https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751
--- Comment #32 from JuzheZhong <juzhe.zhong at rivai dot ai> ---
(In reply to Richard Biener from comment #31)
> On GIMPLE an "undefined" operand representation would be the default
> definition of an SSA name with the appropriate type. That's a somewhat
> "heavy" representation and it also doesn't fit the target hook return value
> nicely,
> but we could handle a NULL_TREE return value from the target hook in the
> way to create such SSA name.
Thanks Richi.
How does this special "SSA" represent in RTX or How could I recognize this is
a "undefine" value in "expand" stage ?
I wondering whether my approach (passing a scalar 0) to the ELSE value which is
easily recognized in RTL backend ("expand stage") is suitable ?
Since you could see there will be one more move instruction inside the loop
which hurt vector performance a lot, I want to find a quick way to fix it for
now.
