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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/98365] Miss vectoization for signed char ifcvt
Date: Tue, 05 Jan 2021 05:09:19 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98365

--- Comment #1 from Hongtao.liu <crazylht at gmail dot com> ---

> Shouldn't cnt_21 =3D PHI <cnt_9(7), 0(15)>, stmt relevant?
>=20

for stmt: cnt.1_7 =3D (unsigned char) cnt_21, the operand is defined by a
previous iteration of the loop which is assumed to be handled in
induction/reduction.

But vect_analyze_scalar_cycles can't get reduction of cnt as (cnt_9 =3D _3 =
=3D=3D _6
? cnt_16 : cnt_21;_ since scalar evolution only handle
     - an SSA_NAME,
     - an INTEGER_CST,
     - a PLUS_EXPR,
     - a POINTER_PLUS_EXPR,
     - a MINUS_EXPR,
     - an ASSERT_EXPR,
     - other cases are not yet handled.  */=