Replace locals in debuginfo records during dest_prop

Author: dianqk

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -277,7 +277,6 @@ impl<'tcx> MutVisitor<'tcx> for Merger<'tcx> {
                 if self.merged_locals.contains(*local) =>
             {
                 statement.make_nop(true);
-                return;
             }
             _ => (),
         };

tests/mir-opt/debuginfo/dest_prop.remap_debuginfo_locals.DestinationPropagation.diff

@@ -9,11 +9,12 @@
       let mut _4: bool;
 
       bb0: {
-          // DBG: _3 = &_1;
+-         // DBG: _3 = &_1;
 -         StorageLive(_4);
 -         _4 = copy _1;
 -         _3 = copy _2;
 -         switchInt(copy _4) -> [1: bb1, otherwise: bb2];
++         // DBG: _2 = &_1;
 +         nop;
 +         nop;
 +         nop;

tests/mir-opt/debuginfo/dest_prop.rs

@@ -1,4 +1,3 @@
-// skip-filecheck
 //@ test-mir-pass: DestinationPropagation
 //@ compile-flags: -g -Zmir-enable-passes=+DeadStoreElimination-initial
 
@@ -10,6 +9,10 @@ use std::intrinsics::mir::*;
 // EMIT_MIR dest_prop.remap_debuginfo_locals.DestinationPropagation.diff
 #[custom_mir(dialect = "runtime", phase = "post-cleanup")]
 pub fn remap_debuginfo_locals(a: bool, b: &bool) -> &bool {
+    // CHECK-LABEL: fn remap_debuginfo_locals(
+    // CHECK: debug c => [[c:_.*]];
+    // CHECK: bb0:
+    // CHECK-NEXT: DBG: [[c]] = &_1;
     mir! {
         let _3: &bool;
         let _4: bool;

tests/crashes/147485-2.rs renamed to tests/ui/debuginfo/dest_prop_debuginfo-147485.rs

@@ -1,6 +1,8 @@
-//@ known-bug: #147485
+//@ build-pass
 //@ compile-flags: -g -O
 
+// Regression test for #147485.
+
 #![crate_type = "lib"]
 
 pub fn foo(a: bool, b: bool) -> bool {