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author | Björn Gustavsson <[email protected]> | 2015-01-23 13:12:44 +0100 |
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committer | Björn Gustavsson <[email protected]> | 2015-02-03 08:40:49 +0100 |
commit | cd1eaf0116190ab72f3a792b74be99eda5dd31eb (patch) | |
tree | 0d036a4c6d102d1bd5859c894dd163b6a0a8f0ad /lib/compiler/test/core_fold_SUITE.erl | |
parent | 8c3baeb1275c2e6a316d3b5203e0598906785cdb (diff) | |
download | otp-cd1eaf0116190ab72f3a792b74be99eda5dd31eb.tar.gz otp-cd1eaf0116190ab72f3a792b74be99eda5dd31eb.tar.bz2 otp-cd1eaf0116190ab72f3a792b74be99eda5dd31eb.zip |
sys_core_fold: Optimize let statements more aggressively
I originally decided that in 'value' context, rewriting a let statement
where the variables were not in the body to a sequence was not worth
it, because the variables would be unused in only one let in a
thousand lets (roughly).
I have reconsidered.
The main reason is that if we do the rewrite, core_lib:is_var_used/2
will be used much more frequently, which will help us to find bugs
in it sooner.
Another reason is that the way letify/2 is currently implemented
with its own calls to core_lib:is_var_used/2 is only safe as long
as all the bindings are independent of each other. We could make
letify/2 smarter, but if we introduce this new optimization there
is no need.
Measuring compilation speed, I have not seen any significant slowdown.
It seems that although core_lib:is_var_used/2 is called much more
frequently, most calls will be fast because is_var_used/2 will quickly
find a use of the variable.
Also add a test case to cover a line opt_guard_try/1 that was
no longer covered.
Diffstat (limited to 'lib/compiler/test/core_fold_SUITE.erl')
-rw-r--r-- | lib/compiler/test/core_fold_SUITE.erl | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl index ce1aea5de0..bca8afb1b0 100644 --- a/lib/compiler/test/core_fold_SUITE.erl +++ b/lib/compiler/test/core_fold_SUITE.erl @@ -242,6 +242,8 @@ do_guard_try_catch(K, V) -> false end. +-record(cover_opt_guard_try, {list=[]}). + coverage(Config) when is_list(Config) -> ?line {'EXIT',{{case_clause,{a,b,c}},_}} = (catch cover_will_match_list_type({a,b,c})), @@ -251,6 +253,9 @@ coverage(Config) when is_list(Config) -> ?line error = cover_will_match_lit_list(), {ok,[a]} = cover_is_safe_bool_expr(a), + ok = cover_opt_guard_try(#cover_opt_guard_try{list=[a]}), + error = cover_opt_guard_try(#cover_opt_guard_try{list=[]}), + %% Make sure that we don't attempt to make literals %% out of pids. (Putting a pid into a #c_literal{} %% would crash later compiler passes.) @@ -304,6 +309,14 @@ cover_is_safe_bool_expr(X) -> false end. +cover_opt_guard_try(Msg) -> + if + length(Msg#cover_opt_guard_try.list) =/= 1 -> + error; + true -> + ok + end. + bsm_an_inlined(<<_:8>>, _) -> ok; bsm_an_inlined(_, _) -> error. |