JIT: enhance RBO inference for similar compares to constants (#111766)

Thanks to #95234, RBO can draw inferences when the same value is compared to
different constants, if the initial comparison dominates and was false. Generalize this
to also handle cases where the initial comparison dominates and is true.

Fixes #111725.

Author: AndyAyersMS

src/coreclr/jit/redundantbranchopts.cpp

@@ -681,19 +681,21 @@ bool Compiler::optRelopTryInferWithOneEqualOperand(const VNFuncApp&      domApp,
     // BB4:
     //   return;
 
-    // Check whether the dominating compare being "false" implies the dominated compare is known
+    // Check whether the dominating compare being "true" or false" implies the dominated compare is known
     // to be either "true" or "false".
-    RelopResult treeOperStatus = IsCmp2ImpliedByCmp1(GenTree::ReverseRelop(domOper), domCns, treeOper, treeCns);
-    if (treeOperStatus == RelopResult::Unknown)
+    RelopResult ifTrueStatus  = IsCmp2ImpliedByCmp1(domOper, domCns, treeOper, treeCns);
+    RelopResult ifFalseStatus = IsCmp2ImpliedByCmp1(GenTree::ReverseRelop(domOper), domCns, treeOper, treeCns);
+
+    if ((ifTrueStatus == RelopResult::Unknown) && (ifFalseStatus == RelopResult::Unknown))
     {
         return false;
     }
 
     rii->canInfer          = true;
     rii->vnRelation        = ValueNumStore::VN_RELATION_KIND::VRK_Inferred;
-    rii->canInferFromTrue  = false;
-    rii->canInferFromFalse = true;
-    rii->reverseSense      = treeOperStatus == RelopResult::AlwaysTrue;
+    rii->canInferFromTrue  = (ifTrueStatus != RelopResult::Unknown);
+    rii->canInferFromFalse = (ifFalseStatus != RelopResult::Unknown);
+    rii->reverseSense      = (ifFalseStatus == RelopResult::AlwaysTrue) || (ifTrueStatus == RelopResult::AlwaysFalse);
     return true;
 }
 
@@ -832,10 +834,12 @@ bool Compiler::optRedundantBranch(BasicBlock* const block)
                     //
                     if (domIsInferredRelop)
                     {
-                        // This inference should be one-sided
+                        // We used to assert rii.canInferFromTrue ^ rii.canInferFromFalse here.
+                        //
+                        // But now we can find fully redundant compares with different relops,
+                        // eg LT x, 47 dominating LE x, 46. The second relop's value is equal to the first.
                         //
-                        assert(rii.canInferFromTrue ^ rii.canInferFromFalse);
-                        JITDUMP("\nDominator " FMT_BB " of " FMT_BB " has same VN operands but different relop\n",
+                        JITDUMP("\nDominator " FMT_BB " of " FMT_BB " can infer value of dominated relop\n",
                                 domBlock->bbNum, block->bbNum);
                     }
                     else