VT: teach implied-cond about samesign

llvm/include/llvm/IR/InstrTypes.h

@@ -967,14 +967,6 @@ class CmpInst : public Instruction {
   /// Determine if the predicate is false when comparing a value with itself.
   static bool isFalseWhenEqual(Predicate predicate);
 
-  /// Determine if Pred1 implies Pred2 is true when two compares have matching
-  /// operands.
-  static bool isImpliedTrueByMatchingCmp(Predicate Pred1, Predicate Pred2);
-
-  /// Determine if Pred1 implies Pred2 is false when two compares have matching
-  /// operands.
-  static bool isImpliedFalseByMatchingCmp(Predicate Pred1, Predicate Pred2);
-
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Instruction *I) {
     return I->getOpcode() == Instruction::ICmp ||

llvm/include/llvm/IR/Instructions.h

@@ -1266,6 +1266,16 @@ class ICmpInst: public CmpInst {
     return getFlippedSignednessPredicate(getPredicate());
   }
 
+  /// Determine if Pred1 implies Pred2 is true when two compares have matching
+  /// operands.
+  static bool isImpliedTrueByMatchingCmp(CmpPredicate Pred1,
+                                         CmpPredicate Pred2);
+
+  /// Determine if Pred1 implies Pred2 is false when two compares have matching
+  /// operands.
+  static bool isImpliedFalseByMatchingCmp(CmpPredicate Pred1,
+                                          CmpPredicate Pred2);
+
   void setSameSign(bool B = true) {
     SubclassOptionalData = (SubclassOptionalData & ~SameSign) | (B * SameSign);
   }

llvm/include/llvm/SandboxIR/Instruction.h

@@ -2511,13 +2511,6 @@ class CmpInst : public SingleLLVMInstructionImpl<llvm::CmpInst> {
   WRAP_STATIC_PREDICATE(isOrdered);
   WRAP_STATIC_PREDICATE(isUnordered);
 
-  static bool isImpliedTrueByMatchingCmp(Predicate Pred1, Predicate Pred2) {
-    return llvm::CmpInst::isImpliedTrueByMatchingCmp(Pred1, Pred2);
-  }
-  static bool isImpliedFalseByMatchingCmp(Predicate Pred1, Predicate Pred2) {
-    return llvm::CmpInst::isImpliedFalseByMatchingCmp(Pred1, Pred2);
-  }
-
   /// Method for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Value *From) {
     return From->getSubclassID() == ClassID::ICmp ||
@@ -2554,6 +2547,15 @@ class ICmpInst : public CmpInst {
   WRAP_STATIC_PREDICATE(isGE);
   WRAP_STATIC_PREDICATE(isLE);
 
+  static bool isImpliedTrueByMatchingCmp(CmpPredicate Pred1,
+                                         CmpPredicate Pred2) {
+    return llvm::ICmpInst::isImpliedTrueByMatchingCmp(Pred1, Pred2);
+  }
+  static bool isImpliedFalseByMatchingCmp(CmpPredicate Pred1,
+                                          CmpPredicate Pred2) {
+    return llvm::ICmpInst::isImpliedFalseByMatchingCmp(Pred1, Pred2);
+  }
+
   static auto predicates() { return llvm::ICmpInst::predicates(); }
   static bool compare(const APInt &LHS, const APInt &RHS,
                       ICmpInst::Predicate Pred) {

llvm/lib/Analysis/ValueTracking.cpp

@@ -9141,7 +9141,7 @@ bool llvm::matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P,
 }
 
 /// Return true if "icmp Pred LHS RHS" is always true.
-static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
+static bool isTruePredicate(CmpPredicate Pred, const Value *LHS,
                             const Value *RHS) {
   if (ICmpInst::isTrueWhenEqual(Pred) && LHS == RHS)
     return true;
@@ -9223,8 +9223,8 @@ static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
 /// Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred
 /// ALHS ARHS" is true.  Otherwise, return std::nullopt.
 static std::optional<bool>
-isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
-                      const Value *ARHS, const Value *BLHS, const Value *BRHS) {
+isImpliedCondOperands(CmpPredicate Pred, const Value *ALHS, const Value *ARHS,
+                      const Value *BLHS, const Value *BRHS) {
   switch (Pred) {
   default:
     return std::nullopt;
@@ -9262,12 +9262,11 @@ isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
 /// Return true if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is true.
 /// Return false if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is false.
 /// Otherwise, return std::nullopt if we can't infer anything.
-static std::optional<bool>
-isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
-                              CmpInst::Predicate RPred) {
-  if (CmpInst::isImpliedTrueByMatchingCmp(LPred, RPred))
+static std::optional<bool> isImpliedCondMatchingOperands(CmpPredicate LPred,
+                                                         CmpPredicate RPred) {
+  if (ICmpInst::isImpliedTrueByMatchingCmp(LPred, RPred))
     return true;
-  if (CmpInst::isImpliedFalseByMatchingCmp(LPred, RPred))
+  if (ICmpInst::isImpliedFalseByMatchingCmp(LPred, RPred))
     return false;
 
