[PATCH] D12951: [Unroll] When completely unrolling the loop, replace conditinal branches with unconditional.

[Michael Zolotukhin via llvm-commits]

mzolotukhin created this revision.
mzolotukhin added a reviewer: hfinkel.
mzolotukhin added a subscriber: llvm-commits.

I see no reasons why we don't do this at the moment (or I'm misreading
the code). Later clean-ups replace conditional branches anyway, but
that's unnecessary work. It might be even more relevant if we unroll
loops with relatively high trip-count.

Does this patch make sense?

http://reviews.llvm.org/D12951

Files:
  lib/Transforms/Utils/LoopUnroll.cpp

Index: lib/Transforms/Utils/LoopUnroll.cpp
===================================================================
--- lib/Transforms/Utils/LoopUnroll.cpp
+++ lib/Transforms/Utils/LoopUnroll.cpp
@@ -434,8 +434,9 @@
 
     // For a complete unroll, make the last iteration end with a branch
     // to the exit block.
-    if (CompletelyUnroll && j == 0) {
-      Dest = LoopExit;
+    if (CompletelyUnroll) {
+      if (j == 0)
+        Dest = LoopExit;
       NeedConditional = false;
     }
 


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