[InstCombine] Fold X Pred C2 ? X BOp C1 : C2 BOp C1 to min/max(X, C2) BOp C1 (#116888)

Fixes #82414.

General Proof: https://alive2.llvm.org/ce/z/ERjNs4 
Proof for Tests: https://alive2.llvm.org/ce/z/K-934G

This PR transforms `select` instructions of the form `select (Cmp X C1)
(BOp X C2) C3` to `BOp (min/max X C1) C2` iff `C3 == BOp C1 C2`.

This helps in eliminating a noop loop in
rust-lang/rust#123845 but does not improve
optimizations.

Author: veera-sivarajan

clang/test/CodeGen/attr-counted-by.c

@@ -119,9 +119,8 @@ void test1(struct annotated *p, int index, int val) {
 // SANITIZE-WITH-ATTR:       cont3:
 // SANITIZE-WITH-ATTR-NEXT:    [[ARRAY:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 12
 // SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw [0 x i32], ptr [[ARRAY]], i64 0, i64 [[INDEX]]
-// SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD]], 2
-// SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i32 [[DOT_COUNTED_BY_LOAD]], 0
-// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP2]]
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = tail call i32 @llvm.smax.i32(i32 [[DOT_COUNTED_BY_LOAD]], i32 0)
+// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[TMP2]], 2
 // SANITIZE-WITH-ATTR-NEXT:    store i32 [[CONV]], ptr [[ARRAYIDX]], align 4, !tbaa [[TBAA4]]
 // SANITIZE-WITH-ATTR-NEXT:    ret void
 //
@@ -130,9 +129,8 @@ void test1(struct annotated *p, int index, int val) {
 // NO-SANITIZE-WITH-ATTR-NEXT:  entry:
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 8
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i32, ptr [[DOT_COUNTED_BY_GEP]], align 4
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD]], 2
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i32 [[DOT_COUNTED_BY_LOAD]], 0
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP0]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = tail call i32 @llvm.smax.i32(i32 [[DOT_COUNTED_BY_LOAD]], i32 0)
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[TMP0]], 2
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAY:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 12
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw [0 x i32], ptr [[ARRAY]], i64 0, i64 [[INDEX]]
 // NO-SANITIZE-WITH-ATTR-NEXT:    store i32 [[CONV]], ptr [[ARRAYIDX]], align 4, !tbaa [[TBAA2]]
@@ -539,10 +537,9 @@ size_t test5_bdos(struct anon_struct *p) {
 // SANITIZE-WITH-ATTR:       cont3:
 // SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 16
 // SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [0 x i32], ptr [[TMP1]], i64 0, i64 [[IDXPROM]]
-// SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i64 [[DOT_COUNTED_BY_LOAD]], 0
-// SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD_TR:%.*]] = trunc i64 [[DOT_COUNTED_BY_LOAD]] to i32
-// SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD_TR]], 2
-// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP2]]
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = tail call i64 @llvm.smax.i64(i64 [[DOT_COUNTED_BY_LOAD]], i64 0)
+// SANITIZE-WITH-ATTR-NEXT:    [[DOTTR:%.*]] = trunc i64 [[TMP2]] to i32
+// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[DOTTR]], 2
 // SANITIZE-WITH-ATTR-NEXT:    store i32 [[CONV]], ptr [[ARRAYIDX]], align 4, !tbaa [[TBAA4]]
 // SANITIZE-WITH-ATTR-NEXT:    ret void
 //
@@ -551,10 +548,9 @@ size_t test5_bdos(struct anon_struct *p) {
 // NO-SANITIZE-WITH-ATTR-NEXT:  entry:
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 8
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i64, ptr [[DOT_COUNTED_BY_GEP]], align 4
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i64 [[DOT_COUNTED_BY_LOAD]], 0
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD_TR:%.*]] = trunc i64 [[DOT_COUNTED_BY_LOAD]] to i32
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD_TR]], 2
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP0]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = tail call i64 @llvm.smax.i64(i64 [[DOT_COUNTED_BY_LOAD]], i64 0)
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTTR:%.*]] = trunc i64 [[TMP0]] to i32
