MFC r265925:

Upgrade our copy of llvm/clang to 3.4.1 release.  This release contains
mostly fixes, for the following upstream bugs:

http://llvm.org/PR16365 http://llvm.org/PR17473 http://llvm.org/PR18000
http://llvm.org/PR18068 http://llvm.org/PR18102 http://llvm.org/PR18165
http://llvm.org/PR18260 http://llvm.org/PR18290 http://llvm.org/PR18316
http://llvm.org/PR18460 http://llvm.org/PR18473 http://llvm.org/PR18515
http://llvm.org/PR18526 http://llvm.org/PR18600 http://llvm.org/PR18762
http://llvm.org/PR18773 http://llvm.org/PR18860 http://llvm.org/PR18994
http://llvm.org/PR19007 http://llvm.org/PR19010 http://llvm.org/PR19033
http://llvm.org/PR19059 http://llvm.org/PR19144 http://llvm.org/PR19326

1 files changed, 11 insertions, 2 deletions

diff --git a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5e75871..f9f6b18 100644
--- a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4191,13 +4191,22 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi,
         continue;
       }
 
-      // Process instructions only once (termination).
+      // Process instructions only once (termination). Each reduction cycle
+      // value must only be used once, except by phi nodes and min/max
+      // reductions which are represented as a cmp followed by a select.
+      ReductionInstDesc IgnoredVal(false, 0);
       if (VisitedInsts.insert(Usr)) {
         if (isa<PHINode>(Usr))
           PHIs.push_back(Usr);
         else
           NonPHIs.push_back(Usr);
-      }
+      } else if (!isa<PHINode>(Usr) &&
+                 ((!isa<FCmpInst>(Usr) &&
+                   !isa<ICmpInst>(Usr) &&
+                   !isa<SelectInst>(Usr)) ||
+                  !isMinMaxSelectCmpPattern(Usr, IgnoredVal).IsReduction))
+        return false;
+
       // Remember that we completed the cycle.
       if (Usr == Phi)
         FoundStartPHI = true;