Reminder: delete_trivially_dead insns regression

[Joern RENNECKE]

The effectiveness of delete_trivially_dead_insns has been considerably 
reduced last year.
I have sent a patch here: 
http://gcc.gnu.org/ml/gcc-patches/2004-05/msg01037.html
which is still waiting for review.

2004-05-17  J"orn Rennecke <joern.rennecke@superh.com>

	Back out this patch:
	  2003-10-08  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
	  PR optimization/12142
	  * cse.c (count_reg_usage): In a SET with a REG SET_DEST, count the
	  uses of the register in the SET_SRC.  Remove unnecessary argument.

	Replace it with this:
	* cse.c (count_reg_usage): In INSN, JUMP_INSN and CALL_INSN cases,
	if flag_non_call_exceptions is set and the insn may trap, pass
	pc_rtx as dest for recursion.
	In SET_SRC part of SET case, if dest is already set, pass it down
	unchanged.