Use Cow instead of &[] for InlineAsm MIR

Fixes #72386

Author: Amanieu

src/librustc_codegen_ssa/mir/block.rs

@@ -1034,7 +1034,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bug!("borrowck false edges in codegen")
             }
 
-            mir::TerminatorKind::InlineAsm { template, ref operands, options, destination } => {
+            mir::TerminatorKind::InlineAsm { ref template, ref operands, options, destination } => {
                 self.codegen_asm_terminator(
                     helper,
                     bx,

src/librustc_middle/mir/mod.rs

@@ -1185,7 +1185,7 @@ pub enum TerminatorKind<'tcx> {
     /// inline assembly is allowed to diverge.
     InlineAsm {
         /// The template for the inline assembly, with placeholders.
-        template: &'tcx [InlineAsmTemplatePiece],
+        template: Cow<'tcx, [InlineAsmTemplatePiece]>,
 
         /// The operands for the inline assembly, as `Operand`s or `Place`s.
         operands: Vec<InlineAsmOperand<'tcx>>,

src/librustc_middle/mir/type_foldable.rs

@@ -78,9 +78,12 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
                 FalseEdges { real_target, imaginary_target }
             }
             FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
-            InlineAsm { template, ref operands, options, destination } => {
-                InlineAsm { template, operands: operands.fold_with(folder), options, destination }
-            }
+            InlineAsm { ref template, ref operands, options, destination } => InlineAsm {
+                template: template.clone(),
+                operands: operands.fold_with(folder),
+                options,
+                destination,
+            },
         };
         Terminator { source_info: self.source_info, kind }
     }

src/librustc_mir_build/build/expr/into.rs

@@ -365,7 +365,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     block,
                     source_info,
                     TerminatorKind::InlineAsm {
-                        template,
+                        template: template.into(),
                         operands,
                         options,
                         destination: if options.contains(InlineAsmOptions::NORETURN) {