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From: "luoxhu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/100866] PPC: Inefficient code for vec_revb(vector
 unsigned short) < P9
Date: Tue, 15 Jun 2021 09:22:59 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100866

luoxhu at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |luoxhu at gcc dot gnu.org

--- Comment #2 from luoxhu at gcc dot gnu.org ---
But it only works for V8HImode, no better code generation for other modes l=
ike
V4SI/V2DI/V1TI to do byte swap with only two instructions vspltish+vrlh?

  unsigned int swap1[16] =3D {15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0};
  unsigned int swap2[16] =3D {7,6,5,4,3,2,1,0,15,14,13,12,11,10,9,8};
  unsigned int swap4[16] =3D {3,2,1,0,7,6,5,4,11,10,9,8,15,14,13,12};
  unsigned int swap8[16] =3D {1,0,3,2,5,4,7,6,9,8,11,10,13,12,15,14};

For example V4SI, need swap short first,  then swap word, it seems not so
straight forward than vperm?=