diff options
Diffstat (limited to 'lib/compiler')
| -rw-r--r-- | lib/compiler/src/beam_ssa_type.erl | 23 | ||||
| -rw-r--r-- | lib/compiler/test/trycatch_SUITE.erl | 27 |
2 files changed, 46 insertions, 4 deletions
diff --git a/lib/compiler/src/beam_ssa_type.erl b/lib/compiler/src/beam_ssa_type.erl index c01ea4af91..06b42f1928 100644 --- a/lib/compiler/src/beam_ssa_type.erl +++ b/lib/compiler/src/beam_ssa_type.erl @@ -267,10 +267,29 @@ opt_is([#b_set{op=call,args=Args0,dst=Dst}=I0|Is], I1 = beam_ssa:normalize(I0#b_set{args=Args}), {Ts1,Ds,Fdb,I2} = opt_call(I1, D, Ts0, Ds0, Fdb0), case {map_get(Dst, Ts1),Is} of - {_,[#b_set{op=succeeded}]} -> + {Type,[#b_set{op=succeeded}]} when Type =/= none -> %% This call instruction is inside a try/catch - %% block. Don't attempt to optimize it. + %% block. Don't attempt to simplify it. opt_is(Is, Ts1, Ds, Fdb, D, Sub0, [I2|Acc]); + {none,[#b_set{op=succeeded}]} -> + %% This call instruction is inside a try/catch + %% block, but we know it will never return and + %% later optimizations may try to exploit that. + %% + %% For example, if we have an expression that + %% either returns this call or a tuple, we know + %% that the expression always returns a tuple + %% and can turn a later element/3 into + %% get_tuple_element. + %% + %% This is sound but difficult to validate in a + %% meaningful way as try/catch currently forces + %% us to maintain the illusion that the success + %% block is reachable even when its not, so we + %% disable the optimization to keep things + %% simple. + Ts = Ts1#{ Dst := any }, + opt_is(Is, Ts, Ds, Fdb, D, Sub0, [I2|Acc]); {none,_} -> %% This call never returns. The rest of the %% instructions will not be executed. diff --git a/lib/compiler/test/trycatch_SUITE.erl b/lib/compiler/test/trycatch_SUITE.erl index 8f9cd9ab1e..539f9d69fa 100644 --- a/lib/compiler/test/trycatch_SUITE.erl +++ b/lib/compiler/test/trycatch_SUITE.erl @@ -27,7 +27,8 @@ nested_horrid/1,last_call_optimization/1,bool/1, plain_catch_coverage/1,andalso_orelse/1,get_in_try/1, hockey/1,handle_info/1,catch_in_catch/1,grab_bag/1, - stacktrace/1,nested_stacktrace/1,raise/1]). + stacktrace/1,nested_stacktrace/1,raise/1, + no_return_in_try_block/1]). -include_lib("common_test/include/ct.hrl"). @@ -43,7 +44,8 @@ groups() -> nested_after,nested_horrid,last_call_optimization, bool,plain_catch_coverage,andalso_orelse,get_in_try, hockey,handle_info,catch_in_catch,grab_bag, - stacktrace,nested_stacktrace,raise]}]. + stacktrace,nested_stacktrace,raise, + no_return_in_try_block]}]. init_per_suite(Config) -> @@ -1287,5 +1289,26 @@ do_test_raise_4(Expr) -> erlang:raise(exit, {exception,C,E,Stk}, Stk) end. +no_return_in_try_block(Config) when is_list(Config) -> + 1.0 = no_return_in_try_block_1(0), + 1.0 = no_return_in_try_block_1(0.0), + + gurka = no_return_in_try_block_1(gurka), + [] = no_return_in_try_block_1([]), + + ok. + +no_return_in_try_block_1(H) -> + try + Float = if + is_number(H) -> float(H); + true -> no_return() + end, + Float + 1 + catch + throw:no_return -> H + end. + +no_return() -> throw(no_return). id(I) -> I. |