[llvm] [llvm] add GenericFloatingPointPredicateUtils (PR #140254)

via llvm-commits llvm-commits at lists.llvm.org
Fri May 16 07:00:00 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-analysis

Author: Tim Gymnich (tgymnich)

<details>
<summary>Changes</summary>

- add `GenericFloatingPointPredicateUtils` in order to generalize effects of floating point comparisons on `KnownFPClass` for both IR and MIR.

---

Patch is 47.67 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/140254.diff


13 Files Affected:

- (added) llvm/include/llvm/ADT/GenericFloatingPointPredicateUtils.h (+479) 
- (added) llvm/include/llvm/Analysis/FloatingPointPredicateUtils.h (+74) 
- (modified) llvm/include/llvm/Analysis/ValueTracking.h (-43) 
- (added) llvm/include/llvm/CodeGen/MachineFloatingPointPredicateUtils.h (+52) 
- (modified) llvm/lib/Analysis/CMakeLists.txt (+1) 
- (added) llvm/lib/Analysis/FloatingPointPredicateUtils.cpp (+42) 
- (modified) llvm/lib/Analysis/InstructionSimplify.cpp (+1) 
- (modified) llvm/lib/Analysis/ValueTracking.cpp (+2-422) 
- (modified) llvm/lib/CodeGen/CMakeLists.txt (+1) 
- (modified) llvm/lib/CodeGen/CodeGenPrepare.cpp (+1) 
- (added) llvm/lib/CodeGen/MachineFloatingPointPredicateUtils.cpp (+49) 
- (modified) llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (+1) 
- (modified) llvm/unittests/Analysis/ValueTrackingTest.cpp (+1) 


``````````diff
diff --git a/llvm/include/llvm/ADT/GenericFloatingPointPredicateUtils.h b/llvm/include/llvm/ADT/GenericFloatingPointPredicateUtils.h
new file mode 100644
index 0000000000000..49c5fe0aed6e1
--- /dev/null
+++ b/llvm/include/llvm/ADT/GenericFloatingPointPredicateUtils.h
@@ -0,0 +1,479 @@
+//===- llvm/Support/GenericFloatingPointPredicateUtils.h -----*- C++-*-----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Utilities for dealing with flags related to floating point properties and
+/// mode controls.
+///
+//===----------------------------------------------------------------------===/
+
+#ifndef LLVM_ADT_GENERICFLOATINGPOINTPREDICATEUTILS_H
+#define LLVM_ADT_GENERICFLOATINGPOINTPREDICATEUTILS_H
+
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/FloatingPointMode.h"
+#include "llvm/IR/Instructions.h"
+#include <optional>
+
+namespace llvm {
+
+template <typename ContextT> class GenericFloatingPointPredicateUtils {
+  using ValueRefT = typename ContextT::ValueRefT;
+  using FunctionT = typename ContextT::FunctionT;
+
+  constexpr static ValueRefT Invalid = {};
+
+private:
+  static DenormalMode queryDenormalMode(const FunctionT &F, ValueRefT Val);
+
+  static bool lookThroughFAbs(const FunctionT &F, ValueRefT LHS,
+                              ValueRefT &Src);
+
+  static std::optional<APFloat> matchConstantFloat(const FunctionT &F,
+                                                   ValueRefT Val);
+
+  /// Return the return value for fcmpImpliesClass for a compare that produces
+  /// an exact class test.
+  static std::tuple<ValueRefT, FPClassTest, FPClassTest>
+  exactClass(ValueRefT V, FPClassTest M) {
+    return {V, M, ~M};
+  }
+
+public:
+  /// Returns a pair of values, which if passed to llvm.is.fpclass, returns the
+  /// same result as an fcmp with the given operands.
