This case is covered by Wilco's previous reply: https://gcc.gnu.org/ml/gcc-patches/2017-08/msg00575.html
-----Original Message----- From: Richard Kenner [mailto:[email protected]] Sent: Tuesday, August 8, 2017 5:13 AM To: Michael Collison <[email protected]> Cc: [email protected]; nd <[email protected]>; [email protected] Subject: RE: [PATCH] [Aarch64] Optimize subtract in shift counts > The pattern will only be matched if the value is positive. More > specifically if the constant value is 32 (SImode) or 64 (DImode). I don't mean the constant, but the value subtracted from it. If that's negative, then we have a shift count larger than the wordsize.
