On Mon, Jun 12, 2017 at 12:56 AM, Tamar Christina <tamar.christ...@arm.com> wrote: > Hi All, > > this patch implements a optimization rewriting > > x * copysign (1.0, y) and > x * copysign (-1.0, y)
This reminds me: copysign(-1.0, y) can be just optimized to: copysign(1.0, y) I did that in my patch here: https://gcc.gnu.org/ml/gcc-patches/2017-06/msg01860.html This should allow you to reduce the number of patterns needed to match here. Note I still think we could do this in expand without a new builtin/internal function. I might go and code that up soonish. Thanks, Andrew > > to: > > x ^ (y & (1 << sign_bit_position)) > > This is done by creating a special builtin during matching and generate the > appropriate instructions during expand. This new builtin is called XORSIGN. > > The expansion of xorsign depends on if the backend has an appropriate optab > available. If this is not the case then we use a modified version of the > existing > copysign which does not take the abs value of the first argument as a fall > back. > > This patch is a revival of a previous patch > https://gcc.gnu.org/ml/gcc-patches/2015-10/msg00069.html > > Bootstrapped on both aarch64-none-linux-gnu and x86_64 with no issues. > Regression done on aarch64-none-linux-gnu and no regressions. > > Ok for trunk? > > gcc/ > 2017-06-07 Tamar Christina <tamar.christ...@arm.com> > > * builtins.def (BUILT_IN_XORSIGN, BUILT_IN_XORSIGNF): New. > (BUILT_IN_XORSIGNL, BUILT_IN_XORSIGN_FLOAT_NX): Likewise. > * match.pd (mult (COPYSIGN:s real_onep @0) @1): New simplifier. > (mult (COPYSIGN:s real_mus_onep @0) @1): Likewise. > (copysigns @0 (negate @1)): Likewise. > * builtins.c (expand_builtin_copysign): Promoted local to argument. > (expand_builtin): Added CASE_FLT_FN_FLOATN_NX (BUILT_IN_XORSIGN) and > CASE_FLT_FN (BUILT_IN_XORSIGN). > (BUILT_IN_COPYSIGN): Updated function call. > * optabs.h (expand_copysign): New bool. > (expand_xorsign): New. > * optabs.def (xorsign_optab): New. > * optabs.c (expand_copysign): New parameter. > * fortran/f95-lang.c (xorsignl, xorsign, xorsignf): New. > * fortran/mathbuiltins.def (XORSIGN): New. > > gcc/testsuite/ > 2017-06-07 Tamar Christina <tamar.christ...@arm.com> > > * gcc.dg/tree-ssa/xorsign.c: New. > * gcc.dg/xorsign_exec.c: New. > * gcc.dg/vec-xorsign_exec.c: New. > * gcc.dg/tree-ssa/reassoc-39.c (f2, f3): Updated constant to 2.
