https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117860
--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Andrew Pinski from comment #1)
> Confirmed.
>
> I think it should be easy to support it with a slight change to this pattern:
> ```
> (define_insn "addcarry<mode>"
> [(set (reg:CCC FLAGS_REG)
> (compare:CCC
> (zero_extend:<DWI>
> (plus:SWI48
> (plus:SWI48
> (match_operator:SWI48 5 "ix86_carry_flag_operator"
> [(match_operand 3 "flags_reg_operand") (const_int 0)])
> (match_operand:SWI48 1 "nonimmediate_operand" "%0,0,rm,r"))
> (match_operand:SWI48 2 "nonimmediate_operand" "r,rm,r,m")))
> (plus:<DWI>
> (zero_extend:<DWI> (match_dup 2))
> (match_operator:<DWI> 4 "ix86_carry_flag_operator"
> [(match_dup 3) (const_int 0)]))))
> (set (match_operand:SWI48 0 "nonimmediate_operand" "=rm,r,r,r")
> (plus:SWI48 (plus:SWI48 (match_op_dup 5
> [(match_dup 3) (const_int 0)])
> (match_dup 1))
> (match_dup 2)))]
> "ix86_binary_operator_ok (PLUS, <MODE>mode, operands, TARGET_APX_NDD)"
> "@
> adc{<imodesuffix>}\t{%2, %0|%0, %2}
> adc{<imodesuffix>}\t{%2, %0|%0, %2}
> adc{<imodesuffix>}\t{%2, %1, %0|%0, %1, %2}
> adc{<imodesuffix>}\t{%2, %1, %0|%0, %1, %2}"
> [(set_attr "isa" "*,*,apx_ndd,apx_ndd")
> (set_attr "type" "alu")
> (set_attr "use_carry" "1")
> (set_attr "pent_pair" "pu")
> (set_attr "mode" "<MODE>")])
> ```
>
>
> operand 2 would need to change.
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index ffbb10730c0..f91cb97232a 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -9034,7 +9034,7 @@ (define_insn "addcarry<mode>"
(match_operator:SWI48 5 "ix86_carry_flag_operator"
[(match_operand 3 "flags_reg_operand") (const_int 0)])
(match_operand:SWI48 1 "nonimmediate_operand" "%0,0,rm,r"))
- (match_operand:SWI48 2 "nonimmediate_operand" "r,rm,r,m")))
+ (match_operand:SWI48 2 "x86_64_general_operand" "r,rme,r,me")))
(plus:<DWI>
(zero_extend:<DWI> (match_dup 2))
(match_operator:<DWI> 4 "ix86_carry_flag_operator"
The above does not work, because:
Trying 15 -> 19:
15: r112:DI=0x5
19:
{flags:CCC=cmp(zero_extend(ltu(flags:CCC,0)+r107:DI+r112:DI),zero_extend(r112:DI)+ltu(flags:CCC,0));r114:DI=ltu(flags:CCC,0)+r107:DI+r112:DI;}
REG_DEAD r112:DI
REG_DEAD r107:DI
Failed to match this instruction:
(parallel [
(set (reg:CC 17 flags)
(compare:CC (plus:TI (ltu:TI (reg:CCC 17 flags)
(const_int 0 [0]))
(const_int 5 [0x5]))
(zero_extend:TI (plus:DI (plus:DI (ltu:DI (reg:CCC 17 flags)
(const_int 0 [0]))
(reg/v:DI 107 [ a_hi ]))
(const_int 5 [0x5])))))
(set (reg:DI 114)
(plus:DI (plus:DI (ltu:DI (reg:CCC 17 flags)
(const_int 0 [0]))
(reg/v:DI 107 [ a_hi ]))
(const_int 5 [0x5])))
])
Combine creates (compare:CC) from (compare:CCC) RTX even for simple constant
propagation and fails instruction match.
(BTW: I'm not sure APX constraints are correct).
