nak: Make BindlessSSA store [SSAValue; 2]

This reduces the size of ir::Src from 40 bytes down to 32 bytes. This
makes the size of ir::Op fall from 272 bytes down to 232 bytes, meaning
we save 40 bytes per instruction.

Reviewed-by: Mary Guillemard <mary@mary.zone>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37130>

src/nouveau/compiler/nak/from_nir.rs

@@ -3343,7 +3343,7 @@ impl<'a> ShaderFromNir<'a> {
                 let (off, off_imm) = self.get_cbuf_addr_offset(&srcs[1]);
 
                 let cb = CBufRef {
-                    buf: CBuf::BindlessSSA(handle),
+                    buf: CBuf::BindlessSSA(handle[..].try_into().unwrap()),
                     offset: off_imm,
                 };
 

src/nouveau/compiler/nak/ir.rs

@@ -535,7 +535,7 @@ pub enum CBuf {
     Binding(u8),
 
     #[allow(dead_code)]
-    BindlessSSA(SSARef),
+    BindlessSSA([SSAValue; 2]),
 
     #[allow(dead_code)]
     BindlessUGPR(RegRef),
@@ -545,7 +545,7 @@ impl fmt::Display for CBuf {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CBuf::Binding(idx) => write!(f, "c[{:#x}]", idx),
-            CBuf::BindlessSSA(v) => write!(f, "cx[{}]", v),
+            CBuf::BindlessSSA(v) => write!(f, "cx[{{{}, {}}}]", v[0], v[1]),
             CBuf::BindlessUGPR(r) => write!(f, "cx[{}]", r),
         }
     }
@@ -683,7 +683,7 @@ impl SrcRef {
             | SrcRef::Reg(_) => &[],
             SrcRef::CBuf(cb) => match &cb.buf {
                 CBuf::Binding(_) | CBuf::BindlessUGPR(_) => &[],
-                CBuf::BindlessSSA(ssa) => ssa.deref(),
+                CBuf::BindlessSSA(ssa) => &ssa[..],
             },
             SrcRef::SSA(ssa) => ssa.deref(),
         }
@@ -699,7 +699,7 @@ impl SrcRef {
             | SrcRef::Reg(_) => &mut [],
             SrcRef::CBuf(cb) => match &mut cb.buf {
                 CBuf::Binding(_) | CBuf::BindlessUGPR(_) => &mut [],
-                CBuf::BindlessSSA(ssa) => ssa.deref_mut(),
+                CBuf::BindlessSSA(ssa) => &mut ssa[..],
             },
             SrcRef::SSA(ssa) => ssa.deref_mut(),
         }

src/nouveau/compiler/nak/legalize.rs

@@ -452,7 +452,7 @@ fn legalize_instr(
                 SrcRef::CBuf(CBufRef {
                     buf: CBuf::BindlessSSA(handle),
                     ..
-                }) => assert!(pinned.contains(handle)),
+                }) => assert!(pinned.contains(&SSARef::new(handle))),
                 _ => (),
             }
         }