https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113913
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2024-02-13 Keywords| |ra --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This looks like a subreg issue: ``` (insn 18 17 8 2 (set (reg:RVVM2SF 134 [ <retval> ]) (if_then_else:RVVM2SF (unspec:RVVMF16BI [ (const_vector:RVVMF16BI repeat [ (const_int 1 [0x1]) ]) (reg:DI 138) (const_int 2 [0x2]) repeated x2 (const_int 1 [0x1]) (reg:SI 66 vl) (reg:SI 67 vtype) ] UNSPEC_VPREDICATE) (const_vector:RVVM2SF repeat [ (const_double:SF 0.0 [0x0.0p+0]) ]) (unspec:RVVM2SF [ (reg:DI 0 zero) ] UNSPEC_VUNDEF))) "/app/example.c":12:10 3943 {*pred_broadcastrvvm2sf_imm} (expr_list:REG_DEAD (reg:DI 138) (expr_list:REG_DEAD (reg:SI 67 vtype) (expr_list:REG_DEAD (reg:SI 66 vl) (expr_list:REG_DEAD (reg:DI 0 zero) (expr_list:REG_EQUAL (const_vector:RVVM2SF repeat [ (const_double:SF 0.0 [0x0.0p+0]) ]) (nil))))))) (insn 8 18 9 2 (set (subreg:RVVM1SF (reg:RVVM2SF 134 [ <retval> ]) 0) (reg:RVVM1SF 139)) "/app/example.c":12:10 2591 {*movrvvm1sf_whole} (expr_list:REG_DEAD (reg:RVVM1SF 139) (nil))) (insn 9 8 13 2 (set (subreg:RVVM1SF (reg:RVVM2SF 134 [ <retval> ]) [16, 16]) (reg:RVVM1SF 140)) "/app/example.c":12:10 2591 {*movrvvm1sf_whole} (expr_list:REG_DEAD (reg:RVVM1SF 140) (nil))) ``` Confirmed. There are others like this too. Though I wonder if we emit: (clobber (reg:RVVM2SF 134 [ <retval> ])) When expanding __riscv_vcreate_v_f32m1_f32m2 and friends. If that might help. The other thing is init-reg gets in the way and adds: ``` (insn 17 16 18 2 (set (reg:DI 138) (unspec:DI [ (const_int 8 [0x8]) ] UNSPEC_VLMAX)) "/app/example.c":6:10 -1 (nil)) (insn 18 17 8 2 (set (reg:RVVM2HF 134 [ <retval> ]) (if_then_else:RVVM2HF (unspec:RVVMF8BI [ (const_vector:RVVMF8BI repeat [ (const_int 1 [0x1]) ]) (reg:DI 138) (const_int 2 [0x2]) repeated x2 (const_int 1 [0x1]) (reg:SI 66 vl) (reg:SI 67 vtype) ] UNSPEC_VPREDICATE) (const_vector:RVVM2HF repeat [ (const_double:HF 0.0 [0x0.0p+0]) ]) (unspec:RVVM2HF [ (reg:DI 0 zero) ] UNSPEC_VUNDEF))) "/app/example.c":6:10 -1 (expr_list:REG_EQUAL (const_vector:RVVM2HF repeat [ (const_double:HF 0.0 [0x0.0p+0]) ]) (nil))) ```