From 69109c0ace5e3ac831c3b0a5635f25317d3b28bf Mon Sep 17 00:00:00 2001 From: James Iry Date: Thu, 7 Mar 2013 15:05:35 -0800 Subject: Analyze constants to remove unnecessary branches This commit adds analysis and optimization of constants to remove unnecessary branches. It uses abstract interpretation to determine what constant(s) a particular stack slot or variable might or might not hold at a given spot and uses that knowledge to eliminate branches that cannot be taken. Its primary goal is null check removal, but it also works for other constants. Several tests are modified to include the new optimization phase. Two new tests are added. One verifies that branching still works as expected. The other verifies that branches are removed. --- test/files/neg/t6446-missing.check | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'test/files/neg/t6446-missing.check') diff --git a/test/files/neg/t6446-missing.check b/test/files/neg/t6446-missing.check index f976bf480e..6e5bdcf07c 100755 --- a/test/files/neg/t6446-missing.check +++ b/test/files/neg/t6446-missing.check @@ -26,6 +26,7 @@ superaccessors 6 add super accessors in traits and nested classes inliner 23 optimization: do inlining inlinehandlers 24 optimization: inline exception handlers closelim 25 optimization: eliminate uncalled closures - dce 26 optimization: eliminate dead code - jvm 27 generate JVM bytecode - terminal 28 The last phase in the compiler chain + constopt 26 optimization: optimize null and other constants + dce 27 optimization: eliminate dead code + jvm 28 generate JVM bytecode + terminal 29 The last phase in the compiler chain -- cgit v1.2.3