From c0c5943c3a2646a3383d974c2a1afcff8c5d16d3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Wed, 23 Sep 2015 07:23:15 +0200 Subject: beam_type: Improve optimization by keeping track of integers The ASN.1 compiler often generates code similar to: f(<<0:1,...>>) -> ...; f(<<1:1,...>>) -> .... Internally that will be rewritten to (conceptually): f(<>) -> case B of 0 -> case Tail of ... end; 1 -> case Tail of ... end; _ -> error(case_clause) end. Since B comes from a bit field of one bit, we know that the only possible values are 0 and 1. Therefore the error clause can be eliminated like this: f(<>) -> case B of 0 -> case Tail of ... end; _ -> case Tail of ... end end. Similarly, we can also a deduce the range for an integer from a 'band' operation with a literal integer. While we are at it, also add a test case to improve the coverage. --- lib/compiler/test/Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib/compiler/test/Makefile') diff --git a/lib/compiler/test/Makefile b/lib/compiler/test/Makefile index 6553d10077..0cd8618730 100644 --- a/lib/compiler/test/Makefile +++ b/lib/compiler/test/Makefile @@ -11,6 +11,7 @@ MODULES= \ beam_validator_SUITE \ beam_disasm_SUITE \ beam_except_SUITE \ + beam_type_SUITE \ beam_utils_SUITE \ bs_bincomp_SUITE \ bs_bit_binaries_SUITE \ @@ -43,6 +44,7 @@ NO_OPT= \ andor \ apply \ beam_except \ + beam_type \ beam_utils \ bs_construct \ bs_match \ -- cgit v1.2.3