Small tweak for branch optimizer (#95740)

dotnet · Dec 20, 2023 · 74f19df · 74f19df
1 parent 7e039e6
commit 74f19df
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/src/coreclr/jit/morph.cpp b/src/coreclr/jit/morph.cpp
@@ -9140,6 +9140,17 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
         case GT_GE:
         case GT_GT:
 
+            // Change "CNS relop op2" to "op2 relop* CNS"
+            if (!optValnumCSE_phase && op1->IsIntegralConst() && tree->OperIsCompare() && gtCanSwapOrder(op1, op2))
+            {
+                std::swap(tree->AsOp()->gtOp1, tree->AsOp()->gtOp2);
+                tree->gtOper = GenTree::SwapRelop(tree->OperGet());
+
+                oper = tree->OperGet();
+                op1  = tree->gtGetOp1();
+                op2  = tree->gtGetOp2();
+            }
+
             if (!optValnumCSE_phase && (op1->OperIs(GT_CAST) || op2->OperIs(GT_CAST)))
             {
                 tree = fgOptimizeRelationalComparisonWithCasts(tree->AsOp());