[turbofan] Extend LoadElimination to introduce TypeGuards.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index ef341b39e238cc166e4ac71d075f46974447e3be..463bf030cd77b920840abfcde5107e0178e6d8b8 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -878,11 +878,13 @@ class RepresentationSelector {
       bool is_word64 = GetInfo(node->InputAt(0))->representation() ==
                        MachineRepresentation::kWord64;
 #ifdef DEBUG
-      // Check that all the inputs agree on being Word64.
-      DCHECK_EQ(IrOpcode::kPhi, node->opcode());  // This only works for phis.
-      for (int i = 1; i < node->op()->ValueInputCount(); i++) {
-        DCHECK_EQ(is_word64, GetInfo(node->InputAt(i))->representation() ==
-                                 MachineRepresentation::kWord64);
+      if (node->opcode() != IrOpcode::kTypeGuard) {
+        // Check that all the inputs agree on being Word64.
+        DCHECK_EQ(IrOpcode::kPhi, node->opcode());  // This only works for phis.
+        for (int i = 1; i < node->op()->ValueInputCount(); i++) {
+          DCHECK_EQ(is_word64, GetInfo(node->InputAt(i))->representation() ==
+                                   MachineRepresentation::kWord64);
+        }
       }
 #endif
       return is_word64 ? MachineRepresentation::kWord64