Duncan Sands 1faa8712c9 At -O123 the early-cse pass is run before instcombine has run. According to my ... auto-simplier the transform most missed by early-cse is (zext X) != 0 -> X != 0. This patch adds this transform and some related logic to InstructionSimplify and removes some of the logic from instcombine (unfortunately not all because there are several situations in which instcombine can improve things by making new instructions, whereas instsimplify is not allowed to do this). At -O2 this often results in more than 15% more simplifications by early-cse, and results in hundreds of lines of bitcode being eliminated from the testsuite. I did see some small negative effects in the testsuite, for example a few additional instructions in three programs. One program, 483.xalancbmk, got an additional 35 instructions, which seems to be due to a function getting an additional instruction and then being inlined all over the place. llvm-svn: 123911		2011-01-20 13:21:55 +00:00
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2010-12-20-Boolean.ll	Rename this test.	2011-01-14 14:16:33 +00:00
2010-12-20-Distribute.ll	Simplify (X<<1)-X into X. According to my auto-simplier this is the most common missed	2011-01-18 09:24:58 +00:00
2010-12-20-Reassociate.ll	For completeness, generalize the (X + Y) - Y -> X transform and add X - (X + 1) -> -1.	2011-01-18 11:50:19 +00:00
2011-01-14-Thread.ll	Factorize common code out of the InstructionSimplify shift logic. Add in	2011-01-14 14:44:12 +00:00
2011-01-18-Compare.ll	At -O123 the early-cse pass is run before instcombine has run. According to my	2011-01-20 13:21:55 +00:00
dg.exp	Add generic simplification of associative operations, generalizing	2010-12-21 08:49:00 +00:00