fix(ssa): Remove OOB checks inserted during DIE

compiler/noirc_evaluator/src/ssa/opt/preprocess_fns.rs

@@ -59,7 +59,7 @@ impl Ssa {
             // Try to reduce the number of blocks.
             function.simplify_function();
             // Remove leftover instructions.
-            function.dead_instruction_elimination(true, false, false);
+            function.dead_instruction_elimination(false, false);
 
             // Put it back into the SSA, so the next functions can pick it up.
             self.functions.insert(id, function);

compiler/noirc_evaluator/src/ssa/ssa_gen/context.rs

@@ -868,12 +868,34 @@ impl<'a> FunctionContext<'a> {
         match lvalue {
             LValue::Ident => unreachable!("Cannot assign to a variable without a reference"),
             LValue::Index { old_array: mut array, index, array_lvalue, location } => {
+                let array_type = &self.builder.type_of_value(array);
+
+                // Checks for index Out-of-bounds
+                match array_type {
+                    Type::Array(_, len) => {
+                        let len =
+                            self.builder.numeric_constant(*len as u128, NumericType::length_type());
+                        self.codegen_access_check(index, len);
+                    }
+                    _ => unreachable!("must have array or slice but got {array_type}"),
+                }
+
                 array = self.assign_lvalue_index(new_value, array, index, location);
                 self.assign_new_value(*array_lvalue, array.into());
             }
             LValue::SliceIndex { old_slice: slice, index, slice_lvalue, location } => {
                 let mut slice_values = slice.into_value_list(self);
 
+                let array_type = &self.builder.type_of_value(slice_values[1]);
+
+                // Checks for index Out-of-bounds
+                match array_type {
+                    Type::Slice(_) => {
+                        self.codegen_access_check(index, slice_values[0]);
+                    }
+                    _ => unreachable!("must have array or slice but got {array_type}"),
+                }
+
                 slice_values[1] =
                     self.assign_lvalue_index(new_value, slice_values[1], index, location);
 

test_programs/execution_success/array_oob_regression_7952/Nargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "array_oob_regression_7952"
+type = "bin"
+authors = [""]
+
+[dependencies]

test_programs/execution_success/array_oob_regression_7952/Prover.toml

@@ -0,0 +1,2 @@
+a = [[]]
+b = 1

test_programs/execution_success/array_oob_regression_7952/src/main.nr

@@ -0,0 +1,7 @@
+fn main(a: [[u32; 0]; 1], b: bool) -> pub [u32; 0] {
+    if (b) {
+        a[0]
+    } else {
+        a[0]
+    }
+}

test_programs/execution_success/array_oob_regression_7952/stdout.txt

@@ -0,0 +1 @@
+[array_oob_regression_7952] Circuit output: Vec([])

test_programs/execution_success/array_oob_regression_7965/Nargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "array_oob_regression_7965"
+type = "bin"
+authors = [""]
+
+[dependencies]

test_programs/execution_success/array_oob_regression_7965/Prover.toml

@@ -0,0 +1,2 @@
+a = 1
+b = [[0, 1, 0, "\\\t"], [0, 1, 1, "mp"], [0, 0, 0, "\t/"], [0, 0, 0, "ab"]]

test_programs/execution_success/array_oob_regression_7965/src/main.nr

@@ -0,0 +1,9 @@
+global G_A: [[bool; 0]; 2] = [[], []];
+
+fn main(a: bool, b: [(u1, bool, u1, str<2>); 4]) -> pub [bool; 0] {
+    if (a) {
+        G_A[((((b[0].0 as u8) + (b[0].0 as u8)) as u32) % 2)]
+    } else {
+        G_A[((((b[0].0 as u8) + (b[0].0 as u8)) as u32) % 2)]
+    }
+}

test_programs/execution_success/array_oob_regression_7965/stdout.txt

@@ -0,0 +1 @@
+[array_oob_regression_7965] Circuit output: Vec([])

test_programs/execution_success/array_oob_regression_7975/Nargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "array_oob_regression_7975"
+type = "bin"
+authors = [""]
+
+[dependencies]

test_programs/execution_success/array_oob_regression_7975/Prover.toml

@@ -0,0 +1 @@
+b = [[0]]

test_programs/execution_success/array_oob_regression_7975/src/main.nr

@@ -0,0 +1,7 @@
+fn main(b: [[i1; 1]; 1]) -> pub [[i1; 1]; 1] {
+    if (b[0][0] == b[0][0]) {
+        b
+    } else {
+        b
+    }
+}

test_programs/execution_success/array_oob_regression_7975/stdout.txt

@@ -0,0 +1 @@
+[array_oob_regression_7975] Circuit output: Vec([Vec([Field(0)])])