   return std::nullopt;
@@ -9276,53 +9275,66 @@ isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
 /// Return true if "icmp LPred X, LCR" implies "icmp RPred X, RCR" is true.
 /// Return false if "icmp LPred X, LCR" implies "icmp RPred X, RCR" is false.
 /// Otherwise, return std::nullopt if we can't infer anything.
-static std::optional<bool> isImpliedCondCommonOperandWithCR(
-    CmpInst::Predicate LPred, const ConstantRange &LCR,
-    CmpInst::Predicate RPred, const ConstantRange &RCR) {
-  ConstantRange DomCR = ConstantRange::makeAllowedICmpRegion(LPred, LCR);
-  // If all true values for lhs and true for rhs, lhs implies rhs
-  if (DomCR.icmp(RPred, RCR))
-    return true;
+static std::optional<bool>
+isImpliedCondCommonOperandWithCR(CmpPredicate LPred, const ConstantRange &LCR,
+                                 CmpPredicate RPred, const ConstantRange &RCR) {
+  auto CRImpliesPred = [&](ConstantRange CR,
+                           CmpInst::Predicate Pred) -> std::optional<bool> {
+    // If all true values for lhs and true for rhs, lhs implies rhs
+    if (CR.icmp(Pred, RCR))
+      return true;
 
-  // If there is no overlap, lhs implies not rhs
-  if (DomCR.icmp(CmpInst::getInversePredicate(RPred), RCR))
-    return false;
+    // If there is no overlap, lhs implies not rhs
+    if (CR.icmp(CmpInst::getInversePredicate(Pred), RCR))
+      return false;
+
+    return std::nullopt;
+  };
+  if (auto Res = CRImpliesPred(ConstantRange::makeAllowedICmpRegion(LPred, LCR),
+                               RPred))
+    return Res;
+  if (LPred.hasSameSign() ^ RPred.hasSameSign()) {
+    LPred = LPred.hasSameSign() ? ICmpInst::getFlippedSignednessPredicate(LPred)
+                                : static_cast<CmpInst::Predicate>(LPred);
+    RPred = RPred.hasSameSign() ? ICmpInst::getFlippedSignednessPredicate(RPred)
+                                : static_cast<CmpInst::Predicate>(RPred);
+    return CRImpliesPred(ConstantRange::makeAllowedICmpRegion(LPred, LCR),
+                         RPred);
+  }
   return std::nullopt;
 }
 
 /// Return true if LHS implies RHS (expanded to its components as "R0 RPred R1")
 /// is true.  Return false if LHS implies RHS is false. Otherwise, return
 /// std::nullopt if we can't infer anything.
-static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
-                                              CmpInst::Predicate RPred,
-                                              const Value *R0, const Value *R1,
-                                              const DataLayout &DL,
-                                              bool LHSIsTrue) {
+static std::optional<bool>
+isImpliedCondICmps(const ICmpInst *LHS, CmpPredicate RPred, const Value *R0,
+                   const Value *R1, const DataLayout &DL, bool LHSIsTrue) {
   Value *L0 = LHS->getOperand(0);
   Value *L1 = LHS->getOperand(1);
 
   // The rest of the logic assumes the LHS condition is true.  If that's not the
   // case, invert the predicate to make it so.
-  CmpInst::Predicate LPred =
-      LHSIsTrue ? LHS->getPredicate() : LHS->getInversePredicate();
+  CmpPredicate LPred =
+      LHSIsTrue ? LHS->getCmpPredicate() : LHS->getInverseCmpPredicate();
 
   // We can have non-canonical operands, so try to normalize any common operand
   // to L0/R0.
   if (L0 == R1) {
     std::swap(R0, R1);
-    RPred = ICmpInst::getSwappedPredicate(RPred);
+    RPred = ICmpInst::getSwappedCmpPredicate(RPred);
   }
   if (R0 == L1) {
     std::swap(L0, L1);
-    LPred = ICmpInst::getSwappedPredicate(LPred);
+    LPred = ICmpInst::getSwappedCmpPredicate(LPred);
   }
   if (L1 == R1) {
     // If we have L0 == R0 and L1 == R1, then make L1/R1 the constants.
     if (L0 != R0 || match(L0, m_ImmConstant())) {
       std::swap(L0, L1);
-      LPred = ICmpInst::getSwappedPredicate(LPred);
+      LPred = ICmpInst::getSwappedCmpPredicate(LPred);
       std::swap(R0, R1);
-      RPred = ICmpInst::getSwappedPredicate(RPred);
+      RPred = ICmpInst::getSwappedCmpPredicate(RPred);
     }
   }
 
