Eliminate intentional conversion from Smi to Int32 in HMul

src/hydrogen-infer-representation.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 64 matching lines @@
 
   // Set truncation flags for groups of connected phis. This is a conservative
   // approximation; the flag will be properly re-computed after representations
   // have been determined.
   if (phi_count > 0) {
     BitVector done(phi_count, zone());
     for (int i = 0; i < phi_count; ++i) {
       if (done.Contains(i)) continue;
 
       // Check if all uses of all connected phis in this group are truncating.
-      bool all_uses_everywhere_truncating = true;
+      bool all_uses_everywhere_truncating_int32 = true;
+      bool all_uses_everywhere_truncating_smi = true;
       for (BitVector::Iterator it(connected_phis[i]);
            !it.Done();
            it.Advance()) {
         int index = it.Current();
-        all_uses_everywhere_truncating &=
+        all_uses_everywhere_truncating_int32 &=
             phi_list->at(index)->CheckFlag(HInstruction::kTruncatingToInt32);
+        all_uses_everywhere_truncating_smi &=
+            phi_list->at(index)->CheckFlag(HInstruction::kTruncatingToSmi);
         done.Add(index);
       }
-      if (all_uses_everywhere_truncating) {
-        continue;  // Great, nothing to do.
+
+      if (!all_uses_everywhere_truncating_int32) {
+        // Clear truncation flag of this group of connected phis.
+        for (BitVector::Iterator it(connected_phis[i]);
+             !it.Done();
+             it.Advance()) {
+          int index = it.Current();
+          phi_list->at(index)->ClearFlag(HInstruction::kTruncatingToInt32);
+        }
       }
-      // Clear truncation flag of this group of connected phis.
-      for (BitVector::Iterator it(connected_phis[i]);
-           !it.Done();
-           it.Advance()) {
-        int index = it.Current();
-        phi_list->at(index)->ClearFlag(HInstruction::kTruncatingToInt32);
+      if (!all_uses_everywhere_truncating_smi) {
+        // Clear truncation flag of this group of connected phis.
+        for (BitVector::Iterator it(connected_phis[i]);
+             !it.Done();
+             it.Advance()) {
+          int index = it.Current();
+          phi_list->at(index)->ClearFlag(HInstruction::kTruncatingToSmi);
+        }
       }
     }
   }
 
   // Simplify constant phi inputs where possible.
   // This step uses kTruncatingToInt32 flags of phis.
   for (int i = 0; i < phi_count; ++i) {
     phi_list->at(i)->SimplifyConstantInputs();
   }
 
@@ skipping 50 matching lines @@
           current->ChangeRepresentation(Representation::Double());
         } else {
           current->ChangeRepresentation(Representation::Tagged());
         }
       }
     }
   }
 }
 
 } }  // namespace v8::internal