+  static std::pair<ValueRefT, FPClassTest>
+  fcmpToClassTest(FCmpInst::Predicate Pred, const FunctionT &F, ValueRefT LHS,
+                  ValueRefT RHS, bool LookThroughSrc) {
+    std::optional<APFloat> ConstRHS = matchConstantFloat(F, RHS);
+    if (!ConstRHS)
+      return {Invalid, fcAllFlags};
+
+    return fcmpToClassTest(Pred, F, LHS, *ConstRHS, LookThroughSrc);
+  }
+
+  static std::pair<ValueRefT, FPClassTest>
+  fcmpToClassTest(FCmpInst::Predicate Pred, const FunctionT &F, ValueRefT LHS,
+                  const APFloat &ConstRHS, bool LookThroughSrc) {
+
+    auto [Src, ClassIfTrue, ClassIfFalse] =
+        fcmpImpliesClass(Pred, F, LHS, ConstRHS, LookThroughSrc);
+
+    if (Src && ClassIfTrue == ~ClassIfFalse)
+      return {Src, ClassIfTrue};
+
+    return {Invalid, fcAllFlags};
+  }
+
+  /// Compute the possible floating-point classes that \p LHS could be based on
+  /// fcmp \Pred \p LHS, \p RHS.
+  ///
+  /// \returns { TestedValue, ClassesIfTrue, ClassesIfFalse }
+  ///
+  /// If the compare returns an exact class test, ClassesIfTrue ==
+  /// ~ClassesIfFalse
+  ///
+  /// This is a less exact version of fcmpToClassTest (e.g. fcmpToClassTest will
+  /// only succeed for a test of x > 0 implies positive, but not x > 1).
+  ///
+  /// If \p LookThroughSrc is true, consider the input value when computing the
+  /// mask. This may look through sign bit operations.
+  ///
+  /// If \p LookThroughSrc is false, ignore the source value (i.e. the first
+  /// pair element will always be LHS.
+  ///
+  static std::tuple<ValueRefT, FPClassTest, FPClassTest>
+  fcmpImpliesClass(CmpInst::Predicate Pred, const FunctionT &F, ValueRefT LHS,
+                   FPClassTest RHSClass, bool LookThroughSrc) {
+    assert(RHSClass != fcNone);
+    ValueRefT Src = LHS;
+
+    if (Pred == FCmpInst::FCMP_TRUE)
+      return exactClass(Src, fcAllFlags);
+
+    if (Pred == FCmpInst::FCMP_FALSE)
+      return exactClass(Src, fcNone);
+
+    const FPClassTest OrigClass = RHSClass;
+
+    const bool IsNegativeRHS = (RHSClass & fcNegative) == RHSClass;
+    const bool IsPositiveRHS = (RHSClass & fcPositive) == RHSClass;
+    const bool IsNaN = (RHSClass & ~fcNan) == fcNone;
+
+    if (IsNaN) {
+      // fcmp o__ x, nan -> false
+      // fcmp u__ x, nan -> true
+      return exactClass(Src, CmpInst::isOrdered(Pred) ? fcNone : fcAllFlags);
+    }
+
+    // fcmp ord x, zero|normal|subnormal|inf -> ~fcNan
+    if (Pred == FCmpInst::FCMP_ORD)
+      return exactClass(Src, ~fcNan);
+
+    // fcmp uno x, zero|normal|subnormal|inf -> fcNan
+    if (Pred == FCmpInst::FCMP_UNO)
+      return exactClass(Src, fcNan);
+
+    const bool IsFabs = LookThroughSrc && lookThroughFAbs(F, LHS, Src);
+    if (IsFabs)
+      RHSClass = llvm::inverse_fabs(RHSClass);
+
+    const bool IsZero = (OrigClass & fcZero) == OrigClass;
+    if (IsZero) {
+      assert(Pred != FCmpInst::FCMP_ORD && Pred != FCmpInst::FCMP_UNO);
+      // Compares with fcNone are only exactly equal to fcZero if input
+      // denormals are not flushed.
