regcprop: Avoid DCE of asm goto [PR100590]

regcprop: Avoid DCE of asm goto [PR100590]

The following testcase ICEs, because copyprop_hardreg_forward_1 decides
to DCE asm goto with REG_UNUSED notes (because the output is unused and
asm isn't volatile).  But that DCE just removes the asm goto, leaving
a bb with two successors and no insn at the end that would allow that.

The following patch makes sure we drop that way only INSNs and not
JUMP_INSNs or CALL_INSNs.

2021-05-18  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/100590
	* regcprop.c (copyprop_hardreg_forward_1): Only DCE dead sets if
	they are NONJUMP_INSN_P.

	* gcc.dg/pr100590.c: New test.

(cherry picked from commit c81704b359283bb54696755ead881ab04136da94)