Optimization for full range checks (#70145)

src/coreclr/jit/compiler.h

@@ -1242,6 +1242,16 @@ class IntegralRange
         assert(lowerBound <= upperBound);
     }
 
+    SymbolicIntegerValue GetLowerBound()
+    {
+        return m_lowerBound;
+    }
+
+    SymbolicIntegerValue GetUpperBound()
+    {
+        return m_upperBound;
+    }
+
     bool Contains(int64_t value) const;
 
     bool Contains(IntegralRange other) const
@@ -5690,6 +5700,7 @@ class Compiler
     GenTree* fgOptimizeCast(GenTreeCast* cast);
     GenTree* fgOptimizeEqualityComparisonWithConst(GenTreeOp* cmp);
     GenTree* fgOptimizeRelationalComparisonWithConst(GenTreeOp* cmp);
+    GenTree* fgOptimizeRelationalComparisonWithFullRangeConst(GenTreeOp* cmp);
 #ifdef FEATURE_HW_INTRINSICS
     GenTree* fgOptimizeHWIntrinsic(GenTreeHWIntrinsic* node);
 #endif

src/coreclr/jit/morph.cpp

@@ -11406,6 +11406,21 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac)
                 assert(op2 == tree->AsOp()->gtGetOp2());
             }
 
+            if (opts.OptimizationEnabled() && fgGlobalMorph)
+            {
+                if (op2->IsIntegralConst() || op1->IsIntegralConst())
+                {
+                    if (tree->OperIs(GT_GT, GT_LT, GT_LE, GT_GE))
+                    {
+                        tree = fgOptimizeRelationalComparisonWithFullRangeConst(tree->AsOp());
+                        if (tree->OperIs(GT_CNS_INT, GT_COMMA))
+                        {
+                            return tree;
+                        }
+                    }
+                }
+            }
+
         COMPARE:
 
             noway_assert(tree->OperIsCompare());
@@ -12631,6 +12646,90 @@ GenTree* Compiler::fgOptimizeEqualityComparisonWithConst(GenTreeOp* cmp)
     return cmp;
 }
 
+//------------------------------------------------------------------------
+// fgOptimizeRelationalComparisonWithFullRangeConst: optimizes a comparison operation.
+//
+// Recognizes "Always false" comparisons against various full range constant operands and morphs
+// them into zero.
+//
+// Arguments:
+//   cmp - the GT_LT/GT_GT tree to morph.
+//
+// Return Value:
+//   1. The unmodified "cmp" tree.
+//   2. A CNS_INT node containing zero.
+//   3. A GT_COMMA node containing side effects along with a CNS_INT node containing zero
+// Assumptions:
+//   The second operand is an integral constant or the first operand is an integral constant.
+//
+GenTree* Compiler::fgOptimizeRelationalComparisonWithFullRangeConst(GenTreeOp* cmp)
+{
+
+    int64_t lhsMin;
+    int64_t lhsMax;
+    if (cmp->gtGetOp1()->IsIntegralConst())
+    {
+        lhsMin = cmp->gtGetOp1()->AsIntConCommon()->IntegralValue();
+        lhsMax = lhsMin;
+    }
+    else
+    {
+        IntegralRange lhsRange = IntegralRange::ForNode(cmp->gtGetOp1(), this);
+        lhsMin                 = IntegralRange::SymbolicToRealValue(lhsRange.GetLowerBound());
+        lhsMax                 = IntegralRange::SymbolicToRealValue(lhsRange.GetUpperBound());
+    }
+
+    int64_t rhsMin;
+    int64_t rhsMax;
+    if (cmp->gtGetOp2()->IsIntegralConst())
+    {
+        rhsMin = cmp->gtGetOp2()->AsIntConCommon()->IntegralValue();
+        rhsMax = rhsMin;
+    }
+    else
+    {
+        IntegralRange rhsRange = IntegralRange::ForNode(cmp->gtGetOp2(), this);
+        rhsMin                 = IntegralRange::SymbolicToRealValue(rhsRange.GetLowerBound());
+        rhsMax                 = IntegralRange::SymbolicToRealValue(rhsRange.GetUpperBound());
+    }
+
+    genTreeOps op = cmp->gtOper;
+    if ((op != GT_LT) && (op != GT_LE))
+    {
+        op = GenTree::SwapRelop(op);
+        std::swap(lhsMin, rhsMin);
+        std::swap(lhsMax, rhsMax);
+    }
+
+    int64_t lefOpValue   = lhsMin;
+    int64_t rightOpValue = rhsMax;
+
+    if (cmp->IsUnsigned() && lefOpValue == -1 && lhsMax == -1)
+    {
+        rightOpValue = -1;
+    }
+
+    if ((op == GT_LT && lefOpValue == rightOpValue) || (op == GT_LE && lefOpValue > rightOpValue))
+    {
+        GenTree* ret = gtNewZeroConNode(TYP_INT);
+
+        if (gtTreeHasSideEffects(cmp, GTF_SIDE_EFFECT))
+        {
+            return cmp;
+        }
+
+        ret->SetVNsFromNode(cmp);
+
+        DEBUG_DESTROY_NODE(cmp);
+
+        INDEBUG(ret->gtDebugFlags |= GTF_DEBUG_NODE_MORPHED);
+
+        return ret;
+    }
+
+    return cmp;
+}
+
 //------------------------------------------------------------------------
 // fgOptimizeRelationalComparisonWithConst: optimizes a comparison operation.
 //

