[InstCombine] Partially revert rL341674 due to PR38897.

Summary:
Revert min/max changes in rL341674 dues to high compile times causing timeouts (PR38897).
Checking in to unblock failing builds. Patch available for post-commit review and re-revert once resolved.
Working on a smaller reproducer for PR38897.

Reviewers: craig.topper, spatel

Subscribers: sanjoy, jlebar, llvm-commits

Differential Revision: https://reviews.llvm.org/D51897

llvm-svn: 341883

1 files changed, 8 insertions, 35 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index e710c486706..622b6eace5d 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1827,42 +1827,15 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
       }
 
       // MAX(~a, ~b) -> ~MIN(a, b)
-      // MAX(~a, C)  -> ~MIN(a, ~C)
       // MIN(~a, ~b) -> ~MAX(a, b)
-      // MIN(~a, C)  -> ~MAX(a, ~C)
-      auto moveNotAfterMinMax = [&](Value *X, Value *Y,
-                                    bool Swapped) -> Instruction * {
-        Value *A;
-        if (match(X, m_Not(m_Value(A))) && !X->hasNUsesOrMore(3) &&
-            // Passing false to only consider m_Not and constants.
-            IsFreeToInvert(Y, false)) {
-          Value *B = Builder.CreateNot(Y);
-          Value *NewMinMax = createMinMax(Builder, getInverseMinMaxFlavor(SPF),
-                                          A, B);
-          // Copy the profile metadata.
-          if (MDNode *MD = SI.getMetadata(LLVMContext::MD_prof)) {
-            cast<SelectInst>(NewMinMax)->setMetadata(LLVMContext::MD_prof, MD);
-            // Swap the metadata if the operands are swapped.
-            if (Swapped) {
-              assert(X == SI.getFalseValue() && Y == SI.getTrueValue() &&
-                     "Unexpected operands.");
-              cast<SelectInst>(NewMinMax)->swapProfMetadata();
-            } else {
-              assert(X == SI.getTrueValue() && Y == SI.getFalseValue() &&
-                     "Unexpected operands.");
-            }
-          }
-
-          return BinaryOperator::CreateNot(NewMinMax);
-        }
-
-        return nullptr;
-      };
-
-      if (Instruction *I = moveNotAfterMinMax(LHS, RHS, /*Swapped*/false))
-        return I;
-      if (Instruction *I = moveNotAfterMinMax(RHS, LHS, /*Swapped*/true))
-        return I;
+      Value *A, *B;
+      if (match(LHS, m_Not(m_Value(A))) && match(RHS, m_Not(m_Value(B))) &&
+          (!LHS->hasNUsesOrMore(3) || !RHS->hasNUsesOrMore(3))) {
+        CmpInst::Predicate InvertedPred = getInverseMinMaxPred(SPF);
+        Value *InvertedCmp = Builder.CreateICmp(InvertedPred, A, B);
+        Value *NewSel = Builder.CreateSelect(InvertedCmp, A, B);
+        return BinaryOperator::CreateNot(NewSel);
+      }
 
       if (Instruction *I = factorizeMinMaxTree(SPF, LHS, RHS, Builder))
         return I;