Fix IsVNConstantBound assert (#114486)

Author: EgorBo

src/coreclr/jit/assertionprop.cpp

@@ -5675,25 +5675,27 @@ bool Compiler::optCreateJumpTableImpliedAssertions(BasicBlock* switchBb)
             //           default: %name.Length is >= 8 here%
             //       }
             //
-            if (value > 0)
+            if ((value > 0) && !vnStore->IsVNConstant(opVN))
             {
                 AssertionDsc dsc   = {};
                 dsc.assertionKind  = OAK_NOT_EQUAL;
                 dsc.op2.kind       = O2K_CONST_INT;
                 dsc.op2.vn         = vnStore->VNZeroForType(TYP_INT);
                 dsc.op2.u1.iconVal = 0;
                 dsc.op2.SetIconFlag(GTF_EMPTY);
-                if (vnStore->IsVNCheckedBound(opVN))
+                if (vnStore->IsVNNeverNegative(opVN))
                 {
-                    // Create "arrBnd >= value" assertion
+                    // Create "X >= value" assertion (both operands are never negative)
                     dsc.op1.kind = O1K_CONSTANT_LOOP_BND;
                     dsc.op1.vn   = vnStore->VNForFunc(TYP_INT, VNF_GE, opVN, vnStore->VNForIntCon(value));
+                    assert(vnStore->IsVNConstantBound(dsc.op1.vn));
                 }
                 else
                 {
                     // Create "X u>= value" assertion
                     dsc.op1.kind = O1K_CONSTANT_LOOP_BND_UN;
                     dsc.op1.vn   = vnStore->VNForFunc(TYP_INT, VNF_GE_UN, opVN, vnStore->VNForIntCon(value));
+                    assert(vnStore->IsVNConstantBoundUnsigned(dsc.op1.vn));
                 }
                 newAssertIdx = optAddAssertion(&dsc);
             }

src/coreclr/jit/valuenum.cpp

@@ -6923,6 +6923,9 @@ bool ValueNumStore::IsVNConstantBound(ValueNum vn)
         {
             const bool op1IsConst = IsVNInt32Constant(funcApp.m_args[0]);
             const bool op2IsConst = IsVNInt32Constant(funcApp.m_args[1]);
+
+            // Technically, we can allow both to be constants,
+            // but such relops are expected to be constant folded anyway.
             return op1IsConst != op2IsConst;
         }
     }
@@ -6940,6 +6943,8 @@ bool ValueNumStore::IsVNConstantBoundUnsigned(ValueNum vn)
             case VNF_LE_UN:
             case VNF_GE_UN:
             case VNF_GT_UN:
+                // Technically, we can allow both to be constants,
+                // but such relops are expected to be constant folded anyway.
                 return IsVNPositiveInt32Constant(funcApp.m_args[0]) != IsVNPositiveInt32Constant(funcApp.m_args[1]);
             default:
                 break;