remove unsigned_add_overflow_condition (#6199)

cranelift/wasm/src/environ/dummy.rs

@@ -655,10 +655,6 @@ impl<'dummy_environment> FuncEnvironment for DummyFuncEnvironment<'dummy_environ
     ) -> WasmResult<ir::Value> {
         Ok(pos.ins().iconst(I32, 0))
     }
-
-    fn unsigned_add_overflow_condition(&self) -> ir::condcodes::IntCC {
-        unimplemented!()
-    }
 }
 
 impl TargetEnvironment for DummyEnvironment {

cranelift/wasm/src/environ/spec.rs

@@ -522,10 +522,6 @@ pub trait FuncEnvironment: TargetEnvironment {
         Ok(())
     }
 
-    /// Returns the target ISA's condition to check for unsigned addition
-    /// overflowing.
-    fn unsigned_add_overflow_condition(&self) -> ir::condcodes::IntCC;
-
     /// Whether or not to force relaxed simd instructions to have deterministic
     /// lowerings meaning they will produce the same results across all hosts,
     /// regardless of the cost to performance.