+      // TODO: Handle DAZ by expanding masks to cover subnormal cases.
+      DenormalMode Mode = queryDenormalMode(F, LHS);
+      if (Mode.Input != DenormalMode::IEEE)
+        return {Invalid, fcAllFlags, fcAllFlags};
+
+      switch (Pred) {
+      case FCmpInst::FCMP_OEQ: // Match x == 0.0
+        return exactClass(Src, fcZero);
+      case FCmpInst::FCMP_UEQ: // Match isnan(x) || (x == 0.0)
+        return exactClass(Src, fcZero | fcNan);
+      case FCmpInst::FCMP_UNE: // Match (x != 0.0)
+        return exactClass(Src, ~fcZero);
+      case FCmpInst::FCMP_ONE: // Match !isnan(x) && x != 0.0
+        return exactClass(Src, ~fcNan & ~fcZero);
+      case FCmpInst::FCMP_ORD:
+        // Canonical form of ord/uno is with a zero. We could also handle
+        // non-canonical other non-NaN constants or LHS == RHS.
+        return exactClass(Src, ~fcNan);
+      case FCmpInst::FCMP_UNO:
+        return exactClass(Src, fcNan);
+      case FCmpInst::FCMP_OGT: // x > 0
+        return exactClass(Src, fcPosSubnormal | fcPosNormal | fcPosInf);
+      case FCmpInst::FCMP_UGT: // isnan(x) || x > 0
+        return exactClass(Src, fcPosSubnormal | fcPosNormal | fcPosInf | fcNan);
+      case FCmpInst::FCMP_OGE: // x >= 0
+        return exactClass(Src, fcPositive | fcNegZero);
+      case FCmpInst::FCMP_UGE: // isnan(x) || x >= 0
+        return exactClass(Src, fcPositive | fcNegZero | fcNan);
+      case FCmpInst::FCMP_OLT: // x < 0
+        return exactClass(Src, fcNegSubnormal | fcNegNormal | fcNegInf);
+      case FCmpInst::FCMP_ULT: // isnan(x) || x < 0
+        return exactClass(Src, fcNegSubnormal | fcNegNormal | fcNegInf | fcNan);
+      case FCmpInst::FCMP_OLE: // x <= 0
+        return exactClass(Src, fcNegative | fcPosZero);
+      case FCmpInst::FCMP_ULE: // isnan(x) || x <= 0
+        return exactClass(Src, fcNegative | fcPosZero | fcNan);
+      default:
+        llvm_unreachable("all compare types are handled");
+      }
+
+      return {Invalid, fcAllFlags, fcAllFlags};
+    }
+
+    const bool IsDenormalRHS = (OrigClass & fcSubnormal) == OrigClass;
+
+    const bool IsInf = (OrigClass & fcInf) == OrigClass;
+    if (IsInf) {
+      FPClassTest Mask = fcAllFlags;
+
+      switch (Pred) {
+      case FCmpInst::FCMP_OEQ:
+      case FCmpInst::FCMP_UNE: {
+        // Match __builtin_isinf patterns
+        //
+        //   fcmp oeq x, +inf -> is_fpclass x, fcPosInf
+        //   fcmp oeq fabs(x), +inf -> is_fpclass x, fcInf
+        //   fcmp oeq x, -inf -> is_fpclass x, fcNegInf
+        //   fcmp oeq fabs(x), -inf -> is_fpclass x, 0 -> false
+        //
+        //   fcmp une x, +inf -> is_fpclass x, ~fcPosInf
+        //   fcmp une fabs(x), +inf -> is_fpclass x, ~fcInf
+        //   fcmp une x, -inf -> is_fpclass x, ~fcNegInf
+        //   fcmp une fabs(x), -inf -> is_fpclass x, fcAllFlags -> true
