[llvm] [RISCV] Account for ADDI immediate range in select of two constants w/ zicond (PR #155471)

[Craig Topper via llvm-commits]

================
@@ -9280,11 +9280,21 @@ SDValue RISCVTargetLowering::lowerSELECT(SDValue Op, SelectionDAG &DAG) const {
         }
       }
 
-      const int TrueValCost = RISCVMatInt::getIntMatCost(
-          TrueVal, Subtarget.getXLen(), Subtarget, /*CompressionCost=*/true);
-      const int FalseValCost = RISCVMatInt::getIntMatCost(
-          FalseVal, Subtarget.getXLen(), Subtarget, /*CompressionCost=*/true);
-      bool IsCZERO_NEZ = TrueValCost <= FalseValCost;
+      auto getCost = [&](APInt Delta, APInt Addend) {
+        const int DeltaCost = RISCVMatInt::getIntMatCost(
+            Delta, Subtarget.getXLen(), Subtarget, /*CompressionCost=*/true);
+        // Dos the addend folds into an ADDI
+        if (Addend.isSignedIntN(12))
+          return DeltaCost;
+        const int AddendCost = RISCVMatInt::getIntMatCost(
+            Addend, Subtarget.getXLen(), Subtarget, /*CompressionCost=*/true);
+        // Panalize the ADD slightly so that we prefer to end with an ADDI
----------------
topperc wrote:

```suggestion
        // Penalize the ADD slightly so that we prefer to end with an ADDI
```

https://github.com/llvm/llvm-project/pull/155471