https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111334
--- Comment #16 from chenglulu <chenglulu at loongson dot cn> ---
(In reply to Xi Ruoyao from comment #15)
> (In reply to chenglulu from comment #13)
> > (In reply to Xi Ruoyao from comment #12)
> > > (In reply to chenglulu from comment #11)
> > > > (In reply to Xi Ruoyao from comment #10)
> > > > > (In reply to Xi Ruoyao from comment #9)
> > > > >
> > > > > > (define_insn "<optab>di3_fake"
> > > > > > [(set (match_operand:DI 0 "register_operand" "=r,&r,&r")
> > > > > > - (sign_extend:DI
> > > > > > - (any_div:SI (match_operand:DI 1 "register_operand" "r,r,0")
> > > > > > - (match_operand:DI 2 "register_operand"
> > > > > > "r,r,r"))))]
> > > > > > - ""
> > > > > > + (if_then_else
> > > > > > + (and (eq (match_operand:DI 1 "register_operand" "r,r,0")
> > > > > > + (sign_extend:DI (subreg:SI (match_dup 1) 0)))
> > > > > > + (eq (match_operand:DI 2 "register_operand" "r,r,r")
> > > > > > + (sign_extend:DI (subreg:SI (match_dup 2) 0))))
> > > > > > + (sign_extend:DI
> > > > > > + (any_div:SI (subreg:SI (match_dup 1) 0)
> > > > > > + (subreg:SI (match_dup 2) 0)))
> > > > > > + (unspec:DI [(const_int 0)] UNSPEC_BAD_DIVW)))]
> > > > >
> > > > > With this the compiler will still believe all bad {div,mod}.w{,u}
> > > >
> > > > I think this is already defined as UNSPEC. Isn’t the simpler the logic,
> > > > the
> > > > better?
> > >
> > > Yes, I think we should just use 4 different UNSPEC_ values and the simple
> > > version. But I've not find a way to use 4 different UNSPEC_ values in the
> > > RTL template except duplicating everything 4 times...
> >
> > I still have a question that I don't quite understand, that is, why that the
> > four generated strings are equivalent when using an UNSPEC name? My template
> > names are different, and they will not be automatically matched during
> > optimization.???
>
> Oh I get it, you mean
>
> (define_insn "<optab>di3_fake"
> [(set (match_operand:DI 0 "register_operand" "=r,&r,&r")
> (sign_extend:DI
> - (any_div:SI (match_operand:DI 1 "register_operand" "r,r,0")
> - (match_operand:DI 2 "register_operand" "r,r,r"))))]
> + (unspec:DI [(any_div:DI
> + (match_operand:DI 1 "register_operand" "r,r,0")
> + (match_operand:DI 2 "register_operand" "r,r,r"))]
> + UNSPEC_ANY_DIV)))]
> ""
> {
> return loongarch_output_division ("<insn>.w<u>\t%0,%1,%2", operands);
>
> Good idea! I think it's better than my stupid hacks :).
>
> I'd been thinking about:
>
> (define_insn "<optab>di3_fake"
> [(set (match_operand:DI 0 "register_operand" "=r,&r,&r")
> (sign_extend:DI
> - (any_div:SI (match_operand:DI 1 "register_operand" "r,r,0")
> - (match_operand:DI 2 "register_operand" "r,r,r"))))]
> + (unspec:DI [(match_operand:DI 1 "register_operand" "r,r,0")
> + (match_operand:DI 2 "register_operand" "r,r,r")]
> + UNSPEC_ANY_DIV)))]
> ""
> {
> return loongarch_output_division ("<insn>.w<u>\t%0,%1,%2", operands);
>
> and this is just wrong.
Is it better to modify it this way?
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -60,6 +60,7 @@ (define_c_enum "unspec" [
;; Stack tie
UNSPEC_TIE
+ UNSPEC_ANY_DIV
;; CRC
UNSPEC_CRC
UNSPEC_CRCC
@@ -900,7 +901,7 @@ (define_expand "<optab><mode>3"
(match_operand:GPR 2 "register_operand")))]
""
{
- if (GET_MODE (operands[0]) == SImode)
+ if (GET_MODE (operands[0]) == SImode && TARGET_64BIT)
{
rtx reg1 = gen_reg_rtx (DImode);
rtx reg2 = gen_reg_rtx (DImode);
@@ -938,9 +939,12 @@ (define_insn "*<optab><mode>3"
(define_insn "<optab>di3_fake"
[(set (match_operand:DI 0 "register_operand" "=r,&r,&r")
(sign_extend:DI
- (any_div:SI (match_operand:DI 1 "register_operand" "r,r,0")
- (match_operand:DI 2 "register_operand" "r,r,r"))))]
- ""
+ (unspec:SI
+ [(subreg:SI
+ (any_div:DI (match_operand:DI 1 "register_operand" "r,r,0")
+ (match_operand:DI 2 "register_operand" "r,r,r")) 0)]
+ UNSPEC_ANY_DIV)))]
+ "TARGET_64BIT"
{
return loongarch_output_division ("<insn>.w<u>\t%0,%1,%2", operands);
