[PATCH] D22892: Codegen: MachineBlockPlacement Improve probability layout.

[David Li via llvm-commits]

davidxl accepted this revision.
davidxl added a comment.
This revision is now accepted and ready to land.

lgtm with the test change suggestion.


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Comment at: test/CodeGen/X86/block-placement.ll:1334
@@ +1333,3 @@
+define void @test_forked_hot_diamond_gets_cold(i32* %a) {
+; Test that a hot-branch with probability > 80% followed by a 50/50 branch
+; will place the cold predecessor if the probability for the fallthrough
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I think we probably don't need to test the exact boundary condition here to make the test more robust (say when hotprob is tuned).  I suggest making the branch at then1 block to have (60%, 40%) branch prob distribution to make the case more obvious (such that the backward branch prob of edge then2->fork1 is around 70%.


https://reviews.llvm.org/D22892