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[DOTTR]], 2
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = getelementptr inbounds nuw i8, ptr [[P]], i64 16
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[IDXPROM:%.*]] = sext i32 [[INDEX]] to i64
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [0 x i32], ptr [[TMP1]], i64 0, i64 [[IDXPROM]]
@@ -588,19 +584,17 @@ void test6(struct anon_struct *p, int index) {
 // SANITIZE-WITH-ATTR-NEXT:  entry:
 // SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 8
 // SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i64, ptr [[DOT_COUNTED_BY_GEP]], align 4
-// SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = shl nuw i64 [[DOT_COUNTED_BY_LOAD]], 2
-// SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i64 [[DOT_COUNTED_BY_LOAD]], 0
-// SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = select i1 [[DOTINV]], i64 0, i64 [[TMP0]]
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = tail call i64 @llvm.smax.i64(i64 [[DOT_COUNTED_BY_LOAD]], i64 0)
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = shl i64 [[TMP0]], 2
 // SANITIZE-WITH-ATTR-NEXT:    ret i64 [[TMP1]]
 //
 // NO-SANITIZE-WITH-ATTR-LABEL: define dso_local range(i64 0, -3) i64 @test6_bdos(
 // NO-SANITIZE-WITH-ATTR-SAME: ptr nocapture noundef readonly [[P:%.*]]) local_unnamed_addr #[[ATTR2]] {
 // NO-SANITIZE-WITH-ATTR-NEXT:  entry:
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 8
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i64, ptr [[DOT_COUNTED_BY_GEP]], align 4
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = shl nuw i64 [[DOT_COUNTED_BY_LOAD]], 2
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i64 [[DOT_COUNTED_BY_LOAD]], 0
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = select i1 [[DOTINV]], i64 0, i64 [[TMP0]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = tail call i64 @llvm.smax.i64(i64 [[DOT_COUNTED_BY_LOAD]], i64 0)
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = shl i64 [[TMP0]], 2
 // NO-SANITIZE-WITH-ATTR-NEXT:    ret i64 [[TMP1]]
 //
 // SANITIZE-WITHOUT-ATTR-LABEL: define dso_local i64 @test6_bdos(
@@ -1740,9 +1734,8 @@ struct annotated_struct_array {
 // SANITIZE-WITH-ATTR:       cont20:
 // SANITIZE-WITH-ATTR-NEXT:    [[ARRAY:%.*]] = getelementptr inbounds nuw i8, ptr [[TMP2]], i64 12
 // SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX18:%.*]] = getelementptr inbounds [0 x i32], ptr [[ARRAY]], i64 0, i64 [[IDXPROM15]]
-// SANITIZE-WITH-ATTR-NEXT:    [[TMP5:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD]], 2
-// SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i32 [[DOT_COUNTED_BY_LOAD]], 0
-// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP5]]
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP5:%.*]] = tail call i32 @llvm.smax.i32(i32 [[DOT_COUNTED_BY_LOAD]], i32 0)
+// SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[TMP5]], 2
 // SANITIZE-WITH-ATTR-NEXT:    store i32 [[CONV]], ptr [[ARRAYIDX18]], align 4, !tbaa [[TBAA4]]
 // SANITIZE-WITH-ATTR-NEXT:    ret void
 //
@@ -1754,9 +1747,8 @@ struct annotated_struct_array {
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[ARRAYIDX]], align 8, !tbaa [[TBAA11]]
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i64 8
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i32, ptr [[DOT_COUNTED_BY_GEP]], align 4
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = shl i32 [[DOT_COUNTED_BY_LOAD]], 2
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i32 [[DOT_COUNTED_BY_LOAD]], 0
-// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i32 0, i32 [[TMP1]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = tail call i32 @llvm.smax.i32(i32 [[DOT_COUNTED_BY_LOAD]], i32 0)
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = shl i32 [[TMP1]], 2
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAY:%.*]] = getelementptr inbounds nuw i8, ptr [[TMP0]], i64 12
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[IDXPROM4:%.*]] = sext i32 [[IDX2]] to i64
 // NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX5:%.*]] = getelementptr inbounds [0 x i32], ptr [[ARRAY]], i64 0, i64 [[IDXPROM4]]

