| Message ID | mpt7dcisof6.fsf@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | fold: Optimise fold_view_convert_expr | expand |
On Sun, Dec 5, 2021 at 11:00 PM Richard Sandiford via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > When compiling an optabs.ii at -O2 with a release-checking build, > there were 210,172 calls to fold_view_convert_expr. 99.8% of them > were conversions of an INTEGER_CST to an ENUMERAL_TYPE, so this patch > adds a fast(er) path for that case. > > Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install? > > Richard > > > gcc/ > * fold-const.c (fold_view_convert_expr): Add a fast path for > conversions of INTEGER_CSTs to other integral types. > --- > gcc/fold-const.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/gcc/fold-const.c b/gcc/fold-const.c > index 0b9a42f764a..19613015ddb 100644 > --- a/gcc/fold-const.c > +++ b/gcc/fold-const.c > @@ -9128,6 +9128,13 @@ fold_view_convert_vector_encoding (tree type, tree expr) > static tree > fold_view_convert_expr (tree type, tree expr) > { > + /* Conversions of INTEGER_CSTs to ENUMERAL_TYPEs are very common, > + so handle them directly. */ > + if (INTEGRAL_TYPE_P (type) > + && TREE_CODE (expr) == INTEGER_CST > + && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))) > + return wide_int_to_tree (type, wi::to_wide (expr)); I suppose that TREE_CODE (expr) == INTEGER_CST && tree_nop_conversion_p (type, TREE_TYPE (expr)) might be more complete? In fact, it might be possible to do if (TREE_CODE (expr) == INTEGER_CST) { gcc_checking_assert (tree_nop_conversion_p (type, TREE_TYPE (expr)); return wide_int_to_tree (type, wi::to_wide (expr)); } or at least if (TREE_CODE (expr) == INTEGER_CST) { gcc_checking_assert (operand_equal_p (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))); return wide_int_to_tree (type, wi::zext (wi::to_widest (expr), TYPE_PRECISION (TREE_TYPE (expr))); } but I realize IL verification around VIEW_CONVERTs is incomplete and the above case likely mostly happens with match.pd unifying the vector/non-vector sign conversion path. That said, the intent was to not have VIEW_CONVERT between types with different precision since on GIMPLE/GENERIC the off-precision bits have no representation and thus cannot be "converted" as unchanging. Richard. > + > /* We support up to 512-bit values (for V8DFmode). */ > unsigned char buffer[64]; > int len; > -- > 2.31.1 >
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 0b9a42f764a..19613015ddb 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -9128,6 +9128,13 @@ fold_view_convert_vector_encoding (tree type, tree expr) static tree fold_view_convert_expr (tree type, tree expr) { + /* Conversions of INTEGER_CSTs to ENUMERAL_TYPEs are very common, + so handle them directly. */ + if (INTEGRAL_TYPE_P (type) + && TREE_CODE (expr) == INTEGER_CST + && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))) + return wide_int_to_tree (type, wi::to_wide (expr)); + /* We support up to 512-bit values (for V8DFmode). */ unsigned char buffer[64]; int len;