Replace `ExpressionOperandId` with enum `Operand`

Because the three kinds of operand are now distinguished explicitly, we no
longer need fiddly code to disambiguate counter IDs and expression IDs based on
the total number of counters/expressions in a function.

This does increase the size of operands from 4 bytes to 8 bytes, but that
shouldn't be a big deal since they are mostly stored inside boxed structures,
and the current coverage code is not particularly size-optimized anyway.

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 60cbb3d3d9d..d6a32497f7f 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -17,7 +17,7 @@ use rustc_hir::def_id::DefId;
 use rustc_llvm::RustString;
 use rustc_middle::bug;
 use rustc_middle::mir::coverage::{
-    CodeRegion, CounterValueReference, CoverageKind, ExpressionOperandId, InjectedExpressionId, Op,
+    CodeRegion, CounterValueReference, CoverageKind, InjectedExpressionId, Op, Operand,
 };
 use rustc_middle::mir::Coverage;
 use rustc_middle::ty;
@@ -203,9 +203,9 @@ impl<'tcx> Builder<'_, '_, 'tcx> {
         &mut self,
         instance: Instance<'tcx>,
         id: InjectedExpressionId,
-        lhs: ExpressionOperandId,
+        lhs: Operand,
         op: Op,
-        rhs: ExpressionOperandId,
+        rhs: Operand,
         region: Option<CodeRegion>,
     ) -> bool {
         if let Some(coverage_context) = self.coverage_context() {