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path: root/test/CodeGen/X86/dagcombine-shifts.ll
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* Fix edge condition in DAGCombiner to improve codegen of shift sequences.Andrea Di Biagio2013-10-17
| | | | | | | | | | | | | When canonicalizing dags according to the rule (shl (zext (shr X, c1) ), c1) ==> (zext (shl (shr X, c1), c1)) remember to add the new shl dag to the DAGCombiner worklist of nodes. If we don't explicitly add it to the worklist of nodes to visit, we may not trigger later on the rule that folds the shift left + logical shift right into a AND instruction with bitmask. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192883 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove superfluous comment accidentally checked-in.Andrea Di Biagio2013-09-27
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191513 91177308-0d34-0410-b5e6-96231b3b80d8
* Re-apply the change from r191393 with fix for pr17380.Andrea Di Biagio2013-09-27
| | | | | | | | | | | This change fixes the problem reported in pr17380 and re-add the dagcombine transformation ensuring that the value types are always legal if the transformation is triggered after Legalization took place. Added the test case from pr17380. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191509 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert r191393 since it caused pr17380.Andrea Di Biagio2013-09-26
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191438 91177308-0d34-0410-b5e6-96231b3b80d8
* Teach DAGCombiner how to canonicalize dags according to the ruleAndrea Di Biagio2013-09-25
(shl (zext (shr A, X)), X) => (zext (shl (shr A, X), X)). The rule only triggers when there are no other uses of the zext to avoid materializing more instructions. This helps the DAGCombiner understand that the shl/shr sequence can then be converted into an and instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191393 91177308-0d34-0410-b5e6-96231b3b80d8