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Improve derived discriminant testing.

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Currently the generated code for methods like `eq`, `ne`, and `partial_cmp`
includes stuff like this:
```
let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi {
    ...
}
```
This commit removes the unnecessary `true &&`, and makes the generating
code a little easier to read in the process. It also fixes some errors
in comments.
This commit is contained in:
Nicholas Nethercote 2022-06-22 15:00:53 +10:00
parent ea74997c41
commit 00207ead61
2 changed files with 27 additions and 32 deletions
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33
compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
View File

@ -1392,37 +1392,32 @@ impl<'a> MethodDef<'a> {
// //
// i.e., for `enum E<T> { A, B(1), C(T, T) }`, and a deriving // i.e., for `enum E<T> { A, B(1), C(T, T) }`, and a deriving
// with three Self args, builds three statements: // with three Self args, builds three statements:
//
// ``` // ```
// let __self0_vi = std::intrinsics::discriminant_value(&self); // let __self_vi = std::intrinsics::discriminant_value(&self);
// let __self1_vi = std::intrinsics::discriminant_value(&arg1); // let __arg_1_vi = std::intrinsics::discriminant_value(&arg1);
// let __self2_vi = std::intrinsics::discriminant_value(&arg2); // let __arg_2_vi = std::intrinsics::discriminant_value(&arg2);
// ``` // ```
let mut index_let_stmts: Vec<ast::Stmt> = Vec::with_capacity(vi_idents.len() + 1); let mut index_let_stmts: Vec<ast::Stmt> = Vec::with_capacity(vi_idents.len() + 1);
// We also build an expression which checks whether all discriminants are equal // We also build an expression which checks whether all discriminants are equal:
// discriminant_test = __self0_vi == __self1_vi && __self0_vi == __self2_vi && ... // `__self_vi == __arg_1_vi && __self_vi == __arg_2_vi && ...`
let mut discriminant_test = cx.expr_bool(span, true); let mut discriminant_test = cx.expr_bool(span, true);
for (i, (&ident, self_arg)) in iter::zip(&vi_idents, &self_args).enumerate() {
let mut first_ident = None;
for (&ident, self_arg) in iter::zip(&vi_idents, &self_args) {
let self_addr = cx.expr_addr_of(span, self_arg.clone()); let self_addr = cx.expr_addr_of(span, self_arg.clone());
let variant_value = let variant_value =
deriving::call_intrinsic(cx, span, sym::discriminant_value, vec![self_addr]); deriving::call_intrinsic(cx, span, sym::discriminant_value, vec![self_addr]);
let let_stmt = cx.stmt_let(span, false, ident, variant_value); let let_stmt = cx.stmt_let(span, false, ident, variant_value);
index_let_stmts.push(let_stmt); index_let_stmts.push(let_stmt);
match first_ident { if i > 0 {
Some(first) => { let id0 = cx.expr_ident(span, vi_idents[0]);
let first_expr = cx.expr_ident(span, first);
let id = cx.expr_ident(span, ident); let id = cx.expr_ident(span, ident);
let test = cx.expr_binary(span, BinOpKind::Eq, first_expr, id); let test = cx.expr_binary(span, BinOpKind::Eq, id0, id);
discriminant_test = discriminant_test = if i == 1 {
test
} else {
cx.expr_binary(span, BinOpKind::And, discriminant_test, test) cx.expr_binary(span, BinOpKind::And, discriminant_test, test)
} };
None => {
first_ident = Some(ident);
}
} }
} }
@ -1453,7 +1448,7 @@ impl<'a> MethodDef<'a> {
// } // }
// } // }
// else { // else {
// <delegated expression referring to __self0_vi, et al.> // <delegated expression referring to __self_vi, et al.>
// } // }
let all_match = cx.expr_match(span, match_arg, match_arms); let all_match = cx.expr_match(span, match_arg, match_arms);
let arm_expr = cx.expr_if(span, discriminant_test, all_match, Some(arm_expr)); let arm_expr = cx.expr_if(span, discriminant_test, all_match, Some(arm_expr));

22
src/test/ui/deriving/deriving-all-codegen.stdout
View File

@ -648,7 +648,7 @@ impl ::core::cmp::PartialEq for Fieldless {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { _ => true, } match (&*self, &*other) { _ => true, }
} else { false } } else { false }
} }
@ -672,7 +672,7 @@ impl ::core::cmp::PartialOrd for Fieldless {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
_ => _ =>
::core::option::Option::Some(::core::cmp::Ordering::Equal), ::core::option::Option::Some(::core::cmp::Ordering::Equal),
@ -692,7 +692,7 @@ impl ::core::cmp::Ord for Fieldless {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
_ => ::core::cmp::Ordering::Equal, _ => ::core::cmp::Ordering::Equal,
} }
@ -783,7 +783,7 @@ impl ::core::cmp::PartialEq for Mixed {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) => (&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
(*__self_0) == (*__arg_1_0), (*__self_0) == (*__arg_1_0),
@ -800,7 +800,7 @@ impl ::core::cmp::PartialEq for Mixed {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) => (&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
(*__self_0) != (*__arg_1_0), (*__self_0) != (*__arg_1_0),
@ -837,7 +837,7 @@ impl ::core::cmp::PartialOrd for Mixed {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) => (&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0), match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0),
@ -880,7 +880,7 @@ impl ::core::cmp::Ord for Mixed {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) => (&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) { match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) {
@ -973,7 +973,7 @@ impl ::core::cmp::PartialEq for Fielded {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) => (&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
(*__self_0) == (*__arg_1_0), (*__self_0) == (*__arg_1_0),
@ -991,7 +991,7 @@ impl ::core::cmp::PartialEq for Fielded {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) => (&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
(*__self_0) != (*__arg_1_0), (*__self_0) != (*__arg_1_0),
@ -1029,7 +1029,7 @@ impl ::core::cmp::PartialOrd for Fielded {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) => (&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0), match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0),
@ -1072,7 +1072,7 @@ impl ::core::cmp::Ord for Fielded {
{ {
let __self_vi = ::core::intrinsics::discriminant_value(&*self); let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other); let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi { if __self_vi == __arg_1_vi {
match (&*self, &*other) { match (&*self, &*other) {
(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) => (&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) { match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) {