src/tests/JIT/opt/Compares/compares.cs

@@ -0,0 +1,204 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// unit test for the full range comparison optimization
+
+using System;
+using System.Runtime.CompilerServices;
+
+public class FullRangeComparisonTest
+{
+    // Class for testing side effects promotion
+    public class SideEffects
+    { 
+        public byte B;
+    } 
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MinValue_RHSConst_Byte(byte b) => b >= 0;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MinValue_RHSConst_Short(short s) => s >= short.MinValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MinValue_RHSConst_Int(int i) => i >= int.MinValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MinValue_RHSConst_Long(long l) => l >= long.MinValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_Byte(byte b) => b <= byte.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_Short(short s) => s <= short.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_Int(int i) => i <= int.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_Long(long l) => l <= long.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_UShort(ushort us) => us <= ushort.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_UInt(uint ui) => ui <= uint.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MaxValue_RHSConst_ULong(ulong ul) => ul <= uint.MaxValue;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MinValue_LHSConst_Byte(byte b) => 0 <= b;
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MinValue_LHSConst_Short(short i) => short.MinValue <= i;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MinValue_LHSConst_Int(int i) => int.MinValue <= i;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrLessThan_MinValue_LHSConst_Long(long l) => long.MinValue <= l;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MaxValue_LHSConst_Byte(byte b) => byte.MaxValue >= b;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MaxValue_LHSConst_Short(short s) => short.MaxValue >= s;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MaxValue_LHSConst_Int(int i) => int.MaxValue >= i;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MaxValue_LHSConst_Long(long l) => long.MaxValue >= l;
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool EqualsOrGreaterThan_MaxValue_LHSConst_SideEffects(SideEffects c) => c.B <= 255;
+    public static int Main()
+    {
+        // Optimize comparison with full range values
+        // RHS Const Optimization
+        if (!EqualsOrGreaterThan_MinValue_RHSConst_Byte(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MinValue_RHSConst_Byte(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MinValue_RHSConst_Short(-10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MinValue_RHSConst_Short(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MinValue_RHSConst_Int(-10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MinValue_RHSConst_Int(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MinValue_RHSConst_Long(-10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MinValue_RHSConst_Long(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_Byte(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_Byte(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_Short(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_Short(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_Int(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_Int(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_Long(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_Long(10) failed");
+            return 101;
+        }
+
+        // LHS Const Optimization
+        if (!EqualsOrLessThan_MinValue_LHSConst_Byte(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MinValue_LHSConst_Byte(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MinValue_LHSConst_Int(-10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MinValue_LHSConst_Int(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MinValue_LHSConst_Long(-10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MinValue_LHSConst_Long(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MaxValue_LHSConst_Byte(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MaxValue_LHSConst_Byte(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MaxValue_LHSConst_Int(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MaxValue_LHSConst_Int(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrGreaterThan_MaxValue_LHSConst_Long(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MaxValue_LHSConst_Long(10) failed");
+            return 101;
+        }
+
+
+        // Unsigned values
+        if (!EqualsOrLessThan_MaxValue_RHSConst_UShort(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_UShort(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_UInt(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_UInt(10) failed");
+            return 101;
+        }
+
+        if (!EqualsOrLessThan_MaxValue_RHSConst_ULong(10))
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrLessThan_MaxValue_RHSConst_ULong(10) failed");
+            return 101;
+        }
+
+        // Side effects persist
+        try
+        {
+            EqualsOrGreaterThan_MaxValue_LHSConst_SideEffects(null);
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MaxValue_LHSConst_SideEffects(null) failed");
+            return 101;
+        }
+        catch (NullReferenceException ex)
+        {
+
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("FullRangeComparisonTest:EqualsOrGreaterThan_MaxValue_LHSConst_SideEffects(null) failed");
+            return 101;
+        }
+
+        Console.WriteLine("PASSED");
+        return 100;
+    }
+}

src/tests/JIT/opt/Compares/compares.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+  </PropertyGroup>
+  <PropertyGroup>
+    <DebugType>PdbOnly</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>