From adce30305f388ad174da58aa01412baa9c19764a Mon Sep 17 00:00:00 2001
From: Andrew Morris <voltrevo@gmail.com>
Date: Sun, 2 Jul 2023 09:55:38 +1000
Subject: [PATCH] jmpif true label -> jmp label

---
 valuescript_compiler/src/optimization/mod.rs  |  2 +-
 .../src/optimization/optimize.rs              |  4 +-
 ...remove_noops.rs => reduce_instructions.rs} | 41 +++++++++++++------
 3 files changed, 32 insertions(+), 15 deletions(-)
 rename valuescript_compiler/src/optimization/{remove_noops.rs => reduce_instructions.rs} (64%)

diff --git a/valuescript_compiler/src/optimization/mod.rs b/valuescript_compiler/src/optimization/mod.rs
index abd5266..67d7d38 100644
--- a/valuescript_compiler/src/optimization/mod.rs
+++ b/valuescript_compiler/src/optimization/mod.rs
@@ -2,8 +2,8 @@ mod collapse_pointers_of_pointers;
 mod extract_constants;
 mod kal;
 mod optimize;
+mod reduce_instructions;
 mod remove_meta_lines;
-mod remove_noops;
 mod shake_tree;
 mod simplify;
 pub mod try_to_kal;
diff --git a/valuescript_compiler/src/optimization/optimize.rs b/valuescript_compiler/src/optimization/optimize.rs
index 6aa75fa..1b954d5 100644
--- a/valuescript_compiler/src/optimization/optimize.rs
+++ b/valuescript_compiler/src/optimization/optimize.rs
@@ -3,8 +3,8 @@ use crate::name_allocator::NameAllocator;
 
 use super::collapse_pointers_of_pointers::collapse_pointers_of_pointers;
 use super::extract_constants::extract_constants;
+use super::reduce_instructions::reduce_instructions;
 use super::remove_meta_lines::remove_meta_lines;
-use super::remove_noops::remove_noops;
 use super::shake_tree::shake_tree;
 use super::simplify::simplify;
 
@@ -14,7 +14,7 @@ pub fn optimize(module: &mut Module, pointer_allocator: &mut NameAllocator) {
 
   for _ in 0..2 {
     simplify(module);
-    remove_noops(module);
+    reduce_instructions(module);
   }
 
   remove_meta_lines(module);
diff --git a/valuescript_compiler/src/optimization/remove_noops.rs b/valuescript_compiler/src/optimization/reduce_instructions.rs
similarity index 64%
rename from valuescript_compiler/src/optimization/remove_noops.rs
rename to valuescript_compiler/src/optimization/reduce_instructions.rs
index 97dac5a..9860b5e 100644
--- a/valuescript_compiler/src/optimization/remove_noops.rs
+++ b/valuescript_compiler/src/optimization/reduce_instructions.rs
@@ -5,29 +5,29 @@ use crate::{
   instruction::Instruction,
 };
 
-pub fn remove_noops(module: &mut Module) {
+pub fn reduce_instructions(module: &mut Module) {
   for defn in &mut module.definitions {
     if let DefinitionContent::Function(fn_) = &mut defn.content {
       for line in take(&mut fn_.body) {
-        if let FnLine::Instruction(instr) = &line {
-          if is_noop(instr) {
-            continue;
+        if let FnLine::Instruction(instr) = line {
+          if let Some(instr) = reduce(instr) {
+            fn_.body.push(FnLine::Instruction(instr));
           }
+        } else {
+          fn_.body.push(line);
         }
-
-        fn_.body.push(line);
       }
     }
   }
 }
 
-fn is_noop(instr: &Instruction) -> bool {
+fn reduce(instr: Instruction) -> Option<Instruction> {
   use Instruction::*;
 
-  match instr {
+  match &instr {
     End | OpInc(..) | OpDec(..) | Call(..) | Apply(..) | SubCall(..) | Jmp(..) | New(..)
     | Throw(..) | SetCatch(..) | UnsetCatch | ConstSubCall(..) | RequireMutableThis
-    | ThisSubCall(..) | Next(..) | Yield(..) | YieldStar(..) => false,
+    | ThisSubCall(..) | Next(..) | Yield(..) | YieldStar(..) => Some(instr),
 
     Mov(_, dst)
     | OpPlus(_, _, dst)
@@ -66,9 +66,26 @@ fn is_noop(instr: &Instruction) -> bool {
     | UnaryMinus(_, dst)
     | Import(_, dst)
     | ImportStar(_, dst)
-    | Cat(_, dst) => dst.is_ignore(),
+    | Cat(_, dst) => {
+      if dst.is_ignore() {
+        None
+      } else {
+        Some(instr)
+      }
+    }
 
-    JmpIf(cond, _) => *cond == Value::Bool(false),
-    UnpackIterRes(_, value_dst, done_dst) => value_dst.is_ignore() && done_dst.is_ignore(),
+    JmpIf(cond, label_ref) => match cond {
+      // TODO: Kal::from_value(cond).is_truthy()
+      Value::Bool(false) => None,
+      Value::Bool(true) => Some(Instruction::Jmp(label_ref.clone())),
+      _ => Some(instr),
+    },
+    UnpackIterRes(_, value_dst, done_dst) => {
+      if value_dst.is_ignore() && done_dst.is_ignore() {
+        None
+      } else {
+        Some(instr)
+      }
+    }
   }
 }