Fix #1688

crates/noirc_evaluator/src/ssa_refactor/acir_gen/mod.rs

@@ -346,7 +346,7 @@ impl Context {
             Value::Intrinsic(..) => todo!(),
             Value::Function(..) => unreachable!("ICE: All functions should have been inlined"),
             Value::Instruction { .. } | Value::Param { .. } => {
-                unreachable!("ICE: Should have been in cache {value:?}")
+                unreachable!("ICE: Should have been in cache {value_id} {value:?}")
             }
         };
         self.ssa_values.insert(value_id, acir_value.clone());

crates/noirc_evaluator/src/ssa_refactor/ir.rs

@@ -3,6 +3,7 @@ pub(crate) mod cfg;
 pub(crate) mod dfg;
 pub(crate) mod dom;
 pub(crate) mod function;
+pub(crate) mod function_inserter;
 pub(crate) mod instruction;
 pub(crate) mod map;
 pub(crate) mod post_order;

crates/noirc_evaluator/src/ssa_refactor/ir/function_inserter.rs

@@ -0,0 +1,129 @@
+use std::collections::HashMap;
+
+use iter_extended::vecmap;
+
+use super::{
+    basic_block::BasicBlockId,
+    dfg::InsertInstructionResult,
+    function::Function,
+    instruction::{Instruction, InstructionId},
+    value::ValueId,
+};
+
+/// The FunctionInserter can be used to help modify existing Functions
+/// and map old values to new values after re-inserting optimized versions
+/// of old instructions.
+pub(crate) struct FunctionInserter<'f> {
+    pub(crate) function: &'f mut Function,
+
+    values: HashMap<ValueId, ValueId>,
+}
+
+impl<'f> FunctionInserter<'f> {
+    pub(crate) fn new(function: &'f mut Function) -> FunctionInserter<'f> {
+        Self { function, values: HashMap::new() }
+    }
+
+    /// Resolves a ValueId to its new, updated value.
+    /// If there is no updated value for this id, this returns the same
+    /// ValueId that was passed in.
+    pub(crate) fn resolve(&mut self, value: ValueId) -> ValueId {
+        match self.values.get(&value) {
+            Some(value) => *value,
+            None => match &self.function.dfg[self.function.dfg.resolve(value)] {
+                super::value::Value::Array { array, element_type } => {
+                    let array = array.clone();
+                    let element_type = element_type.clone();
+                    let new_array = array.iter().map(|id| self.resolve(*id)).collect();
+                    let new_id = self.function.dfg.make_array(new_array, element_type);
+                    self.values.insert(value, new_id);
+                    new_id
+                }
+                _ => value,
+            },
+        }
+    }
+
+    /// Insert a key, value pair if the key isn't already present in the map
+    pub(crate) fn try_map_value(&mut self, key: ValueId, value: ValueId) {
+        self.values.entry(key).or_insert(value);
+    }
+
+    /// Insert a key, value pair in the map
+    pub(crate) fn map_value(&mut self, key: ValueId, value: ValueId) {
+        self.values.insert(key, value);
+    }
+
+    pub(crate) fn map_instruction(&mut self, id: InstructionId) -> Instruction {
+        self.function.dfg[id].clone().map_values(|id| self.resolve(id))
+    }
+
+    pub(crate) fn push_instruction(&mut self, id: InstructionId, block: BasicBlockId) {
+        let instruction = self.map_instruction(id);
+        self.push_instruction_value(instruction, id, block);
+    }
+
+    pub(crate) fn push_instruction_value(
+        &mut self,
+        instruction: Instruction,
+        id: InstructionId,
+        block: BasicBlockId,
+    ) {
+        let results = self.function.dfg.instruction_results(id);
+        let results = vecmap(results, |id| self.function.dfg.resolve(*id));
+
+        let ctrl_typevars = instruction
+            .requires_ctrl_typevars()
+            .then(|| vecmap(&results, |result| self.function.dfg.type_of_value(*result)));
+
+        let new_results =
+            self.function.dfg.insert_instruction_and_results(instruction, block, ctrl_typevars);
+
+        Self::insert_new_instruction_results(&mut self.values, &results, new_results);
+    }
+
+    /// Modify the values HashMap to remember the mapping between an instruction result's previous
+    /// ValueId (from the source_function) and its new ValueId in the destination function.
+    pub(crate) fn insert_new_instruction_results(
+        values: &mut HashMap<ValueId, ValueId>,
+        old_results: &[ValueId],
+        new_results: InsertInstructionResult,
+    ) {
+        assert_eq!(old_results.len(), new_results.len());
+
+        match new_results {
+            InsertInstructionResult::SimplifiedTo(new_result) => {
+                values.insert(old_results[0], new_result);
+            }
+            InsertInstructionResult::Results(new_results) => {
+                for (old_result, new_result) in old_results.iter().zip(new_results) {
+                    values.insert(*old_result, *new_result);
+                }
+            }
+            InsertInstructionResult::InstructionRemoved => (),
+        }
+    }
+
+    pub(crate) fn remember_block_params(&mut self, block: BasicBlockId, new_values: &[ValueId]) {
+        let old_parameters = self.function.dfg.block_parameters(block);
+
+        for (param, new_param) in old_parameters.iter().zip(new_values) {
+            // Don't overwrite any existing entries to avoid overwriting the induction variable
+            self.values.entry(*param).or_insert(*new_param);
+        }
+    }
+
+    pub(crate) fn remember_block_params_from_block(
+        &mut self,
+        block: BasicBlockId,
+        new_block: BasicBlockId,
+    ) {
+        let old_parameters = self.function.dfg.block_parameters(block);
+        let new_parameters = self.function.dfg.block_parameters(new_block);
+
+        for (param, new_param) in old_parameters.iter().zip(new_parameters) {
+            // Don't overwrite any existing entries to avoid overwriting the induction variable
+            self.values.entry(*param).or_insert(*new_param);
+        }
+    }
+}