[llvm] a5a6960 - [NFCI][IR] MinMaxIntrinsic: add some more helper methods, and use them

Roman Lebedev via llvm-commits llvm-commits at lists.llvm.org
Fri Jan 7 02:02:31 PST 2022


Author: Roman Lebedev
Date: 2022-01-07T13:02:11+03:00
New Revision: a5a6960d1c93f1da1447ba956811928b2154c8ef

URL: https://github.com/llvm/llvm-project/commit/a5a6960d1c93f1da1447ba956811928b2154c8ef
DIFF: https://github.com/llvm/llvm-project/commit/a5a6960d1c93f1da1447ba956811928b2154c8ef.diff

LOG: [NFCI][IR] MinMaxIntrinsic: add some more helper methods, and use them

Added: 
    

Modified: 
    llvm/include/llvm/IR/IntrinsicInst.h
    llvm/lib/Analysis/ConstantFolding.cpp
    llvm/lib/Analysis/InstructionSimplify.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/IntrinsicInst.h b/llvm/include/llvm/IR/IntrinsicInst.h
index 647a912b72f64..5906b1aaf2ceb 100644
--- a/llvm/include/llvm/IR/IntrinsicInst.h
+++ b/llvm/include/llvm/IR/IntrinsicInst.h
@@ -530,8 +530,8 @@ class MinMaxIntrinsic : public IntrinsicInst {
   Value *getRHS() const { return const_cast<Value *>(getArgOperand(1)); }
 
   /// Returns the comparison predicate underlying the intrinsic.
-  ICmpInst::Predicate getPredicate() const {
-    switch (getIntrinsicID()) {
+  static ICmpInst::Predicate getPredicate(Intrinsic::ID ID) {
+    switch (ID) {
     case Intrinsic::umin:
       return ICmpInst::Predicate::ICMP_ULT;
     case Intrinsic::umax:
@@ -545,8 +545,58 @@ class MinMaxIntrinsic : public IntrinsicInst {
     }
   }
 
+  /// Returns the comparison predicate underlying the intrinsic.
+  ICmpInst::Predicate getPredicate() const {
+    return getPredicate(getIntrinsicID());
+  }
+
   /// Whether the intrinsic is signed or unsigned.
-  bool isSigned() const { return ICmpInst::isSigned(getPredicate()); };
+  static bool isSigned(Intrinsic::ID ID) {
+    return ICmpInst::isSigned(getPredicate(ID));
+  };
+
+  /// Whether the intrinsic is signed or unsigned.
+  bool isSigned() const { return isSigned(getIntrinsicID()); };
+
+  /// Min/max intrinsics are monotonic, they operate on a fixed-bitwidth values,
+  /// so there is a certain threshold value, upon reaching which,
+  /// their value can no longer change. Return said threshold.
+  static APInt getSaturationPoint(Intrinsic::ID ID, unsigned numBits) {
+    switch (ID) {
+    case Intrinsic::umin:
+      return APInt::getMinValue(numBits);
+    case Intrinsic::umax:
+      return APInt::getMaxValue(numBits);
+    case Intrinsic::smin:
+      return APInt::getSignedMinValue(numBits);
+    case Intrinsic::smax:
+      return APInt::getSignedMaxValue(numBits);
+    default:
+      llvm_unreachable("Invalid intrinsic");
+    }
+  }
+
+  /// Min/max intrinsics are monotonic, they operate on a fixed-bitwidth values,
+  /// so there is a certain threshold value, upon reaching which,
+  /// their value can no longer change. Return said threshold.
+  APInt getSaturationPoint(unsigned numBits) const {
+    return getSaturationPoint(getIntrinsicID(), numBits);
+  }
+
+  /// Min/max intrinsics are monotonic, they operate on a fixed-bitwidth values,
+  /// so there is a certain threshold value, upon reaching which,
+  /// their value can no longer change. Return said threshold.
+  static Constant *getSaturationPoint(Intrinsic::ID ID, Type *Ty) {
+    return Constant::getIntegerValue(
+        Ty, getSaturationPoint(ID, Ty->getScalarSizeInBits()));
+  }
+
+  /// Min/max intrinsics are monotonic, they operate on a fixed-bitwidth values,
+  /// so there is a certain threshold value, upon reaching which,
+  /// their value can no longer change. Return said threshold.
+  Constant *getSaturationPoint(Type *Ty) const {
+    return getSaturationPoint(getIntrinsicID(), Ty);
+  }
 };
 
 /// This class represents an intrinsic that is based on a binary operation.

diff  --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index a373e69c35559..d25694b0c0eda 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -2467,36 +2467,21 @@ static Constant *ConstantFoldScalarCall2(StringRef Name,
         !getConstIntOrUndef(Operands[1], C1))
       return nullptr;
 