+        if (IsNegativeRHS) {
+          Mask = fcNegInf;
+          if (IsFabs)
+            Mask = fcNone;
+        } else {
+          Mask = fcPosInf;
+          if (IsFabs)
+            Mask |= fcNegInf;
+        }
+        break;
+      }
+      case FCmpInst::FCMP_ONE:
+      case FCmpInst::FCMP_UEQ: {
+        // Match __builtin_isinf patterns
+        //   fcmp one x, -inf -> is_fpclass x, fcNegInf
+        //   fcmp one fabs(x), -inf -> is_fpclass x, ~fcNegInf & ~fcNan
+        //   fcmp one x, +inf -> is_fpclass x, ~fcNegInf & ~fcNan
+        //   fcmp one fabs(x), +inf -> is_fpclass x, ~fcInf & fcNan
+        //
+        //   fcmp ueq x, +inf -> is_fpclass x, fcPosInf|fcNan
+        //   fcmp ueq (fabs x), +inf -> is_fpclass x, fcInf|fcNan
+        //   fcmp ueq x, -inf -> is_fpclass x, fcNegInf|fcNan
+        //   fcmp ueq fabs(x), -inf -> is_fpclass x, fcNan
+        if (IsNegativeRHS) {
+          Mask = ~fcNegInf & ~fcNan;
+          if (IsFabs)
+            Mask = ~fcNan;
+        } else {
+          Mask = ~fcPosInf & ~fcNan;
+          if (IsFabs)
+            Mask &= ~fcNegInf;
+        }
+
+        break;
+      }
+      case FCmpInst::FCMP_OLT:
+      case FCmpInst::FCMP_UGE: {
+        if (IsNegativeRHS) {
+          // No value is ordered and less than negative infinity.
+          // All values are unordered with or at least negative infinity.
+          // fcmp olt x, -inf -> false
+          // fcmp uge x, -inf -> true
+          Mask = fcNone;
+          break;
+        }
+
+        // fcmp olt fabs(x), +inf -> fcFinite
+        // fcmp uge fabs(x), +inf -> ~fcFinite
+        // fcmp olt x, +inf -> fcFinite|fcNegInf
+        // fcmp uge x, +inf -> ~(fcFinite|fcNegInf)
+        Mask = fcFinite;
+        if (!IsFabs)
+          Mask |= fcNegInf;
+        break;
+      }
+      case FCmpInst::FCMP_OGE:
+      case FCmpInst::FCMP_ULT: {
+        if (IsNegativeRHS) {
+          // fcmp oge x, -inf -> ~fcNan
+          // fcmp oge fabs(x), -inf -> ~fcNan
+          // fcmp ult x, -inf -> fcNan
+          // fcmp ult fabs(x), -inf -> fcNan
+          Mask = ~fcNan;
+          break;
+        }
+
+        // fcmp oge fabs(x), +inf -> fcInf
+        // fcmp oge x, +inf -> fcPosInf
+        // fcmp ult fabs(x), +inf -> ~fcInf
+        // fcmp ult x, +inf -> ~fcPosInf
+        Mask = fcPosInf;
+        if (IsFabs)
+          Mask |= fcNegInf;
+        break;
+      }
+      case FCmpInst::FCMP_OGT:
+      case FCmpInst::FCMP_ULE: {
+        if (IsNegativeRHS) {
+          // fcmp ogt x, -inf -> fcmp one x, -inf
+          // fcmp ogt fabs(x), -inf -> fcmp ord x, x
+          // fcmp ule x, -inf -> fcmp ueq x, -inf
+          // fcmp ule fabs(x), -inf -> fcmp uno x, x
+          Mask = IsFabs ? ~fcNan : ~(fcNegInf | fcNan);
+          break;
+        }
+
+        // No value is ordered and greater than infinity.
