1 files changed, 17 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 33951e66497a1..80c6595904e11 100644
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1167,6 +1167,23 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
   if (Instruction *I = canonicalizeSelectToShuffle(SI))
     return I;
 
+  // Canonicalize a one-use integer compare with a non-canonical predicate by
+  // inverting the predicate and swapping the select operands. This matches a
+  // compare canonicalization for conditional branches.
+  // TODO: Should we do the same for FP compares?
+  CmpInst::Predicate Pred;
+  if (match(CondVal, m_OneUse(m_ICmp(Pred, m_Value(), m_Value()))) &&
+      !isCanonicalPredicate(Pred)) {
+    // Swap true/false values and condition.
+    CmpInst *Cond = cast<CmpInst>(CondVal);
+    Cond->setPredicate(CmpInst::getInversePredicate(Pred));
+    SI.setOperand(1, FalseVal);
+    SI.setOperand(2, TrueVal);
+    SI.swapProfMetadata();
+    Worklist.Add(Cond);
+    return &SI;
+  }
+
   if (SelType->getScalarType()->isIntegerTy(1) &&
       TrueVal->getType() == CondVal->getType()) {
     if (match(TrueVal, m_One())) {