thread reset-reuse through

compiler/gen_llvm/src/llvm/build.rs

@@ -970,15 +970,25 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
             struct_from_fields(env, struct_type, field_vals.into_iter().enumerate()).into()
         }
 
-        Tag {
+        Reuse {
+            arguments,
+            tag_layout: union_layout,
+            tag_id,
+            ..
+        }
+        | Tag {
             arguments,
             tag_layout: union_layout,
             tag_id,
             ..
         } => build_tag(env, scope, union_layout, *tag_id, arguments),
 
-        Reset(_) => todo!(),
+        Reset(_) => {
-        Reuse { .. } => todo!(),
+            // 1. fetch refcount
+            // 2. if rc == 1, reset the value
+            // TODO
+            env.context.i64_type().const_zero().into()
+        }
 
         StructAtIndex {
             index, structure, ..

compiler/load/src/file.rs

@@ -2072,6 +2072,8 @@ fn update<'a>(
                     &mut state.procedures,
                 );
 
+                Proc::insert_refcount_operations(arena, &mut state.procedures);
+
                 // display the mono IR of the module, for debug purposes
                 if roc_mono::ir::PRETTY_PRINT_IR_SYMBOLS {
                     let procs_string = state
@@ -2085,8 +2087,6 @@ fn update<'a>(
                     println!("{}", result);
                 }
 
-                Proc::insert_refcount_operations(arena, &mut state.procedures);
-
                 // This is not safe with the new non-recursive RC updates that we do for tag unions
                 //
                 //                Proc::optimize_refcount_operations(

compiler/mono/src/alias_analysis.rs

@@ -832,7 +832,14 @@ fn expr_spec(
     match expr {
         Literal(literal) => literal_spec(builder, block, literal),
         Call(call) => call_spec(builder, env, block, layout, call),
-        Tag {
+        Reuse {
+            tag_layout,
+            tag_name: _,
+            tag_id,
+            arguments,
+            ..
+        }
+        | Tag {
             tag_layout,
             tag_name: _,
             tag_id,
@@ -914,8 +921,12 @@ fn expr_spec(
                 Err(()) => unreachable!("empty array does not have a list layout"),
             }
         }
-        Reuse { .. } => todo!("currently unused"),
+        Reset(symbol) => {
-        Reset(_) => todo!("currently unused"),
+            let type_id = layout_spec(builder, layout)?;
+            let value_id = env.symbols[symbol];
+
+            builder.add_unknown_with(block, &[value_id], type_id)
+        }
         RuntimeErrorFunction(_) => {
             let type_id = layout_spec(builder, layout)?;
 

compiler/mono/src/ir.rs

@@ -234,7 +234,8 @@ impl<'a> Proc<'a> {
         procs: &mut MutMap<(Symbol, ProcLayout<'a>), Proc<'a>>,
     ) {
         for (key, proc) in procs.iter_mut() {
-            let new_proc = crate::reset_reuse::insert_reset_reuse(arena, home, ident_ids, proc.clone());
+            let new_proc =
+                crate::reset_reuse::insert_reset_reuse(arena, home, ident_ids, proc.clone());
             *proc = new_proc;
         }
     }
@@ -1287,11 +1288,12 @@ impl<'a> Expr<'a> {
                 alloc
                     .text("Reuse ")
                     .append(symbol_to_doc(alloc, *symbol))
+                    .append(alloc.space())
                     .append(doc_tag)
                     .append(alloc.space())
                     .append(alloc.intersperse(it, " "))
             }
-            Reset(symbol) => alloc.text("Reuse ").append(symbol_to_doc(alloc, *symbol)),
+            Reset(symbol) => alloc.text("Reset ").append(symbol_to_doc(alloc, *symbol)),
 
             Struct(args) => {
                 let it = args.iter().map(|s| symbol_to_doc(alloc, *s));

compiler/mono/src/reset_reuse.rs

@@ -1,5 +1,5 @@
 use crate::inc_dec::{collect_stmt, occurring_variables_expr, JPLiveVarMap, LiveVarSet};
-use crate::ir::{Call, Expr, Proc, Stmt, BranchInfo};
+use crate::ir::{BranchInfo, Call, Expr, Proc, Stmt};
 use crate::layout::{Layout, UnionLayout};
 use bumpalo::collections::Vec;
 use bumpalo::Bump;
@@ -25,15 +25,16 @@ pub fn insert_reset_reuse<'a, 'i>(
     proc
 }
 
+#[derive(Debug)]
 struct CtorInfo<'a> {
     id: u8,
     layout: UnionLayout<'a>,
 }
 
 fn may_reuse(tag_layout: UnionLayout, tag_id: u8, other: &CtorInfo) -> bool {
-    if tag_layout != other.layout {
+    //    if tag_layout != other.layout {
-        return false;
+    //        return false;
-    }
+    //    }
 
     // if the tag id is represented as NULL, there is no memory to re-use
     match tag_layout {
@@ -248,7 +249,8 @@ fn function_d_main<'a, 'i>(
     let arena = env.arena;
 
     match stmt {
-        Let(symbol, expr, layout, continuation) => match expr {
+        Let(symbol, expr, layout, continuation) => {
+            match expr {
                 Expr::Tag { arguments, .. } if arguments.iter().any(|s| *s == x) => {
                     // If the scrutinee `x` (the one that is providing memory) is being
                     // stored in a constructor, then reuse will probably not be able to reuse memory at runtime.
@@ -273,7 +275,8 @@ fn function_d_main<'a, 'i>(
                         (arena.alloc(let_stmt), found)
                     }
                 }
-        },
+            }
+        }
         Invoke {
             symbol,
             call,
@@ -409,17 +412,19 @@ fn function_r<'a, 'i>(env: &mut Env<'a, 'i>, stmt: &'a Stmt<'a>) -> &'a Stmt<'a>
 
                 let new_body = match info {
                     BranchInfo::None => temp,
-                    BranchInfo::Constructor { scrutinee, layout, tag_id } => {
+                    BranchInfo::Constructor {
-                        match layout {
+                        scrutinee,
+                        layout,
+                        tag_id,
+                    } => match layout {
                         Layout::Union(union_layout) => {
                             let ctor_info = CtorInfo {
                                 layout: *union_layout,
                                 id: *tag_id,
                             };
                             function_d(env, *scrutinee, &ctor_info, temp)
-                            },
-                            _ => temp,
                         }
+                        _ => temp,
                     },
                 };
 
@@ -432,17 +437,19 @@ fn function_r<'a, 'i>(env: &mut Env<'a, 'i>, stmt: &'a Stmt<'a>) -> &'a Stmt<'a>
 
                 let new_body = match info {
                     BranchInfo::None => temp,
-                    BranchInfo::Constructor { scrutinee, layout, tag_id } => {
+                    BranchInfo::Constructor {
-                        match layout {
+                        scrutinee,
+                        layout,
+                        tag_id,
+                    } => match layout {
                         Layout::Union(union_layout) => {
                             let ctor_info = CtorInfo {
                                 layout: *union_layout,
                                 id: *tag_id,
                             };
                             function_d(env, *scrutinee, &ctor_info, temp)
-                            },
-                            _ => temp,
                         }
+                        _ => temp,
                     },
                 };