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| author | Craig Topper <craig.topper@intel.com> | 2019-08-20 22:12:50 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2019-08-20 22:12:50 +0000 |
| commit | ba375263e868583b709f5b3193d3286648d2f2ab (patch) | |
| tree | 39dea2e87f37d1bf32cdb44db8a58a8be863ccce /lldb/packages/Python/lldbsuite/test/expression_command/context-object-objc | |
| parent | be6c0794197558c7ca9775cd7c0b97e816c2c5e2 (diff) | |
| download | bcm5719-llvm-ba375263e868583b709f5b3193d3286648d2f2ab.tar.gz bcm5719-llvm-ba375263e868583b709f5b3193d3286648d2f2ab.zip | |
[DAGCombiner][X86] Teach visitCONCAT_VECTORS to combine (concat_vectors (concat_vectors X, Y), undef)) -> (concat_vectors X, Y, undef, undef)
I also had to add a new combine to X86's combineExtractSubvector to prevent a regression.
This helps our vXi1 code see the full concat operation and allow it optimize undef to a zero if there is already a zero in the concat. This helped us use a movzx instead of an AND in some of the tests. In those tests, one concat comes from SelectionDAGBuilder and the second comes from type legalization of v4i1->i4 bitcasts which uses an additional concat. Though these changes weren't my original motivation.
I'm looking at making X86ISelLowering's narrowShuffle emit a concat_vectors instead of an insert_subvector since concat_vectors is more canonical during early DAG combine. This patch helps prevent a regression from my experiments with that.
Differential Revision: https://reviews.llvm.org/D66456
llvm-svn: 369459
Diffstat (limited to 'lldb/packages/Python/lldbsuite/test/expression_command/context-object-objc')
0 files changed, 0 insertions, 0 deletions