-    unsigned BitWidth = Ty->getScalarSizeInBits();
     switch (IntrinsicID) {
     default: break;
     case Intrinsic::smax:
-      if (!C0 && !C1)
-        return UndefValue::get(Ty);
-      if (!C0 || !C1)
-        return ConstantInt::get(Ty, APInt::getSignedMaxValue(BitWidth));
-      return ConstantInt::get(Ty, C0->sgt(*C1) ? *C0 : *C1);
-
     case Intrinsic::smin:
-      if (!C0 && !C1)
-        return UndefValue::get(Ty);
-      if (!C0 || !C1)
-        return ConstantInt::get(Ty, APInt::getSignedMinValue(BitWidth));
-      return ConstantInt::get(Ty, C0->slt(*C1) ? *C0 : *C1);
-
     case Intrinsic::umax:
-      if (!C0 && !C1)
-        return UndefValue::get(Ty);
-      if (!C0 || !C1)
-        return ConstantInt::get(Ty, APInt::getMaxValue(BitWidth));
-      return ConstantInt::get(Ty, C0->ugt(*C1) ? *C0 : *C1);
-
     case Intrinsic::umin:
       if (!C0 && !C1)
         return UndefValue::get(Ty);
       if (!C0 || !C1)
-        return ConstantInt::get(Ty, APInt::getMinValue(BitWidth));
-      return ConstantInt::get(Ty, C0->ult(*C1) ? *C0 : *C1);
+        return MinMaxIntrinsic::getSaturationPoint(IntrinsicID, Ty);
+      return ConstantInt::get(
+          Ty, ICmpInst::compare(*C0, *C1,
+                                MinMaxIntrinsic::getPredicate(IntrinsicID))
+                  ? *C0
+                  : *C1);
 
     case Intrinsic::usub_with_overflow:
     case Intrinsic::ssub_with_overflow:

diff  --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 15800898a15a1..8bdcb70a41708 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -5615,26 +5615,6 @@ static Value *simplifyUnaryIntrinsic(Function *F, Value *Op0,
   return nullptr;
 }
 
-static APInt getMaxMinLimit(Intrinsic::ID IID, unsigned BitWidth) {
-  switch (IID) {
-  case Intrinsic::smax: return APInt::getSignedMaxValue(BitWidth);
-  case Intrinsic::smin: return APInt::getSignedMinValue(BitWidth);
-  case Intrinsic::umax: return APInt::getMaxValue(BitWidth);
-  case Intrinsic::umin: return APInt::getMinValue(BitWidth);
-  default: llvm_unreachable("Unexpected intrinsic");
-  }
-}
-
-static ICmpInst::Predicate getMaxMinPredicate(Intrinsic::ID IID) {
-  switch (IID) {
-  case Intrinsic::smax: return ICmpInst::ICMP_SGE;
-  case Intrinsic::smin: return ICmpInst::ICMP_SLE;
-  case Intrinsic::umax: return ICmpInst::ICMP_UGE;
-  case Intrinsic::umin: return ICmpInst::ICMP_ULE;
-  default: llvm_unreachable("Unexpected intrinsic");
-  }
-}
-
 /// Given a min/max intrinsic, see if it can be removed based on having an
 /// operand that is another min/max intrinsic with shared operand(s). The caller
 /// is expected to swap the operand arguments to handle commutation.
@@ -5702,19 +5682,21 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
 
     // Assume undef is the limit value.
     if (Q.isUndefValue(Op1))
-      return ConstantInt::get(ReturnType, getMaxMinLimit(IID, BitWidth));
+      return ConstantInt::get(
+          ReturnType, MinMaxIntrinsic::getSaturationPoint(IID, BitWidth));
 
     const APInt *C;
     if (match(Op1, m_APIntAllowUndef(C))) {
       // Clamp to limit value. For example:
       // umax(i8 %x, i8 255) --> 255
-      if (*C == getMaxMinLimit(IID, BitWidth))
+      if (*C == MinMaxIntrinsic::getSaturationPoint(IID, BitWidth))
         return ConstantInt::get(ReturnType, *C);
 
       // If the constant op is the opposite of the limit value, the other must
       // be larger/smaller or equal. For example:
       // umin(i8 %x, i8 255) --> %x
-      if (*C == getMaxMinLimit(getInverseMinMaxIntrinsic(IID), BitWidth))
+      if (*C == MinMaxIntrinsic::getSaturationPoint(
+                    getInverseMinMaxIntrinsic(IID), BitWidth))
         return Op0;
 
       // Remove nested call if constant operands allow it. Example:
@@ -5725,10 +5707,9 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
         Value *M00 = MinMax0->getOperand(0), *M01 = MinMax0->getOperand(1);
         const APInt *InnerC;
         if ((match(M00, m_APInt(InnerC)) || match(M01, m_APInt(InnerC))) &&
-            ((IID == Intrinsic::smax && InnerC->sge(*C)) ||
-             (IID == Intrinsic::smin && InnerC->sle(*C)) ||
-             (IID == Intrinsic::umax && InnerC->uge(*C)) ||
-             (IID == Intrinsic::umin && InnerC->ule(*C))))
+            ICmpInst::compare(*InnerC, *C,
+                              ICmpInst::getNonStrictPredicate(
+                                  MinMaxIntrinsic::getPredicate(IID))))
           return Op0;
       }
     }
@@ -5738,7 +5719,8 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
     if (Value *V = foldMinMaxSharedOp(IID, Op1, Op0))
       return V;
 
-    ICmpInst::Predicate Pred = getMaxMinPredicate(IID);
+    ICmpInst::Predicate Pred =
+        ICmpInst::getNonStrictPredicate(MinMaxIntrinsic::getPredicate(IID));
     if (isICmpTrue(Pred, Op0, Op1, Q.getWithoutUndef(), RecursionLimit))
       return Op0;
     if (isICmpTrue(Pred, Op1, Op0, Q.getWithoutUndef(), RecursionLimit))


        


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