The insn starts like this:
(insn 238 237 239 35 ../../../../../src/newlib/libc/stdio/vfprintf.c:604 (set
(reg/v:HI 175 [ ch ])
(sign_extend:HI (mem:QI (reg/v/f:HI 176 [ fmt ]) [0 S1 A8]))) 46
{extendqihi2} (nil)
(nil))
Reload 0: reload_in (HI) = (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
A_REGS, RELOAD_FOR_OUTPUT_ADDRESS (opnum = 0)
reload_in_reg: (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
Reload 1: reload_in (HI) = (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
A_REGS, RELOAD_FOR_INPADDR_ADDRESS (opnum = 1)
reload_in_reg: (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
Reload 2: reload_in (HI) = (mem/c:HI (plus:HI (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
(const_int -476
[0xfffffffffffffe24])) [108 fmt+0 S2 A8])
A_REGS, RELOAD_FOR_INPUT_ADDRESS (opnum = 1), can't combine
reload_in_reg: (reg/v/f:HI 176 [ fmt ])
Reload 3: reload_in (QI) = (mem:QI (reg/v/f:HI 176 [ fmt ]) [0 S1 A8])
reload_out (HI) = (mem/c:HI (plus:HI (plus:HI (reg/f:HI 7 fb)
(const_int -128
[0xffffffffffffff80]))
(const_int -474
[0xfffffffffffffe26])) [107 ch+0 S2 A8])
HL_REGS, RELOAD_OTHER (opnum = 0)
reload_in_reg: (mem:QI (reg/v/f:HI 176 [ fmt ]) [0 S1 A8])
reload_out_reg: (reg/v:HI 175 [ ch ])
And the md file:
(define_insn "extendqihi2"
[(set (match_operand:HI 0 "mra_operand" "=RhlSd*Rmm")
(sign_extend:HI (match_operand:QI 1 "mra_operand" "0")))]
""
"exts.b\t%1"
[(set_attr "flags" "sz")]
)
