Adds x64 packed negation for the new backend

cranelift/codegen/src/isa/x64/inst/args.rs

@@ -412,6 +412,7 @@ pub enum SseOpcode {
     Psubd,
     Psubq,
     Psubw,
+    Pxor,
     Rcpss,
     Roundss,
     Roundsd,
@@ -512,6 +513,7 @@ impl SseOpcode {
             | SseOpcode::Psubd
             | SseOpcode::Psubq
             | SseOpcode::Psubw
+            | SseOpcode::Pxor
             | SseOpcode::Sqrtpd
             | SseOpcode::Sqrtsd
             | SseOpcode::Subpd
@@ -607,6 +609,7 @@ impl fmt::Debug for SseOpcode {
             SseOpcode::Psubd => "psubd",
             SseOpcode::Psubq => "psubq",
             SseOpcode::Psubw => "psubw",
+            SseOpcode::Pxor => "pxor",
             SseOpcode::Rcpss => "rcpss",
             SseOpcode::Roundss => "roundss",
             SseOpcode::Roundsd => "roundsd",

cranelift/codegen/src/isa/x64/inst/emit.rs

@@ -1703,6 +1703,7 @@ pub(crate) fn emit(
                 SseOpcode::Psubd => (LegacyPrefixes::_66, 0x0FFA, 2),
                 SseOpcode::Psubq => (LegacyPrefixes::_66, 0x0FFB, 2),
                 SseOpcode::Psubw => (LegacyPrefixes::_66, 0x0FF9, 2),
+                SseOpcode::Pxor => (LegacyPrefixes::_66, 0x0FEF, 2),
                 SseOpcode::Subps => (LegacyPrefixes::None, 0x0F5C, 2),
                 SseOpcode::Subpd => (LegacyPrefixes::_66, 0x0F5C, 2),
                 SseOpcode::Subss => (LegacyPrefixes::_F3, 0x0F5C, 2),

cranelift/codegen/src/isa/x64/inst/emit_tests.rs

@@ -3083,6 +3083,12 @@ fn test_x64_emit() {
         "pmuludq %xmm8, %xmm9",
     ));
 
+    insns.push((
+        Inst::xmm_rm_r(SseOpcode::Pxor, RegMem::reg(xmm11), w_xmm2),
+        "66410FEFD3",
+        "pxor    %xmm11, %xmm2",
+    ));
+
     // XMM_Mov_R_M: float stores
     insns.push((
         Inst::xmm_mov_r_m(SseOpcode::Movss, xmm15, Amode::imm_reg(128, r12), None),

cranelift/codegen/src/isa/x64/inst/mod.rs

@@ -1101,7 +1101,9 @@ impl Inst {
 
             Self::XMM_RM_R { op, src, dst, .. } => {
                 src.to_reg() == Some(dst.to_reg())
-                    && (*op == SseOpcode::Xorps || *op == SseOpcode::Xorpd)
+                    && (*op == SseOpcode::Xorps
+                        || *op == SseOpcode::Xorpd
+                        || *op == SseOpcode::Pxor)
             }
 
             Self::XmmRmRImm { op, src, dst, imm } => {