diff --git a/src/engine/x86-64/X86_64SinglePassCompiler.v3 b/src/engine/x86-64/X86_64SinglePassCompiler.v3
index 936cd79a..a7bc9857 100644
--- a/src/engine/x86-64/X86_64SinglePassCompiler.v3
+++ b/src/engine/x86-64/X86_64SinglePassCompiler.v3
@@ -521,6 +521,10 @@ class X86_64SinglePassCompiler extends SinglePassCompiler {
 	def visit_I16X8_Q15MULRSAT_S() { do_op2_x_x_xtmp(ValueKind.V128, mmasm.emit_i16x8_q15mulrsat_s); }
 	def visit_I16X8_NARROW_I32X4_S() { do_op2_x_x(ValueKind.V128, asm.packssdw_s_s); }
 	def visit_I16X8_NARROW_I32X4_U() { do_op2_x_x(ValueKind.V128, asm.packusdw_s_s); }
+	def visit_I16X8_EXTEND_LOW_I8X16_S() { do_op1_x_x(ValueKind.V128, asm.pmovsxbw_s_s); }
+	def visit_I16X8_EXTEND_LOW_I8X16_U() { do_op1_x_x(ValueKind.V128, asm.pmovzxbw_s_s); }
+	def visit_I16X8_EXTEND_HIGH_I8X16_S() { do_op1_x(ValueKind.V128, mmasm.emit_i16x8_s_convert_i8x16_high); }
+	def visit_I16X8_EXTEND_HIGH_I8X16_U() { do_op1_x_xtmp(ValueKind.V128, mmasm.emit_i16x8_u_convert_i8x16_high); }	
 
 	def visit_I32X4_ADD() { do_op2_x_x(ValueKind.V128, asm.paddd_s_s); }
 	def visit_I32X4_SUB() { do_op2_x_x(ValueKind.V128, asm.psubd_s_s); }
@@ -552,6 +556,10 @@ class X86_64SinglePassCompiler extends SinglePassCompiler {
 	def visit_I32X4_TRUNC_SAT_F32X4_U() { do_op1_x_xtmp(ValueKind.V128, mmasm.emit_i32x4_trunc_sat_f32x4_u(_, _, X(allocTmp(ValueKind.V128)))); }
 	def visit_I32X4_TRUNC_SAT_F64X2_S_ZERO() { do_op1_x_gtmp_xtmp(ValueKind.V128, mmasm.emit_i32x4_trunc_sat_f64x2_s_zero(_, _, _, X(allocTmp(ValueKind.V128)))); }
 	def visit_I32X4_TRUNC_SAT_F64X2_U_ZERO() { do_op1_x_gtmp_xtmp(ValueKind.V128, mmasm.emit_i32x4_trunc_sat_f64x2_u_zero(_, _, _, X(allocTmp(ValueKind.V128)))); }
+	def visit_I32X4_EXTEND_LOW_I16X8_S() { do_op1_x_x(ValueKind.V128, asm.pmovsxwd_s_s); }
+	def visit_I32X4_EXTEND_LOW_I16X8_U() { do_op1_x_x(ValueKind.V128, asm.pmovzxwd_s_s); }
+	def visit_I32X4_EXTEND_HIGH_I16X8_S() { do_op1_x(ValueKind.V128, mmasm.emit_i32x4_s_convert_i16x8_high); }
+	def visit_I32X4_EXTEND_HIGH_I16X8_U() { do_op1_x_xtmp(ValueKind.V128, mmasm.emit_i32x4_u_convert_i16x8_high); }
 
 	def visit_I64X2_ADD() { do_op2_x_x(ValueKind.V128, asm.paddq_s_s); }
 	def visit_I64X2_SUB() { do_op2_x_x(ValueKind.V128, asm.psubq_s_s); }
@@ -564,6 +572,10 @@ class X86_64SinglePassCompiler extends SinglePassCompiler {
 	def visit_I64X2_GE_S() { do_op2_x_x_xtmp(ValueKind.V128, mmasm.emit_i64x2_ge_s); }
 	def visit_I64X2_LE_S() { do_c_op2_x_x_xtmp(ValueKind.V128, mmasm.emit_i64x2_ge_s); }
 	def visit_I64X2_ABS() { do_op1_x_xtmp(ValueKind.V128, mmasm.emit_i64x2_abs); }
+	def visit_I64X2_EXTEND_LOW_I32X4_S() { do_op1_x_x(ValueKind.V128, asm.pmovsxdq_s_s); }
+	def visit_I64X2_EXTEND_LOW_I32X4_U() { do_op1_x_x(ValueKind.V128, asm.pmovzxdq_s_s); }
+	def visit_I64X2_EXTEND_HIGH_I32X4_S() { do_op1_x(ValueKind.V128, mmasm.emit_i64x2_s_convert_i32x4_high); }
+	def visit_I64X2_EXTEND_HIGH_I32X4_U() { do_op1_x_xtmp(ValueKind.V128, mmasm.emit_i64x2_u_convert_i32x4_high); }
 
 	def visit_F32X4_ADD() { do_op2_x_x(ValueKind.V128, asm.addps_s_s); }
 	def visit_F32X4_SUB() { do_op2_x_x(ValueKind.V128, asm.subps_s_s); }