From e12b7d5331c58b41db06cadfa4af75b78b62a2b1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Fri, 20 Dec 2013 15:28:06 +0100 Subject: Generalize optimizations of case statements Case expressions such as: case {Expr1,Expr} of {V1,V2} -> ... end are already optimized to not actually build the tuple. Generalize the optimization to avoid building any kind of composite term, such as: case {ok,[A,B]} of {ok,[X,Y]} -> ... end We don't expect programmers to write such code directly, but inlining can produce such code. We need to be careful about the warnings we produce. If the case expression is a literal, it is expected that no warnings should be produced for clauses that don't match. We must make sure that we continue to suppress those warnings. --- lib/compiler/test/core_fold_SUITE.erl | 9 +++++++++ lib/compiler/test/warnings_SUITE.erl | 1 + 2 files changed, 10 insertions(+) (limited to 'lib/compiler/test') diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl index a5a4e62a42..69f61a046f 100644 --- a/lib/compiler/test/core_fold_SUITE.erl +++ b/lib/compiler/test/core_fold_SUITE.erl @@ -249,6 +249,12 @@ coverage(Config) when is_list(Config) -> case list_to_pid("<0.42.0>") of Pid when is_pid(Pid) -> ok end, + + %% Cover the non-variable case in bsm_do_an/4. + ok = bsm_an_inlined(<<1>>, Config), + error = bsm_an_inlined(<<1,2,3>>, Config), + error = bsm_an_inlined([], Config), + ok. cover_will_match_list_type(A) -> @@ -290,6 +296,9 @@ cover_is_safe_bool_expr(X) -> false end. +bsm_an_inlined(<<_:8>>, _) -> ok; +bsm_an_inlined(_, _) -> error. + id(I) -> I. unused_multiple_values_error(Config) when is_list(Config) -> diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl index 810b2b48c9..7186956603 100644 --- a/lib/compiler/test/warnings_SUITE.erl +++ b/lib/compiler/test/warnings_SUITE.erl @@ -117,6 +117,7 @@ pattern2(Config) when is_list(Config) -> Source, [nowarn_unused_vars], {warnings,[{2,sys_core_fold,{nomatch_shadow,1}}, + {4,sys_core_fold,no_clause_match}, {5,sys_core_fold,nomatch_clause_type}, {6,sys_core_fold,nomatch_clause_type}]}}], ?line [] = run(Config, Ts), -- cgit v1.2.3