+        Mask = fcNone;
+        break;
+      }
+      case FCmpInst::FCMP_OLE:
+      case FCmpInst::FCMP_UGT: {
+        if (IsNegativeRHS) {
+          Mask = IsFabs ? fcNone : fcNegInf;
+          break;
+        }
+
+        // fcmp ole x, +inf -> fcmp ord x, x
+        // fcmp ole fabs(x), +inf -> fcmp ord x, x
+        // fcmp ole x, -inf -> fcmp oeq x, -inf
+        // fcmp ole fabs(x), -inf -> false
+        Mask = ~fcNan;
+        break;
+      }
+      default:
+        llvm_unreachable("all compare types are handled");
+      }
+
+      // Invert the comparison for the unordered cases.
+      if (FCmpInst::isUnordered(Pred))
+        Mask = ~Mask;
+
+      return exactClass(Src, Mask);
+    }
+
+    if (Pred == FCmpInst::FCMP_OEQ)
+      return {Src, RHSClass, fcAllFlags};
+
+    if (Pred == FCmpInst::FCMP_UEQ) {
+      FPClassTest Class = RHSClass | fcNan;
+      return {Src, Class, ~fcNan};
+    }
+
+    if (Pred == FCmpInst::FCMP_ONE)
+      return {Src, ~fcNan, RHSClass | fcNan};
+
+    if (Pred == FCmpInst::FCMP_UNE)
+      return {Src, fcAllFlags, RHSClass};
+
+    assert((RHSClass == fcNone || RHSClass == fcPosNormal ||
+            RHSClass == fcNegNormal || RHSClass == fcNormal ||
+            RHSClass == fcPosSubnormal || RHSClass == fcNegSubnormal ||
+            RHSClass == fcSubnormal) &&
+           "should have been recognized as an exact class test");
+
+    if (IsNegativeRHS) {
+      // TODO: Handle fneg(fabs)
+      if (IsFabs) {
+        // fabs(x) o> -k -> fcmp ord x, x
+        // fabs(x) u> -k -> true
+        // fabs(x) o< -k -> false
+        // fabs(x) u< -k -> fcmp uno x, x
+        switch (Pred) {
+        case FCmpInst::FCMP_OGT:
+        case FCmpInst::FCMP_OGE:
+          return {Src, ~fcNan, fcNan};
+        case FCmpInst::FCMP_UGT:
+        case FCmpInst::FCMP_UGE:
+          return {Src, fcAllFlags, fcNone};
+        case FCmpInst::FCMP_OLT:
+        case FCmpInst::FCMP_OLE:
+          return {Src, fcNone, fcAllFlags};
+        case FCmpInst::FCMP_ULT:
+        case FCmpInst::FCMP_ULE:
+          return {Src, fcNan, ~fcNan};
+        default:
+          break;
+        }
+
+        return {Invalid, fcAllFlags, fcAllFlags};
+      }
+
+      FPClassTest ClassesLE = fcNegInf | fcNegNormal;
+      FPClassTest ClassesGE = fcPositive | fcNegZero | fcNegSubnormal;
+
+      if (IsDenormalRHS)
+        ClassesLE |= fcNegSubnormal;
+      else
+        ClassesGE |= fcNegNormal;
+
+      switch (Pred) {
+      case FCmpInst::FCMP_OGT:
+      case FCmpInst::FCMP_OGE:
+        return {Src, ClassesGE, ~ClassesGE | RHSClass};
+      case FCmpInst::FCMP_UGT:
+      case FCmpInst::FCMP_UGE:
+        return {Src, ClassesGE | fcNan, ~(ClassesGE | fcNan) | RHSClass};
+      case FCmpInst::FCMP_OLT:
+      case FCmpInst::FCMP_OLE:
+        return {Src, ClassesLE, ~ClassesLE | RHSClass};
+      case FCmpInst::FCMP_ULT:
+      case FCmpInst::FCMP_ULE:
