cranelift: Remove copy instruction (#5125)

cranelift/codegen/src/ir/dfg.rs

@@ -1467,10 +1467,5 @@ mod tests {
 
         assert_eq!(pos.func.dfg.resolve_aliases(c2), c2);
         assert_eq!(pos.func.dfg.resolve_aliases(c), c2);
-
-        // Make a copy of the alias.
-        let c3 = pos.ins().copy(c);
-        // This does not see through copies.
-        assert_eq!(pos.func.dfg.resolve_aliases(c3), c3);
     }
 }

cranelift/codegen/src/isa/aarch64/lower.isle

@@ -2265,11 +2265,6 @@
                          (u8_from_uimm8 lane)))
       (mov_vec_elem vec val lane 0 (vector_size vty)))
 
-;;; Rules for `copy` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(rule (lower (copy x))
-      x)
-
 ;;; Rules for `stack_addr` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (rule (lower (stack_addr stack_slot offset))

cranelift/codegen/src/isa/aarch64/lower_inst.rs

@@ -157,8 +157,6 @@ pub(crate) fn lower_insn_to_regs(
 
         Opcode::IsNull | Opcode::IsInvalid => implemented_in_isle(ctx),
 
-        Opcode::Copy => implemented_in_isle(ctx),
-
         Opcode::Ireduce => implemented_in_isle(ctx),
 
         Opcode::Bmask => implemented_in_isle(ctx),

cranelift/codegen/src/isa/riscv64/lower.isle

@@ -535,10 +535,6 @@
       (_ Unit (emit (MInst.AtomicCas (gen_atomic_offset p ty) t0 dst (ext_int_if_need $false e ty) (gen_atomic_p p ty) x ty))))
     (writable_reg_to_reg dst)))
 
-;;;;;  Rules for `copy`;;;;;;;;;;;;;;;;;
-(rule (lower (has_type ty (copy x)))
-  (gen_move2 x ty ty))
-
 ;;;;;  Rules for `ireduce`;;;;;;;;;;;;;;;;;
 (rule
   (lower (has_type ty (ireduce x)))

cranelift/codegen/src/isa/s390x/lower.isle

@@ -46,12 +46,6 @@
       (invalid_reg))
 
 
-;;;; Rules for `copy` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(rule (lower (copy x))
-      x)
-
-
 ;;;; Rules for `iconcat` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (rule (lower (has_type (vr128_ty ty) (iconcat x y)))

cranelift/codegen/src/isa/s390x/lower.rs

@@ -43,7 +43,6 @@ impl LowerBackend for S390xBackend {
 
         match op {
             Opcode::Nop
-            | Opcode::Copy
             | Opcode::Iconst
             | Opcode::F32const
             | Opcode::F64const

cranelift/codegen/src/isa/x64/lower.rs

@@ -559,10 +559,6 @@ fn lower_insn_to_regs(
             panic!("table_addr should have been removed by legalization!");
         }
 
-        Opcode::Copy => {
-            panic!("Unused opcode should not be encountered.");
-        }
-
         Opcode::Trapz | Opcode::Trapnz | Opcode::ResumableTrapnz => {
             panic!("trapz / trapnz / resumable_trapnz should have been removed by legalization!");
         }