Fix regression from #850 (#851)

* fix regression from #850 - it is not always safe to fold added offsets into load/store offsets, as the add wraps but offset does not

* small refactoring to simplify asm2wasm pass invocation

1 files changed, 1 insertions, 27 deletions

diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 37207ffc7..04216f1ee 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -436,33 +436,7 @@ private:
 
   // fold constant factors into the offset
   void optimizeMemoryAccess(Expression*& ptr, Address& offset) {
-    while (1) {
-      auto* add = ptr->dynCast<Binary>();
-      if (!add) break;
-      if (add->op != AddInt32) break;
-      auto* left = add->left->dynCast<Const>();
-      auto* right = add->right->dynCast<Const>();
-      // note: in optimized code, we shouldn't see an add of two constants, so don't worry about that much
-      // (precompute would optimize that)
-      if (left) {
-        auto value = left->value.geti32();
-        if (value >= 0) {
-          offset = offset + value;
-          ptr = add->right;
-          continue;
-        }
-      }
-      if (right) {
-        auto value = right->value.geti32();
-        if (value >= 0) {
-          offset = offset + value;
-          ptr = add->left;
-          continue;
-        }
-      }
-      break;
-    }
-    // finally, ptr may be a const, but it isn't worth folding that in (we still have a const); in fact,
+    // ptr may be a const, but it isn't worth folding that in (we still have a const); in fact,
     // it's better to do the opposite for gzip purposes as well as for readability.
     auto* last = ptr->dynCast<Const>();
     if (last) {