+        return {Src, ClassesLE | fcNan, ~(ClassesLE | fcNan) | RHSClass};
+      default:
+        break;
+      }
+    } else if (IsPositiveRHS) {
+      FPClassTest ClassesGE = fcPosNormal | fcPosInf;
+      FPClassTest ClassesLE = fcNegative | fcPosZero | fcPosSubnormal;
+      if (IsDenormalRHS)
+        ClassesGE |= fcPosSubnormal;
+      else
+        ClassesLE |= fcPosNormal;
+
+      if (IsFabs) {
+        ClassesGE = llvm::inverse_fabs(ClassesGE);
+        ClassesLE = llvm::inverse_fabs(ClassesLE);
+      }
+
+      switch (Pred) {
+      case FCmpInst::FCMP_OGT:
+      case FCmpInst::FCMP_OGE:
+        return {Src, ClassesGE, ~ClassesGE | RHSClass};
+      case FCmpInst::FCMP_UGT:
+      case FCmpInst::FCMP_UGE:
+        return {Src, ClassesGE | fcNan, ~(ClassesGE | fcNan) | RHSClass};
+      case FCmpInst::FCMP_OLT:
+      case FCmpInst::FCMP_OLE:
+        return {Src, ClassesLE, ~ClassesLE | RHSClass};
+      case FCmpInst::FCMP_ULT:
+      case FCmpInst::FCMP_ULE:
+        return {Src, ClassesLE | fcNan, ~(ClassesLE | fcNan) | RHSClass};
+      default:
+        break;
+      }
+    }
+
+    return {Invalid, fcAllFlags, fcAllFlags};
+  }
+
+  static std::tuple<ValueRefT, FPClassTest, FPClassTest>
+  fcmpImpliesClass(CmpInst::Predicate Pred, const FunctionT &F, ValueRefT LHS,
+                   const APFloat &ConstRHS, bool LookThroughSrc) {
+    // We can refine checks against smallest normal / largest denormal to an
+    // exact class test.
+    if (!ConstRHS.isNegative() && ConstRHS.isSmallestNormalized()) {
+      ValueRefT Src = LHS;
+      const bool IsFabs = LookThroughSrc && lookThroughFAbs(F, LHS, Src);
+
+      FPClassTest Mask;
+      // Match pattern that's used in __builtin_isnormal.
+      switch (Pred) {
+      case FCmpInst::FCMP_OLT:
+      case FCmpInst::FCMP_UGE: {
+        // fcmp olt x, smallest_normal ->
+        // fcNegInf|fcNegNormal|fcSubnormal|fcZero fcmp olt fabs(x),
+        // smallest_normal -> fcSubnormal|fcZero fcmp uge x, smallest_normal ->
+        // fcNan|fcPosNormal|fcPosInf fcmp uge fabs(x), smallest_normal ->
+        // ~(fcSubnormal|fcZero)
+        Mask = fcZero | fcSubnormal;
+        if (!IsFabs)
+          Mask |= fcNegNormal | fcNegInf;
+
+        break;
+      }
+      case FCmpInst::FCMP_OGE:
+      case FCmpInst::FCMP_ULT: {
+        // fcmp oge x, smallest_normal -> fcPosNormal | fcPosInf
+        // fcmp oge fabs(x), smallest_normal -> fcInf | fcNormal
+        // fcmp ult x, smallest_normal -> ~(fcPosNormal | fcPosInf)
+        // fcmp ult fabs(x), smallest_normal -> ~(fcInf | fcNormal)
+        Mask = fcPosInf | fcPosNormal;
+        if (IsFabs)
+          Mask |= fcNegInf | fcNegNormal;
+        break;
+      }
+      default:
+        return fcmpImpliesClass(Pred, F, LHS, ConstRHS.classify(),
+                                LookThroughSrc);
+      }
+
+      // Invert the comparison for the unordered cases.
