From cd1eaf0116190ab72f3a792b74be99eda5dd31eb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Fri, 23 Jan 2015 13:12:44 +0100 Subject: 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. --- lib/compiler/test/trycatch_SUITE.erl | 1 - 1 file changed, 1 deletion(-) (limited to 'lib/compiler/test/trycatch_SUITE.erl') diff --git a/lib/compiler/test/trycatch_SUITE.erl b/lib/compiler/test/trycatch_SUITE.erl index b490257a6e..8ab618bb01 100644 --- a/lib/compiler/test/trycatch_SUITE.erl +++ b/lib/compiler/test/trycatch_SUITE.erl @@ -790,7 +790,6 @@ nested_after_1({X1,C1,V1}, nested_horrid(Config) when is_list(Config) -> - _V = {make_ref(),nested_horrid,4.711}, {[true,true],{[true,1.0],1.0}} = nested_horrid_1({true,void,void}, 1.0), ok. -- cgit v1.2.3