Mon May 11 17:43:03 1998 Jim Wilson <wilson@cygnus.com>
+ * regmove.c (fixup_match_2, find_matches, regmove_profitable):
+ Add explanatory comments.
+
* sparc.h (SPARC_INCOMING_INT_ARG_FIRST): Support TARGET_FLAT.
Mon May 11 17:24:27 1998 Richard Henderson <rth@cygnus.com>
return 0;
}
+/* INSN is adding a CONST_INT to a REG. We search backwards looking for
+ another add immediate instruction with the same source and dest registers,
+ and if we find one, we change INSN to an increment, and return 1. If
+ no changes are made, we return 0.
+
+ This changes
+ (set (reg100) (plus reg1 offset1))
+ ...
+ (set (reg100) (plus reg1 offset2))
+ to
+ (set (reg100) (plus reg1 offset1))
+ ...
+ (set (reg100) (plus reg100 offset2-offset1)) */
+
+/* ??? What does this comment mean? */
/* cse disrupts preincrement / postdecrement squences when it finds a
hard register as ultimate source, like the frame pointer. */
+
int
fixup_match_2 (insn, dst, src, offset, regmove_dump_file)
rtx insn, dst, src, offset;
#endif /* REGISTER_CONSTRAINTS */
}
+/* Returns the INSN_CODE for INSN if its pattern has matching constraints for
+ any operand. Returns -1 if INSN can't be recognized, or if the alternative
+ can't be determined.
+
+ Initialize the info in MATCHP based on the constraints. */
static int
find_matches (insn, matchp)
}
}
-/* Test if regmove seems profitable for this target. */
+/* Test if regmove seems profitable for this target. Regmove is useful only
+ if some common patterns are two address, i.e. require matching constraints,
+ so we check that condition here. */
+
int
regmove_profitable_p ()
{