[llvm] [RISCV] Accept [-128, 255] instead of [0, 255] for pli.b (PR #153913)

[Sam Elliott via llvm-commits]

================
@@ -18,7 +18,26 @@
 // Operand and SDNode transformation definitions.
 //===----------------------------------------------------------------------===//
 
-def simm10 : RISCVSImmLeafOp<10>;
+def simm10 : RISCVSImmOp<10>;
+
+def SImm8UnsignedAsmOperand : SImmAsmOperand<8, "Unsigned"> {
+  let RenderMethod = "addSImm8UnsignedOperands";
+}
+
+// A 8-bit signed immediate allowing range [-128, 255]
+// but represented as [-128, 255].
----------------
lenary wrote:

Oops, missed this minor comment issue.

```suggestion
// but represented as [-128, 127].
```


https://github.com/llvm/llvm-project/pull/153913