Box `thir::ExprKind::InlineAsm`.

This shrinks `thir::Expr`.

compiler/rustc_middle/src/thir.rs

@@ -133,6 +133,14 @@ pub struct ClosureExpr<'tcx> {
     pub fake_reads: Vec<(ExprId, FakeReadCause, hir::HirId)>,
 }
 
+#[derive(Clone, Debug, HashStable)]
+pub struct InlineAsmExpr<'tcx> {
+    pub template: &'tcx [InlineAsmTemplatePiece],
+    pub operands: Box<[InlineAsmOperand<'tcx>]>,
+    pub options: InlineAsmOptions,
+    pub line_spans: &'tcx [Span],
+}
+
 #[derive(Copy, Clone, Debug, HashStable)]
 pub enum BlockSafety {
     Safe,
@@ -432,12 +440,7 @@ pub enum ExprKind<'tcx> {
         def_id: DefId,
     },
     /// Inline assembly, i.e. `asm!()`.
-    InlineAsm {
-        template: &'tcx [InlineAsmTemplatePiece],
-        operands: Box<[InlineAsmOperand<'tcx>]>,
-        options: InlineAsmOptions,
-        line_spans: &'tcx [Span],
-    },
+    InlineAsm(Box<InlineAsmExpr<'tcx>>),
     /// An expression taking a reference to a thread local.
     ThreadLocalRef(DefId),
     /// A `yield` expression.
@@ -804,7 +807,7 @@ mod size_asserts {
     use super::*;
     // These are in alphabetical order, which is easy to maintain.
     static_assert_size!(Block, 56);
-    static_assert_size!(Expr<'_>, 80);
+    static_assert_size!(Expr<'_>, 64);
     static_assert_size!(Pat<'_>, 24);
     static_assert_size!(Stmt<'_>, 72);
 }

compiler/rustc_middle/src/thir/visit.rs

 use super::{
-    Arm, Block, ClosureExpr, Expr, ExprKind, Guard, InlineAsmOperand, Pat, PatKind, Stmt, StmtKind,
+    Arm, Block, ClosureExpr, Expr, ExprKind, Guard, InlineAsmExpr, InlineAsmOperand, Pat, PatKind, Stmt, StmtKind,
     Thir,
 };
 
@@ -140,7 +140,7 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
         NamedConst { def_id: _, substs: _, user_ty: _ } => {}
         ConstParam { param: _, def_id: _ } => {}
         StaticRef { alloc_id: _, ty: _, def_id: _ } => {}
-        InlineAsm { ref operands, template: _, options: _, line_spans: _ } => {
+        InlineAsm(box InlineAsmExpr { ref operands, template: _, options: _, line_spans: _ }) => {
             for op in &**operands {
                 use InlineAsmOperand::*;
                 match op {

compiler/rustc_mir_build/src/build/expr/into.rs

@@ -400,7 +400,7 @@ pub(crate) fn expr_into_dest(
                 );
                 block.unit()
             }
-            ExprKind::InlineAsm { template, ref operands, options, line_spans } => {
+            ExprKind::InlineAsm(box InlineAsmExpr { template, ref operands, options, line_spans }) => {
                 use rustc_middle::{mir, thir};
                 let operands = operands
                     .into_iter()

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -562,7 +562,7 @@ fn make_mirror_unadjusted(&mut self, expr: &'tcx hir::Expr<'tcx>) -> Expr<'tcx>
                 self.convert_path_expr(expr, res)
             }
 
-            hir::ExprKind::InlineAsm(ref asm) => ExprKind::InlineAsm {
+            hir::ExprKind::InlineAsm(ref asm) => ExprKind::InlineAsm(Box::new(InlineAsmExpr {
                 template: asm.template,
                 operands: asm
                     .operands
@@ -621,7 +621,7 @@ fn make_mirror_unadjusted(&mut self, expr: &'tcx hir::Expr<'tcx>) -> Expr<'tcx>
                     .collect(),
                 options: asm.options,
                 line_spans: asm.line_spans,
-            },
+            })),
 
             hir::ExprKind::ConstBlock(ref anon_const) => {
                 let ty = self.typeck_results().node_type(anon_const.hir_id);