https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106265
--- Comment #4 from Vineet Gupta <vineet.gupta at linux dot dev> ---
Going back to first dump (upstream 6abe341558a w/o riscv_rtx_costs() adj): the
3rd instruction addi is marking a2 REG_DEAD at 315 cprop.hardreg
--->8---- 314r.rnreg
(insn 2663 2662 1714 3 (set (reg:DI 13 a3 [2815])
(plus:DI (reg:DI 12 a2 [2816])
(const_int -2024 [0xfffffffffffff818]))) "rhs-cred.cc":42:47 4
{adddi3}
(expr_list:REG_EQUAL (const_int 2072 [0x818])
(nil)))
--->8---- 315r.cprop_hardreg
(insn 2663 2662 1714 3 (set (reg:DI 13 a3 [2815])
(plus:DI (reg:DI 12 a2 [2816])
(const_int -2024 [0xfffffffffffff818]))) "rhs-cred.cc":42:47 4
{adddi3}
(expr_list:REG_DEAD (reg:DI 12 a2 [2816])
(expr_list:REG_EQUAL (const_int 2072 [0x818])
(nil))))
Not sure if that is the issue or the compiler just deducing that a2 is dead
given that the next instruction sets it up again was introduced much earlier in
300r.reload
