llvm-project/llvm/lib/Transforms/Vectorize
Craig Topper b45eabcf82 [ValueTracking] Introduce a KnownBits struct to wrap the two APInts for computeKnownBits
This patch introduces a new KnownBits struct that wraps the two APInt used by computeKnownBits. This allows us to treat them as more of a unit.

Initially I've just altered the signatures of computeKnownBits and InstCombine's simplifyDemandedBits to pass a KnownBits reference instead of two separate APInt references. I'll do similar to the SelectionDAG version of computeKnownBits/simplifyDemandedBits as a separate patch.

I've added a constructor that allows initializing both APInts to the same bit width with a starting value of 0. This reduces the repeated pattern of initializing both APInts. Once place default constructed the APInts so I added a default constructor for those cases.

Going forward I would like to add more methods that will work on the pairs. For example trunc, zext, and sext occur on both APInts together in several places. We should probably add a clear method that can be used to clear both pieces. Maybe a method to check for conflicting information. A method to return (Zero|One) so we don't write it out everywhere. Maybe a method for (Zero|One).isAllOnesValue() to determine if all bits are known. I'm sure there are many other methods we can come up with.

Differential Revision: https://reviews.llvm.org/D32376

llvm-svn: 301432
2017-04-26 16:39:58 +00:00
..
BBVectorize.cpp [SystemZ] TargetTransformInfo cost functions implemented. 2017-04-12 11:49:08 +00:00
CMakeLists.txt [CMake] NFC. Updating CMake dependency specifications 2016-11-17 04:36:50 +00:00
LLVMBuild.txt
LoadStoreVectorizer.cpp [ValueTracking] Introduce a KnownBits struct to wrap the two APInts for computeKnownBits 2017-04-26 16:39:58 +00:00
LoopVectorize.cpp [LV] Handle external uses of floating-point induction variables 2017-04-26 16:23:02 +00:00
SLPVectorizer.cpp Reverts commit r301424, r301425 and r301426 2017-04-26 16:37:05 +00:00
Vectorize.cpp Add LoadStoreVectorizer pass 2016-06-30 23:11:38 +00:00