1 files changed, 0 insertions, 45 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 80ae406604b..3bfe49bbae3 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -114,15 +114,6 @@ static bool SubWithOverflow(Constant *&Result, Constant *In1,
                         IsSigned);
 }
 
-/// Given an icmp instruction, return true if any use of this comparison is a
-/// branch on sign bit comparison.
-static bool isBranchOnSignBitCheck(ICmpInst &I, bool isSignBit) {
-  for (auto *U : I.users())
-    if (isa<BranchInst>(U))
-      return isSignBit;
-  return false;
-}
-
 /// isSignBitCheck - Given an exploded icmp instruction, return true if the
 /// comparison only checks the sign bit.  If it only checks the sign bit, set
 /// TrueIfSigned if the result of the comparison is true when the input value is
@@ -3293,42 +3284,6 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
     // bits, if it is a sign bit comparison, it only demands the sign bit.
     bool UnusedBit;
     isSignBit = isSignBitCheck(I.getPredicate(), CI, UnusedBit);
-
-    // Canonicalize icmp instructions based on dominating conditions.
-    BasicBlock *Parent = I.getParent();
-    BasicBlock *Dom = Parent->getSinglePredecessor();
-    auto *BI = Dom ? dyn_cast<BranchInst>(Dom->getTerminator()) : nullptr;
-    ICmpInst::Predicate Pred;
-    BasicBlock *TrueBB, *FalseBB;
-    ConstantInt *CI2;
-    if (BI && match(BI, m_Br(m_ICmp(Pred, m_Specific(Op0), m_ConstantInt(CI2)),
-                             TrueBB, FalseBB)) &&
-        TrueBB != FalseBB) {
-      ConstantRange CR = ConstantRange::makeAllowedICmpRegion(I.getPredicate(),
-                                                              CI->getValue());
-      ConstantRange DominatingCR =
-          (Parent == TrueBB)
-              ? ConstantRange::makeExactICmpRegion(Pred, CI2->getValue())
-              : ConstantRange::makeExactICmpRegion(
-                    CmpInst::getInversePredicate(Pred), CI2->getValue());
-      ConstantRange Intersection = DominatingCR.intersectWith(CR);
-      ConstantRange Difference = DominatingCR.difference(CR);
-      if (Intersection.isEmptySet())
-        return replaceInstUsesWith(I, Builder->getFalse());
-      if (Difference.isEmptySet())
-        return replaceInstUsesWith(I, Builder->getTrue());
-      // Canonicalizing a sign bit comparison that gets used in a branch,
-      // pessimizes codegen by generating branch on zero instruction instead
-      // of a test and branch. So we avoid canonicalizing in such situations
-      // because test and branch instruction has better branch displacement
-      // than compare and branch instruction.
-      if (!isBranchOnSignBitCheck(I, isSignBit) && !I.isEquality()) {
-        if (auto *AI = Intersection.getSingleElement())
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Builder->getInt(*AI));
-        if (auto *AD = Difference.getSingleElement())
-          return new ICmpInst(ICmpInst::ICMP_NE, Op0, Builder->getInt(*AD));
-      }
-    }
   }
 
   // See if we can fold the comparison based on range information we can get