llvm/include/llvm/Analysis/ValueTracking.h

@@ -1178,10 +1178,20 @@ SelectPatternResult matchDecomposedSelectPattern(
     CmpInst *CmpI, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS,
     Instruction::CastOps *CastOp = nullptr, unsigned Depth = 0);
 
+/// Determine the pattern for predicate `X Pred Y ? X : Y`.
+SelectPatternResult
+getSelectPattern(CmpInst::Predicate Pred,
+                 SelectPatternNaNBehavior NaNBehavior = SPNB_NA,
+                 bool Ordered = false);
+
 /// Return the canonical comparison predicate for the specified
 /// minimum/maximum flavor.
 CmpInst::Predicate getMinMaxPred(SelectPatternFlavor SPF, bool Ordered = false);
 
+/// Convert given `SPF` to equivalent min/max intrinsic.
+/// Caller must ensure `SPF` is an integer min or max pattern.
+Intrinsic::ID getMinMaxIntrinsic(SelectPatternFlavor SPF);
+
 /// Return the inverse minimum/maximum flavor of the specified flavor.
 /// For example, signed minimum is the inverse of signed maximum.
 SelectPatternFlavor getInverseMinMaxFlavor(SelectPatternFlavor SPF);

llvm/lib/Analysis/ValueTracking.cpp

@@ -8589,6 +8589,37 @@ bool llvm::isKnownInversion(const Value *X, const Value *Y) {
   return CR1.inverse() == CR2;
 }
 
+SelectPatternResult llvm::getSelectPattern(CmpInst::Predicate Pred,
+                                           SelectPatternNaNBehavior NaNBehavior,
+                                           bool Ordered) {
+  switch (Pred) {
+  default:
+    return {SPF_UNKNOWN, SPNB_NA, false}; // Equality.
+  case ICmpInst::ICMP_UGT:
+  case ICmpInst::ICMP_UGE:
+    return {SPF_UMAX, SPNB_NA, false};
+  case ICmpInst::ICMP_SGT:
+  case ICmpInst::ICMP_SGE:
+    return {SPF_SMAX, SPNB_NA, false};
+  case ICmpInst::ICMP_ULT:
+  case ICmpInst::ICMP_ULE:
+    return {SPF_UMIN, SPNB_NA, false};
+  case ICmpInst::ICMP_SLT:
+  case ICmpInst::ICMP_SLE:
+    return {SPF_SMIN, SPNB_NA, false};
+  case FCmpInst::FCMP_UGT:
+  case FCmpInst::FCMP_UGE:
+  case FCmpInst::FCMP_OGT:
+  case FCmpInst::FCMP_OGE:
+    return {SPF_FMAXNUM, NaNBehavior, Ordered};
+  case FCmpInst::FCMP_ULT:
+  case FCmpInst::FCMP_ULE:
+  case FCmpInst::FCMP_OLT:
+  case FCmpInst::FCMP_OLE:
+    return {SPF_FMINNUM, NaNBehavior, Ordered};
+  }
+}
+
 static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred,
                                               FastMathFlags FMF,
                                               Value *CmpLHS, Value *CmpRHS,
@@ -8696,27 +8727,8 @@ static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred,
   }
 
   // ([if]cmp X, Y) ? X : Y
-  if (TrueVal == CmpLHS && FalseVal == CmpRHS) {
-    switch (Pred) {
-    default: return {SPF_UNKNOWN, SPNB_NA, false}; // Equality.
-    case ICmpInst::ICMP_UGT:
-    case ICmpInst::ICMP_UGE: return {SPF_UMAX, SPNB_NA, false};
-    case ICmpInst::ICMP_SGT:
-    case ICmpInst::ICMP_SGE: return {SPF_SMAX, SPNB_NA, false};
-    case ICmpInst::ICMP_ULT:
-    case ICmpInst::ICMP_ULE: return {SPF_UMIN, SPNB_NA, false};
-    case ICmpInst::ICMP_SLT:
-    case ICmpInst::ICMP_SLE: return {SPF_SMIN, SPNB_NA, false};
-    case FCmpInst::FCMP_UGT:
-    case FCmpInst::FCMP_UGE:
-    case FCmpInst::FCMP_OGT:
-    case FCmpInst::FCMP_OGE: return {SPF_FMAXNUM, NaNBehavior, Ordered};
-    case FCmpInst::FCMP_ULT:
-    case FCmpInst::FCMP_ULE:
-    case FCmpInst::FCMP_OLT:
-    case FCmpInst::FCMP_OLE: return {SPF_FMINNUM, NaNBehavior, Ordered};
-    }
-  }
+  if (TrueVal == CmpLHS && FalseVal == CmpRHS)
+    return getSelectPattern(Pred, NaNBehavior, Ordered);
 
   if (isKnownNegation(TrueVal, FalseVal)) {
     // Sign-extending LHS does not change its sign, so TrueVal/FalseVal can
@@ -8960,6 +8972,21 @@ CmpInst::Predicate llvm::getMinMaxPred(SelectPatternFlavor SPF, bool Ordered) {
   llvm_unreachable("unhandled!");
 }
 
