https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118026
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2024-12-13
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There are 2 issues with the source (I will file the not unswitching loop
seperately).
On the extra moves, it is due to pred_single_widen_add<mode> using early
clobber:
```
(define_insn "@pred_single_widen_add<mode>"
[(set (match_operand:VWEXTF 0 "register_operand" "=&vr,
&vr")
(if_then_else:VWEXTF
(unspec:<VM>
[(match_operand:<VM> 1 "vector_mask_operand"
"vmWc1,vmWc1")
(match_operand 5 "vector_length_operand" " rK,
rK")
(match_operand 6 "const_int_operand" " i,
i")
(match_operand 7 "const_int_operand" " i,
i")
(match_operand 8 "const_int_operand" " i,
i")
(match_operand 9 "const_int_operand" " i,
i")
(reg:SI VL_REGNUM)
(reg:SI VTYPE_REGNUM)
(reg:SI FRM_REGNUM)] UNSPEC_VPREDICATE)
(plus:VWEXTF
(float_extend:VWEXTF
(match_operand:<V_DOUBLE_TRUNC> 4 "register_operand" " vr,
vr"))
(match_operand:VWEXTF 3 "register_operand" " vr,
vr"))
(match_operand:VWEXTF 2 "vector_merge_operand" " vu,
0")))]
"TARGET_VECTOR"
"vfwadd.wv\t%0,%3,%4%p1"
[(set_attr "type" "vfwalu")
(set_attr "mode" "<V_DOUBLE_TRUNC>")
(set (attr "frm_mode")
(symbol_ref "riscv_vector::get_frm_mode (operands[9])"))])
```
I suspect it does not need an early clobber here since you need to match up
operand 2 to operand 0.
