fix(ssa): Validate signed mul overflow (#8798)

Author: vezenovm

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

@@ -324,6 +324,8 @@ mod tests {
           b0(v0: u1, v1: i32):
             v2 = cast v0 as i32
             v3 = mul v2, v1
+            v4 = cast v3 as u64
+            v6 = truncate v4 to 32 bits, max_bit_size: 64
             return v2
         }
         ";

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

@@ -1093,7 +1093,7 @@ mod test {
             v9 = unchecked_add v2, i32 1
             jmp b1(v9)
           b6():
-            v10 = mul v0, v1
+            v10 = unchecked_mul v0, v1
             constrain v10 == i32 6
             v12 = unchecked_add v3, i32 1
             jmp b4(v12)
@@ -1110,7 +1110,7 @@ mod test {
         let expected = "
         brillig(inline) fn main f0 {
           b0(v0: i32, v1: i32):
-            v4 = mul v0, v1
+            v4 = unchecked_mul v0, v1
             constrain v4 == i32 6
             jmp b1(i32 0)
           b1(v2: i32):

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

@@ -1490,9 +1490,9 @@ mod tests {
             v11 = array_get v0, index v10 -> u64
             v12 = add v11, u64 1
             v13 = array_set v9, index v10, value v12
-            v15 = add v1, {idx_type} 1
+            v15 = unchecked_add v1, {idx_type} 1
             store v13 at v4
-            v16 = add v1, {idx_type} 1 // duplicate
+            v16 = unchecked_add v1, {idx_type} 1 // duplicate
             jmp b1(v16)
           b2():
             v8 = load v4 -> [u64; 6]

compiler/noirc_evaluator/src/ssa/parser/into_ssa.rs

@@ -16,7 +16,6 @@ use crate::ssa::{
         value::ValueId,
     },
     opt::pure::FunctionPurities,
-    validation::validate_function,
 };
 
 use super::{
@@ -558,10 +557,6 @@ impl Translator {
         // before each print.
         ssa.normalize_ids();
 
-        for function in ssa.functions.values() {
-            validate_function(function);
-        }
-
         ssa
     }