diff options
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/mod.rs | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs index d07a618f815..a13748a2d47 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs @@ -15,7 +15,9 @@ use rustc_hir::def::{CtorOf, DefKind, Res}; use rustc_hir::pat_util::EnumerateAndAdjustIterator; use rustc_hir::RangeEnd; use rustc_index::vec::Idx; -use rustc_middle::mir::interpret::{ErrorHandled, LitToConstError, LitToConstInput}; +use rustc_middle::mir::interpret::{ + ConstValue, ErrorHandled, LitToConstError, LitToConstInput, Scalar, +}; use rustc_middle::mir::{self, UserTypeProjection}; use rustc_middle::mir::{BorrowKind, Field, Mutability}; use rustc_middle::thir::{Ascription, BindingMode, FieldPat, LocalVarId, Pat, PatKind, PatRange}; @@ -755,11 +757,24 @@ pub(crate) fn compare_const_vals<'tcx>( ) -> Option<Ordering> { assert_eq!(a.ty(), b.ty()); - if a == b { - return Some(Ordering::Equal); + let ty = a.ty(); + + // This code is hot when compiling matches with many ranges. So we + // special-case extraction of evaluated scalars for speed, for types where + // raw data comparisons are appropriate. E.g. `unicode-normalization` has + // many ranges such as '\u{037A}'..='\u{037F}', and chars can be compared + // in this way. + match ty.kind() { + ty::Float(_) | ty::Int(_) => {} // require special handling, see below + _ => match (a, b) { + ( + mir::ConstantKind::Val(ConstValue::Scalar(Scalar::Int(a)), _a_ty), + mir::ConstantKind::Val(ConstValue::Scalar(Scalar::Int(b)), _b_ty), + ) => return Some(a.cmp(&b)), + _ => {} + }, } - let ty = a.ty(); let a = a.eval_bits(tcx, param_env, ty); let b = b.eval_bits(tcx, param_env, ty); |