[PATCH] D23824: [ADCE] Add handling of PHI nodes when removing control flow

[David Callahan via llvm-commits]

david2050 marked an inline comment as done.

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Comment at: lib/Transforms/Scalar/ADCE.cpp:450
@@ +449,3 @@
+    // force some predecessors live (such as "br label %end" in block
+    // "cond.false") to correctly model the control dependence.
+    
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I ran an experiment by prioritize that we keep the lexically last defined value. This should bias toward forcing live earlier branch decisions which are likely to be forced live anyway if we mark a later branch live. This had minimal impact on the my set of C++ tests (two changes, in different directions).


https://reviews.llvm.org/D23824