+Intrinsic::ID llvm::getMinMaxIntrinsic(SelectPatternFlavor SPF) {
+  switch (SPF) {
+  case SelectPatternFlavor::SPF_UMIN:
+    return Intrinsic::umin;
+  case SelectPatternFlavor::SPF_UMAX:
+    return Intrinsic::umax;
+  case SelectPatternFlavor::SPF_SMIN:
+    return Intrinsic::smin;
+  case SelectPatternFlavor::SPF_SMAX:
+    return Intrinsic::smax;
+  default:
+    llvm_unreachable("Unexpected SPF");
+  }
+}
+
 SelectPatternFlavor llvm::getInverseMinMaxFlavor(SelectPatternFlavor SPF) {
   if (SPF == SPF_SMIN) return SPF_SMAX;
   if (SPF == SPF_UMIN) return SPF_UMAX;

llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp

@@ -1257,23 +1257,7 @@ static Value *canonicalizeSPF(ICmpInst &Cmp, Value *TrueVal, Value *FalseVal,
   }
 
   if (SelectPatternResult::isMinOrMax(SPF)) {
-    Intrinsic::ID IntrinsicID;
-    switch (SPF) {
-    case SelectPatternFlavor::SPF_UMIN:
-      IntrinsicID = Intrinsic::umin;
-      break;
-    case SelectPatternFlavor::SPF_UMAX:
-      IntrinsicID = Intrinsic::umax;
-      break;
-    case SelectPatternFlavor::SPF_SMIN:
-      IntrinsicID = Intrinsic::smin;
-      break;
-    case SelectPatternFlavor::SPF_SMAX:
-      IntrinsicID = Intrinsic::smax;
-      break;
-    default:
-      llvm_unreachable("Unexpected SPF");
-    }
+    Intrinsic::ID IntrinsicID = getMinMaxIntrinsic(SPF);
     return IC.Builder.CreateBinaryIntrinsic(IntrinsicID, LHS, RHS);
   }
 
@@ -1898,6 +1882,63 @@ static Instruction *foldSelectICmpEq(SelectInst &SI, ICmpInst *ICI,
   return nullptr;
 }
 
+/// Fold `X Pred C1 ? X BOp C2 : C1 BOp C2` to `min/max(X, C1) BOp C2`.
+/// This allows for better canonicalization.
+static Value *foldSelectWithConstOpToBinOp(ICmpInst *Cmp, Value *TrueVal,
+                                           Value *FalseVal,
+                                           IRBuilderBase &Builder) {
+  BinaryOperator *BOp;
+  Constant *C1, *C2, *C3;
+  Value *X;
+  ICmpInst::Predicate Predicate;
+
+  if (!match(Cmp, m_ICmp(Predicate, m_Value(X), m_Constant(C1))))
+    return nullptr;
+
+  if (!ICmpInst::isRelational(Predicate))
+    return nullptr;
+
+  if (match(TrueVal, m_Constant())) {
+    std::swap(FalseVal, TrueVal);
+    Predicate = ICmpInst::getInversePredicate(Predicate);
+  }
+
+  if (!match(TrueVal, m_BinOp(BOp)) || !match(FalseVal, m_Constant(C3)))
+    return nullptr;
+
+  unsigned Opcode = BOp->getOpcode();
+
+  // This fold causes some regressions and is primarily intended for
+  // add and sub. So we early exit for div and rem to minimize the
+  // regressions.
+  if (Instruction::isIntDivRem(Opcode))
+    return nullptr;
+
+  if (!match(BOp, m_OneUse(m_BinOp(m_Specific(X), m_Constant(C2)))))
+    return nullptr;
+
+  Value *RHS;
+  SelectPatternFlavor SPF;
+  const DataLayout &DL = BOp->getDataLayout();
+  auto Flipped =
+      InstCombiner::getFlippedStrictnessPredicateAndConstant(Predicate, C1);
+
+  if (C3 == ConstantFoldBinaryOpOperands(Opcode, C1, C2, DL)) {
+    SPF = getSelectPattern(Predicate).Flavor;
+    RHS = C1;
+  } else if (Flipped && C3 == ConstantFoldBinaryOpOperands(
+                                  Opcode, Flipped->second, C2, DL)) {
+    SPF = getSelectPattern(Flipped->first).Flavor;
+    RHS = Flipped->second;
+  } else {
+    return nullptr;
+  }
+
+  Intrinsic::ID IntrinsicID = getMinMaxIntrinsic(SPF);
+  Value *Intrinsic = Builder.CreateBinaryIntrinsic(IntrinsicID, X, RHS);
+  return Builder.CreateBinOp(BOp->getOpcode(), Intrinsic, C2);
+}
+
 /// Visit a SelectInst that has an ICmpInst as its first operand.
 Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
                                                       ICmpInst *ICI) {
@@ -1987,6 +2028,9 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
   if (Value *V = foldAbsDiff(ICI, TrueVal, FalseVal, Builder))
     return replaceInstUsesWith(SI, V);
 
+  if (Value *V = foldSelectWithConstOpToBinOp(ICI, TrueVal, FalseVal, Builder))
+    return replaceInstUsesWith(SI, V);
+
   return Changed ? &SI : nullptr;
 }