_INDEX is the index of the last encountered use of the
register (which is first among these we have seen since we scan backwards).
USE_RUID indicates the first encountered, i.e. last, of these uses.
If ALL_OFFSETS_MATCH is true, all encountered uses were inside a PLUS
with a constant offset; OFFSET contains this constant in that case.
STORE_RUID is always meaningful if we only want to use a value in a
register in a different place: it denotes the next insn in the insn
stream (i.e. the last encountered) that sets or clobbers the register.
REAL_STORE_RUID is similar, but clobbers are ignored when updating it.
EXPR is the expression used when storing the register.