[PATCH] D30309: CodeGen: BlockPlacement: Precompute layout for chains of triangles.

[David Li via Phabricator via llvm-commits]

davidxl added inline comments.


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Comment at: lib/CodeGen/MachineBlockPlacement.cpp:152
+             "triangle tail duplication heuristic to kick in. 0 to disable."),
+    cl::init(2),
+    cl::Hidden);
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Should the default be 3?


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Comment at: lib/CodeGen/MachineBlockPlacement.cpp:1061
+///    longer chains)
+/// 2) The chains are statically correlated. Branch probabilities have a very
+///    U-shaped distribution. If the branches in a chain are all from the same
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2) This is not entirely true --  it depends on the length the chain (e.g, when branch proabiity to Pdom blocks are low).  Perhaps remove 2).


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Comment at: test/CodeGen/PowerPC/tail-dup-layout.ll:59
   call void @a()
-  call void @a()
-  call void @a()
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Why changing this test?


https://reviews.llvm.org/D30309