On 11/18/2015 05:52 PM, Bernd Schmidt wrote:
(This is on the RL78 target where HImode values occupy two hard
registers and QImode values only one. The bug however is generic, not
RL78 specific).
The REE pass transforms this into:
(insn 44 (set (reg:QI r11) (mem:QI (reg:HI r20)))
(insn 45 (set (reg:HI r10) (zero_extend:HI (mem:QI (reg:HI r18))))
[...]
(insn 71 (set (reg:HI r14) (zero_extend:HI (reg:QI r11)))
[...]
(insn 88 deleted)
Note how the new set at insn 45 clobbers the value loaded by insn 44
into r11.
I had a look around. There's code testing HARD_REGNO_NREGS in
ree.c:combine_set_extension. It's inside #if 0, and labelled
"temporarily disabled". See if enabling that helps you? (Jeff, that #if
0 was added by you).
I was going to dig into this discussion tomorrow since I was the last
one in that code. Just had to get that threading regression resolved
first :-)
jeff
