[PATCH] Loop Vectorizer Debug Info

[Renato Golin]

Hi nadav,

Just moving code around to make it easier to spot basic-blocks of loops that can't be if-converted. No functional change.

http://llvm-reviews.chandlerc.com/D1897

Files:
  lib/Transforms/Vectorize/LoopVectorize.cpp

Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2745,19 +2745,17 @@
   if (!TheLoop->getExitingBlock())
     return false;
 
-  unsigned NumBlocks = TheLoop->getNumBlocks();
+  // We need to have a loop header.
+  DEBUG(dbgs() << "LV: Found a loop: " <<
+        TheLoop->getHeader()->getName() << '\n');
 
   // Check if we can if-convert non single-bb loops.
+  unsigned NumBlocks = TheLoop->getNumBlocks();
   if (NumBlocks != 1 && !canVectorizeWithIfConvert()) {
     DEBUG(dbgs() << "LV: Can't if-convert the loop.\n");
     return false;
   }
 
-  // We need to have a loop header.
-  BasicBlock *Latch = TheLoop->getLoopLatch();
-  DEBUG(dbgs() << "LV: Found a loop: " <<
-        TheLoop->getHeader()->getName() << '\n');
-
   // ScalarEvolution needs to be able to find the exit count.
   const SCEV *ExitCount = SE->getBackedgeTakenCount(TheLoop);
   if (ExitCount == SE->getCouldNotCompute()) {
@@ -2766,6 +2764,7 @@
   }
 
   // Do not loop-vectorize loops with a tiny trip count.
+  BasicBlock *Latch = TheLoop->getLoopLatch();
   unsigned TC = SE->getSmallConstantTripCount(TheLoop, Latch);
   if (TC > 0u && TC < TinyTripCountVectorThreshold) {
     DEBUG(dbgs() << "LV: Found a loop with a very small trip count. " <<
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