@@ -9358,7 +9370,8 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
   // must be positive if X >= Y and no overflow".
   // Take SGT as an example:  L0:x > L1:y and C >= 0
   //                      ==> R0:(x -nsw y) < R1:(-C) is false
-  if ((LPred == ICmpInst::ICMP_SGT || LPred == ICmpInst::ICMP_SGE) &&
+  if ((ICmpInst::isSigned(LPred) || LPred.hasSameSign()) &&
+      (ICmpInst::isGE(LPred) || ICmpInst::isGT(LPred)) &&
       match(R0, m_NSWSub(m_Specific(L0), m_Specific(L1)))) {
     if (match(R1, m_NonPositive()) &&
         isImpliedCondMatchingOperands(LPred, RPred) == false)
@@ -9367,7 +9380,8 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
 
   // Take SLT as an example:  L0:x < L1:y and C <= 0
   //                      ==> R0:(x -nsw y) < R1:(-C) is true
-  if ((LPred == ICmpInst::ICMP_SLT || LPred == ICmpInst::ICMP_SLE) &&
+  if ((ICmpInst::isSigned(LPred) || LPred.hasSameSign()) &&
+      (ICmpInst::isLE(LPred) || ICmpInst::isLT(LPred)) &&
       match(R0, m_NSWSub(m_Specific(L0), m_Specific(L1)))) {
     if (match(R1, m_NonNegative()) &&
         isImpliedCondMatchingOperands(LPred, RPred) == true)
@@ -9381,8 +9395,8 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
       match(L0, m_c_Add(m_Specific(L1), m_Specific(R1))))
     return CmpPredicate::getMatching(LPred, RPred).has_value();
 
-  if (LPred == RPred)
-    return isImpliedCondOperands(LPred, L0, L1, R0, R1);
+  if (auto P = CmpPredicate::getMatching(LPred, RPred))
+    return isImpliedCondOperands(*P, L0, L1, R0, R1);
 
   return std::nullopt;
 }

llvm/lib/IR/Instructions.cpp

@@ -3886,12 +3886,18 @@ bool CmpInst::isFalseWhenEqual(Predicate predicate) {
   }
 }
 
-bool CmpInst::isImpliedTrueByMatchingCmp(Predicate Pred1, Predicate Pred2) {
+bool ICmpInst::isImpliedTrueByMatchingCmp(CmpPredicate Pred1,
+                                          CmpPredicate Pred2) {
   // If the predicates match, then we know the first condition implies the
   // second is true.
-  if (Pred1 == Pred2)
+  if (CmpPredicate::getMatching(Pred1, Pred2))
     return true;
 
+  if (Pred1.hasSameSign() && CmpInst::isSigned(Pred2))
+    Pred1 = ICmpInst::getFlippedSignednessPredicate(Pred1);
+  else if (Pred2.hasSameSign() && CmpInst::isSigned(Pred1))
+    Pred2 = ICmpInst::getFlippedSignednessPredicate(Pred2);
+
   switch (Pred1) {
   default:
     break;
@@ -3911,7 +3917,8 @@ bool CmpInst::isImpliedTrueByMatchingCmp(Predicate Pred1, Predicate Pred2) {
   return false;
 }
 
-bool CmpInst::isImpliedFalseByMatchingCmp(Predicate Pred1, Predicate Pred2) {
+bool ICmpInst::isImpliedFalseByMatchingCmp(CmpPredicate Pred1,
+                                           CmpPredicate Pred2) {
   return isImpliedTrueByMatchingCmp(Pred1, getInversePredicate(Pred2));
 }
 

llvm/lib/Transforms/Scalar/NewGVN.cpp

@@ -1964,15 +1964,15 @@ NewGVN::ExprResult NewGVN::performSymbolicCmpEvaluation(Instruction *I) const {
         if (PBranch->TrueEdge) {
           // If we know the previous predicate is true and we are in the true
           // edge then we may be implied true or false.
-          if (CmpInst::isImpliedTrueByMatchingCmp(BranchPredicate,
-                                                  OurPredicate)) {
+          if (ICmpInst::isImpliedTrueByMatchingCmp(BranchPredicate,
+                                                   OurPredicate)) {
             return ExprResult::some(
                 createConstantExpression(ConstantInt::getTrue(CI->getType())),
                 PI);
           }
 
-          if (CmpInst::isImpliedFalseByMatchingCmp(BranchPredicate,
-                                                   OurPredicate)) {
+          if (ICmpInst::isImpliedFalseByMatchingCmp(BranchPredicate,
+                                                    OurPredicate)) {
             return ExprResult::some(
                 createConstantExpression(ConstantInt::getFalse(CI->getType())),
                 PI);