x64: Add a smattering of lowerings for shuffle specializations (#5930)

* x64: Add lowerings for `punpck{h,l}wd`

Add some special cases for `shuffle` for more specialized x86
instructions.

* x64: Add `shuffle` lowerings for `pshufd`

This commit adds special-cased lowerings for the x64 `shuffle`
instruction when the `pshufd` instruction alone is necessary. This is
possible when the shuffle immediate permutes 32-bit values within one of
the vector inputs of the `shuffle` instruction, but not both.

* x64: Add shuffle lowerings for `punpck{h,l}{q,}dq`

This adds specific permutations for some x86 instructions which
specifically interleave high/low bytes for 32 and 64-bit values. This
corresponds to the preexisting specific lowerings for interleaving 8 and
16-bit values.

* x64: Add `shuffle` lowerings for `shufps`

This commit adds targeted lowerings for the `shuffle` instruction that
match the pattern that `shufps` supports. The `shufps` instruction
selects two elements from the first vector and two elements from the
second vector which means while it's not generally applicable it should
still be more useful than the catch-all lowering of `shuffle`.

* x64: Add shuffle support for `pshuf{l,h}w`

This commit adds special lowering cases for these instructions which
permute 16-bit values within a 128-bit value either within the upper or
lower half of the 128-bit value.

* x64: Specialize `shuffle` with an all-zeros immediate

Instead of loading the all-zeros immediate from a rip-relative address
at the end of the function instead generate a zero with a `pxor`
instruction and then use `pshufb` to do the broadcast.

* Review comments

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

@@ -1117,6 +1117,12 @@ pub enum SseOpcode {
     Xorpd,
     Phaddw,
     Phaddd,
+    Punpckhdq,
+    Punpckldq,
+    Punpckhqdq,
+    Punpcklqdq,
+    Pshuflw,
+    Pshufhw,
 }
 
 impl SseOpcode {
@@ -1256,7 +1262,13 @@ impl SseOpcode {
             | SseOpcode::Subpd
             | SseOpcode::Subsd
             | SseOpcode::Ucomisd
-            | SseOpcode::Xorpd => SSE2,
+            | SseOpcode::Xorpd
+            | SseOpcode::Punpckldq
+            | SseOpcode::Punpckhdq
+            | SseOpcode::Punpcklqdq
+            | SseOpcode::Punpckhqdq
+            | SseOpcode::Pshuflw
+            | SseOpcode::Pshufhw => SSE2,
 
             SseOpcode::Pabsb
             | SseOpcode::Pabsw
@@ -1501,6 +1513,12 @@ impl fmt::Debug for SseOpcode {
             SseOpcode::Xorpd => "xorpd",
             SseOpcode::Phaddw => "phaddw",
             SseOpcode::Phaddd => "phaddd",
+            SseOpcode::Punpckldq => "punpckldq",
+            SseOpcode::Punpckhdq => "punpckhdq",
+            SseOpcode::Punpcklqdq => "punpcklqdq",
+            SseOpcode::Punpckhqdq => "punpckhqdq",
+            SseOpcode::Pshuflw => "pshuflw",
+            SseOpcode::Pshufhw => "pshufhw",
         };
         write!(fmt, "{}", name)
     }
@@ -1669,7 +1687,13 @@ impl AvxOpcode {
             | AvxOpcode::Vcvttpd2dq
             | AvxOpcode::Vcvttps2dq
             | AvxOpcode::Vphaddw
-            | AvxOpcode::Vphaddd => {
+            | AvxOpcode::Vphaddd
+            | AvxOpcode::Vpunpckldq
+            | AvxOpcode::Vpunpckhdq
+            | AvxOpcode::Vpunpcklqdq
+            | AvxOpcode::Vpunpckhqdq
+            | AvxOpcode::Vpshuflw
+            | AvxOpcode::Vpshufhw => {
                 smallvec![InstructionSet::AVX]
             }
         }