RFR: 8322790: RISC-V: Tune costs for shuffles with no conversion

[Ilya Gavrilin]

Hi all, please review this small change to RISC-V nodes insertion costs.
Now we have several nodes which provide shuffles without conversion: https://github.com/openjdk/jdk/blob/32d80e2caf6063b58128bd5f3dc87b276f3bd0cb/src/hotspot/cpu/riscv/riscv.ad#L8525-L8741
On most RISC-V cpu`s we prefer reg<->reg operations, because they are faster, but now stack<->reg operations used (for details about reasons, please, visit connected jbs issue).
After changing insertion costs reg<->reg operations selected, and we can see performance improvements for benchmarks, which use such shuffles (tested on thead C910 board):
|              Benchmark              | Upstream build (ops/ms) | Patched build (ops/ms) | difference (%) |
|:-----------------------------------:|:-----------------------:|:----------------------:|:--------------:|
| MathBench.doubleToRawLongBitsDouble |        30935.139        |        32171.761       |      +4.00      |
|      StrictMathBench.ceilDouble     |        24682.810        |        29782.050       |      +20.66     |
|      StrictMathBench.cosDouble      |         6948.309        |        6938.276        |      -0.14     |
|      StrictMathBench.expDouble      |         6816.143        |        7211.021        |      +5.79      |
|     StrictMathBench.floorDouble     |        30699.630        |        34189.509       |      +11.37     |
|      StrictMathBench.maxDouble      |        35157.355        |        34675.191       |      -1.37     |
|      StrictMathBench.minDouble      |        35192.135        |        35183.015       |      -0.03     |
|      StrictMathBench.sinDouble      |         6698.405        |        6721.809        |      +0.35      |

New benchmark for changed nodes:

--- a/test/micro/org/openjdk/bench/java/lang/MathBench.java
+++ b/test/micro/org/openjdk/bench/java/lang/MathBench.java
@@ -540,4 +540,11 @@ public class MathBench {
         return  Math.ulp(float7);
     }
 
+    @Benchmark
+    public long doubleToRawLongBitsDouble() {
+        double dbl162Dot5 = double81 * 2.0d + double0Dot5;
+        double dbl3 = double2 + double1;
+        return Double.doubleToRawLongBits(dbl162Dot5) + Double.doubleToRawLongBits(dbl3);
+    }
+

-------------

Commit messages:
 - Change costs for shuffles with no conversion

Changes: https://git.openjdk.org/jdk/pull/17206/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17206&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322790
  Stats: 13 lines in 1 file changed: 1 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/17206.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17206/head:pull/17206

PR: https://git.openjdk.org/jdk/pull/17206