[x64] Zero/sign-extend loads to 64-bit registers.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index f8cad769d3f00080aa136cfd6766095fd454cc2b..970f85d8d3dcc40cf63327d64c30ce0b816bb151 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -1754,6 +1754,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       ASSEMBLE_MOVX(movzxbl);
       __ AssertZeroExtended(i.OutputRegister());
       break;
+    case kX64Movsxbq:
+      ASSEMBLE_MOVX(movsxbq);
+      break;
+    case kX64Movzxbq:
+      ASSEMBLE_MOVX(movzxbq);
+      __ AssertZeroExtended(i.OutputRegister());
+      break;
     case kX64Movb: {
       size_t index = 0;
       Operand operand = i.MemoryOperand(&index);
@@ -1772,6 +1779,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       ASSEMBLE_MOVX(movzxwl);
       __ AssertZeroExtended(i.OutputRegister());
       break;
+    case kX64Movsxwq:
+      ASSEMBLE_MOVX(movsxwq);
+      break;
+    case kX64Movzxwq:
+      ASSEMBLE_MOVX(movzxwq);
+      __ AssertZeroExtended(i.OutputRegister());
+      break;
     case kX64Movw: {
       size_t index = 0;
       Operand operand = i.MemoryOperand(&index);