+      if (FCmpInst::isUnordered(Pred))
+        Mask = ~Mask;
+
+      return exactClass(Src, Mask);
+    }
+
+    return fcmpImpliesClass(Pred, F, LHS, ConstRHS.classify(), LookThroughSrc);
+  }
+
+  static std::tuple<ValueRefT, FPClassTest, FPClassTest>
+  fcmpImpliesClass(CmpInst::Predicate Pred, const FunctionT &F, ValueRefT LHS,
+                   ValueRefT RHS, bool LookThroughSrc) {
+    std::optional<APFloat> ConstRHS = matchConstantFloat(F, RHS);
+    if (!ConstRHS)
+      return {Invalid, fcAllFlags, fcAllFlags};
+
+    // TODO: Just call computeKnownFPClass for RHS to handle non-constants.
+    return fcmpImpliesClass(Pred, F, LHS, *ConstRHS, LookThroughSrc);
+  }
+};
+
+} // namespace llvm
+
+#endif // LLVM_ADT_GENERICFLOATINGPOINTPREDICATEUTILS_H
diff --git a/llvm/include/llvm/Analysis/FloatingPointPredicateUtils.h b/llvm/include/llvm/Analysis/FloatingPointPredicateUtils.h
new file mode 100644
index 0000000000000..68c9876988fbc
--- /dev/null
+++ b/llvm/include/llvm/Analysis/FloatingPointPredicateUtils.h
@@ -0,0 +1,74 @@
+//===- llvm/Analysis/FloatingPointPredicateUtils.h ----------------*- C++
+//-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_FLOATINGPOINTPREDICATEUTILS_H
+#define LLVM_ANALYSIS_FLOATINGPOINTPREDICATEUTILS_H
+
+#include "llvm/ADT/GenericFloatingPointPredicateUtils.h"
+#include "llvm/IR/SSAContext.h"
+
+namespace llvm {
+
+using FloatingPointPredicateUtils =
+    GenericFloatingPointPredicateUtils<SSAContext>;
+
+/// Returns a pair of values, which if passed to llvm.is.fpclass, returns the
+/// same result as an fcmp with the given operands.
+///
+/// If \p LookThroughSrc is true, consider the input value when computing the
+/// mask.
+///
+/// If \p LookThroughSrc is false, ignore the source value (i.e. the first pair
+/// element will always be LHS.
+inline std::pair<Value *, FPClassTest>
+fcmpToClassTest(FCmpInst::Predicate Pred, const Function &F, Value *LHS,
+                Value *RHS, bool LookThroughSrc = true) {
+  return FloatingPointPredicateUtils::fcmpToClassTest(Pred, F, LHS, RHS,
+                                                      LookThroughSrc = true);
+}
+
+/// Returns a pair of values, which if passed to llvm.is.fpclass, returns the
+/// same result as an fcmp with the given operands.
+///
+/// If \p LookThroughSrc is true, consider the input value when computing the
+/// mask.
+///
+/// If \p LookThroughSrc is false, ignore the source value (i.e. the first pair
+/// element will always be LHS.
+inline std::pair<Value *, FPClassTest>
+fcmpToClassTest(FCmpInst::Predicate Pred, const Function &F, Value *LHS,
+                const APFloat *ConstRHS, bool LookThroughSrc = true) {
+  return FloatingPointPredicateUtils::fcmpToClassTest(Pred, F, LHS, *ConstRHS,
+                                                      LookThroughSrc);
+}
+
+inline std::tuple<Value *, FPClassTest, FPClassTest>
+fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
+                 FPClassTest RHSClass, bool LookThroughSrc = true) {
+  return FloatingPointPredicateUtils::fcmpImpliesClass(Pred, F, LHS, RHSClass,
+                                                       LookThroughSrc);
+}
+
+inline std::tuple<Value *, FPClassTest, FPClassTest>
+fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
+                 const APFloat &ConstRHS, bool LookThroughSrc = true) {
+  return FloatingPointPredicateUtils::fcmpImpliesClass(Pred, F, LHS, ConstRHS...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/140254


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