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From: "chenglulu at loongson dot cn" <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 11:22:19 +0000
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X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: missed-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108357

--- Comment #19 from chenglulu <chenglulu at loongson dot cn> ---
(In reply to Xi Ruoyao from comment #18)
> (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 no=
t?
> > That will cause those conversions to be missed.
>=20
> Looks like we should define it, as our psABI says:
>=20
> In most cases, the unsigned integer data types are zero-extended when sto=
red
> in general-purpose register, and the signed integer data types are
> sign-extended. 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-bit values.
>=20
> IIUC it matches the semantics of TARGET_PROMOTE_PROTOTYPE

I also think this should be considered=