Add a new memcpy propagation pass

[vaivaswatha]

Description

For the Sway code in #7344, the IR after #7381 and after this PR is shown here:

After #7381, before this PR

   fn wrapper_1(__ret_value: __ptr { b256 }) -> (), !17 {
        local { u64, ( () | { b256 } ) } __matched_value_4
        local { u64, ( () | { b256 } ) } __ret_val
        local { u64, ( () | { b256 } ) } self_

        entry(__ret_value: __ptr { b256 }):
        v0 = get_local __ptr { u64, ( () | { b256 } ) }, __ret_val
        v1 = call return_option_5(v0)
        v2 = get_local __ptr { u64, ( () | { b256 } ) }, self_, !20
        mem_copy_val v2, v0
        v3 = get_local __ptr { u64, ( () | { b256 } ) }, self_, !23
        v4 = get_local __ptr { u64, ( () | { b256 } ) }, __matched_value_4, !25
        mem_copy_val v4, v3
        v5 = get_local __ptr { u64, ( () | { b256 } ) }, self_
        v6 = const u64 0
        v7 = get_elem_ptr v5, __ptr u64, v6
        v8 = load v7, !20
        v9 = const u64 1, !22
        v10 = cmp eq v8 v9, !28
        cbr v10, unwrap_2_block0(), unwrap_2_block1(), !29

        unwrap_2_block0():
        v11 = get_local __ptr { u64, ( () | { b256 } ) }, __matched_value_4, !30
        v12 = const u64 1
        v13 = const u64 1
        v14 = get_elem_ptr v11, __ptr { b256 }, v12, v13, !20
        mem_copy_val __ret_value, v14
        v15 = const unit ()
        ret () v15

        unwrap_2_block1():
        v16 = const u64 0, !31
        revert v16, !36
    }

    fn return_option_5(__ret_value: __ptr { u64, ( () | { b256 } ) }) -> (), !39 {
        local { u64, ( () | { b256 } ) } __anon_0

        entry(__ret_value: __ptr { u64, ( () | { b256 } ) }):
        v0 = get_local __ptr { u64, ( () | { b256 } ) }, __anon_0, !40
        v1 = const u64 0
        v2 = get_elem_ptr v0, __ptr u64, v1, !40
        v3 = const u64 0, !40
        store v3 to v2, !40
        mem_copy_val __ret_value, v0
        v4 = const unit ()
        ret () v4
    }

After this PR

    fn wrapper_1(__ret_value: __ptr { b256 }) -> (), !17 {
        local { u64, ( () | { b256 } ) } __ret_val

        entry(__ret_value: __ptr { b256 }):
        v0 = get_local __ptr { u64, ( () | { b256 } ) }, __ret_val
        v1 = call return_option_5(v0)
        mem_copy_val __ret_value, v0
        v2 = const u64 0
        v3 = get_elem_ptr __ret_value, __ptr u64, v2
        v4 = load v3, !20
        v5 = const u64 1, !22
        v6 = cmp eq v4 v5, !25
        cbr v6, unwrap_2_block0(), unwrap_2_block1(), !26

        unwrap_2_block0():
        v7 = const unit ()
        ret () v7

        unwrap_2_block1():
        v8 = const u64 0, !27
        revert v8, !32
    }

    fn return_option_5(__ret_value: __ptr { u64, ( () | { b256 } ) }) -> (), !35 {
        entry(__ret_value: __ptr { u64, ( () | { b256 } ) }):
        v0 = const u64 0
        v1 = get_elem_ptr __ret_value, __ptr u64, v0, !36
        v2 = const u64 0, !36
        store v2 to v1, !36
        v3 = const unit ()
        ret () v3
    }

wrapper_1, which had 3 memcpys now only has 1, and return_option_5 which had one, now has none.

Closes #7344.

[codspeed-hq]

CodSpeed Performance Report

Merging #7443 will not alter performance

_{Comparing vaivaswatha/memcpy_prop_new (96127a8) with master (74bab18)}

Summary

✅ 25 untouched