[mlir] Rewrite the internal representation of OpResult to be optimized for memory.

Summary:
This changes the implementation of OpResult to have some of the results be represented inline in Value, via a pointer int pair of Operation*+result number, and the rest being trailing objects on the main operation. The full details of the new representation is detailed in the proposal here:
https://groups.google.com/a/tensorflow.org/g/mlir/c/XXzzKhqqF_0/m/v6bKb08WCgAJ

The only difference between here and the above proposal is that we only steal 2-bits for the Value kind instead of 3. This means that we can only fit 2-results inline instead of 6. This allows for other users to steal the final bit for PointerUnion/etc. If necessary, we can always steal this bit back in the future to save more space if 3-6 results are common enough.

Reviewed By: jpienaar

Differential Revision: https://reviews.llvm.org/D72020

1 files changed, 1 insertions, 1 deletions

diff --git a/mlir/test/lib/Transforms/TestInlining.cpp b/mlir/test/lib/Transforms/TestInlining.cpp
index 36378283f8e..584849d0f51 100644
--- a/mlir/test/lib/Transforms/TestInlining.cpp
+++ b/mlir/test/lib/Transforms/TestInlining.cpp
@@ -46,7 +46,7 @@ struct Inliner : public FunctionPass<Inliner> {
       if (failed(inlineRegion(
               interface, &callee.body(), caller,
               llvm::to_vector<8>(caller.getArgOperands()),
-              llvm::to_vector<8>(caller.getResults()), caller.getLoc(),
+              SmallVector<Value, 8>(caller.getResults()), caller.getLoc(),
               /*shouldCloneInlinedRegion=*/!callee.getResult()->hasOneUse())))
         continue;