On Sat, May 6, 2023 at 10:26 AM Roger Sayle <ro...@nextmovesoftware.com> wrote: > > > This patch proposes adding run-time library support for bit reversal, > by adding a __bitrevsi2 function to libgcc. Thoughts/opinions?
Are you going to add a builtin for these functions too? If so that is recorded as https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50481 . Thanks, Andrew > > I'm also tempted to add __popcount[qh]i2 and __parity[qh]i2 to libgcc, > to allow the RTL optimizers to perform narrowing operations, but I'm > curious to hear whether QImode and HImode support, though more efficient, > is frowned by the libgcc maintainers/philosophy. > > This patch has been tested on x86_64-pc-linux-gnu with make bootstrap > and make -k check, both with and without --target_board=unix{-m32} and > on nvptx-none, with no new regressions. Ok for mainline? > > > 2023-05-06 Roger Sayle <ro...@nextmovesoftware.com> > > gcc/ChangeLog > * doc/libgcc.texi (__bitrevqi2): Document bit reversal run-time > functions; __bitrevqi2, __bitrevhi2, __bitrevsi2 and __bitrevdi2. > > libgcc/ChangeLog > * Makfile.in (lib2funcs): Add __bitrev[qhsd]i2. > * libgcc-std.ver.in (GCC_14.0.0): Add __bitrev[qhsd]i2. > * libgcc2.c (__bitrevqi2): New function. > (__bitrevhi2): Likewise. > (__bitrevsi2): Likewise. > (__bitrevdi2): Likewise. > * libgcc2.h (__bitrevqi2): Prototype here. > (__bitrevhi2): Likewise. > (__bitrevsi2): Likewise. > (__bitrevdi2): Likewise. > > Thanks in advance, > Roger > -- >
