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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108357] [13 Regression] Dead Code Elimination
 Regression at -O2 since r13-4607-g2dc5d6b1e7ec88
Date: Fri, 14 Apr 2023 10:28:55 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108357

--- Comment #18 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #17)
> Isn't this the same issue as seen in another bug, most targets defining
> TARGET_PROMOTE_PROTOTYPES to hook_bool_const_tree_true but loongarch not?
> That will cause those conversions to be missed.

Looks like we should define it, as our psABI says:

In most cases, the unsigned integer data types are zero-extended when store=
d in
general-purpose register, and the signed integer data types are sign-extend=
ed.
However, in the LP64D ABI, unsigned 32-bit types, such as unsigned int, are
stored in general-purpose registers as proper sign extensions of their 32-b=
it
values.

IIUC it matches the semantics of TARGET_PROMOTE_PROTOTYPES.=