[SIMD][x86_64] Add encoding for PMADDWD (#2530)

* [SIMD][x86_64] Add encoding for PMADDWD

* also for "experimental_x64"

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

@@ -498,6 +498,7 @@ pub enum SseOpcode {
     Pinsrb,
     Pinsrw,
     Pinsrd,
+    Pmaddwd,
     Pmaxsb,
     Pmaxsw,
     Pmaxsd,
@@ -661,6 +662,7 @@ impl SseOpcode {
             | SseOpcode::Pcmpgtd
             | SseOpcode::Pextrw
             | SseOpcode::Pinsrw
+            | SseOpcode::Pmaddwd
             | SseOpcode::Pmaxsw
             | SseOpcode::Pmaxub
             | SseOpcode::Pminsw
@@ -842,6 +844,7 @@ impl fmt::Debug for SseOpcode {
             SseOpcode::Pinsrb => "pinsrb",
             SseOpcode::Pinsrw => "pinsrw",
             SseOpcode::Pinsrd => "pinsrd",
+            SseOpcode::Pmaddwd => "pmaddwd",
             SseOpcode::Pmaxsb => "pmaxsb",
             SseOpcode::Pmaxsw => "pmaxsw",
             SseOpcode::Pmaxsd => "pmaxsd",

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

@@ -1873,6 +1873,7 @@ pub(crate) fn emit(
                 SseOpcode::Pcmpgtw => (LegacyPrefixes::_66, 0x0F65, 2),
                 SseOpcode::Pcmpgtd => (LegacyPrefixes::_66, 0x0F66, 2),
                 SseOpcode::Pcmpgtq => (LegacyPrefixes::_66, 0x0F3837, 3),
+                SseOpcode::Pmaddwd => (LegacyPrefixes::_66, 0x0FF5, 2),
                 SseOpcode::Pmaxsb => (LegacyPrefixes::_66, 0x0F383C, 3),
                 SseOpcode::Pmaxsw => (LegacyPrefixes::_66, 0x0FEE, 2),
                 SseOpcode::Pmaxsd => (LegacyPrefixes::_66, 0x0F383D, 3),

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

@@ -3067,6 +3067,12 @@ fn test_x64_emit() {
         "pmuludq %xmm8, %xmm9",
     ));
 
+    insns.push((
+        Inst::xmm_rm_r(SseOpcode::Pmaddwd, RegMem::reg(xmm8), w_xmm1),
+        "66410FF5C8",
+        "pmaddwd %xmm8, %xmm1",
+    ));
+
     insns.push((
         Inst::xmm_rm_r(SseOpcode::Pmaxsb, RegMem::reg(xmm15), w_xmm6),
         "66410F383CF7",