feat: Sync from noir

.noir-sync-commit

@@ -1 +1 @@
-68c32b4ffd9b069fe4b119327dbf4018c17ab9d4
+dace07849aa28795abb30b3f9d979ffc6b6487e6

noir/noir-repo/compiler/noirc_evaluator/src/ssa.rs

@@ -141,6 +141,23 @@ pub(crate) fn optimize_into_acir(
         ssa.to_brillig(options.enable_brillig_logging)
     });
 
+    let ssa_gen_span = span!(Level::TRACE, "ssa_generation");
+    let ssa_gen_span_guard = ssa_gen_span.enter();
+
+    let ssa = SsaBuilder {
+        ssa,
+        print_ssa_passes: options.enable_ssa_logging,
+        print_codegen_timings: options.print_codegen_timings,
+    }
+    .run_pass(
+        |ssa| ssa.fold_constants_with_brillig(&brillig),
+        "After Constant Folding with Brillig:",
+    )
+    .run_pass(Ssa::dead_instruction_elimination, "After Dead Instruction Elimination:")
+    .finish();
+
+    drop(ssa_gen_span_guard);
+
     let artifacts = time("SSA to ACIR", options.print_codegen_timings, || {
         ssa.into_acir(&brillig, options.expression_width)
     })?;

noir/noir-repo/compiler/noirc_evaluator/src/ssa/ir/instruction.rs

@@ -11,7 +11,7 @@ use fxhash::FxHasher64;
 use iter_extended::vecmap;
 use noirc_frontend::hir_def::types::Type as HirType;
 
-use crate::ssa::opt::flatten_cfg::value_merger::ValueMerger;
+use crate::ssa::{ir::function::RuntimeType, opt::flatten_cfg::value_merger::ValueMerger};
 
 use super::{
     basic_block::BasicBlockId,
@@ -478,8 +478,19 @@ impl Instruction {
             | ArraySet { .. }
             | MakeArray { .. } => true,
 
+            // Store instructions must be removed by DIE in acir code, any load
+            // instructions should already be unused by that point.
+            //
+            // Note that this check assumes that it is being performed after the flattening
+            // pass and after the last mem2reg pass. This is currently the case for the DIE
+            // pass where this check is done, but does mean that we cannot perform mem2reg
+            // after the DIE pass.
+            Store { .. } => {
+                matches!(function.runtime(), RuntimeType::Acir(_))
+                    && function.reachable_blocks().len() == 1
+            }
+
             Constrain(..)
-            | Store { .. }
             | EnableSideEffectsIf { .. }
             | IncrementRc { .. }
             | DecrementRc { .. }