[RISCV] Correct the immediate swizzling for P-ext plui.h/w. (llvm#149945)

If I'm reading the spec correctly, plui.h/w encode the immediate
differently from pli.h/w. pli.h/w appear to rotate the immediate
left by 1 before encoding while plui.h/w rotates the immediate right
by 1 before encoding.

Since I was splitting the classes, I made the name closer to the
instruction names since the immediate width was ambiguous. I've
added an _i suffix to make it similar to base and Zb* class names.

Author: topperc

llvm/lib/Target/RISCV/RISCVInstrInfoP.td

@@ -44,9 +44,8 @@ def simm10_unsigned : RISCVOp {
 //===----------------------------------------------------------------------===//
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
-class RVPLoadImm10<bits<7> funct7, string opcodestr,
-                   DAGOperand TyImm10 = simm10>
-    : RVInst<(outs GPR:$rd), (ins TyImm10:$imm10), opcodestr, "$rd, $imm10", [],
+class PLI_i<bits<7> funct7, string opcodestr>
+    : RVInst<(outs GPR:$rd), (ins simm10:$imm10), opcodestr, "$rd, $imm10", [],
              InstFormatOther> {
   bits<10> imm10;
   bits<5> rd;
@@ -60,7 +59,22 @@ class RVPLoadImm10<bits<7> funct7, string opcodestr,
 }
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
-class RVPLoadImm8<bits<8> funct8, string opcodestr>
+class PLUI_i<bits<7> funct7, string opcodestr>
+    : RVInst<(outs GPR:$rd), (ins simm10_unsigned:$imm10), opcodestr,
+             "$rd, $imm10", [], InstFormatOther> {
+  bits<10> imm10;
+  bits<5> rd;
+
+  let Inst{31-25} = funct7;
+  let Inst{24}    = imm10{0};
+  let Inst{23-15} = imm10{9-1};
+  let Inst{14-12} = 0b010;
+  let Inst{11-7} = rd;
+  let Inst{6-0} = OPC_OP_IMM_32.Value;
+}
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class PLI_B_i<bits<8> funct8, string opcodestr>
     : RVInst<(outs GPR:$rd), (ins uimm8:$uimm8), opcodestr, "$rd, $uimm8", [],
              InstFormatOther> {
   bits<8> uimm8;
@@ -148,11 +162,11 @@ def PSSLAI_W : RVPUnaryImm5<0b101, "psslai.w">;
 } // Predicates = [HasStdExtP, IsRV64]
 
 let Predicates = [HasStdExtP] in
-def PLI_H : RVPLoadImm10<0b1011000, "pli.h">;
+def PLI_H : PLI_i<0b1011000, "pli.h">;
 let Predicates = [HasStdExtP, IsRV64] in
-def PLI_W : RVPLoadImm10<0b1011001, "pli.w">;
+def PLI_W : PLI_i<0b1011001, "pli.w">;
 let Predicates = [HasStdExtP] in
-def PLI_B : RVPLoadImm8<0b10110100, "pli.b">;
+def PLI_B : PLI_B_i<0b10110100, "pli.b">;
 
 let Predicates = [HasStdExtP] in {
 def PSEXT_H_B : RVPUnaryWUF<0b00, 0b00100, "psext.h.b">;
@@ -165,6 +179,6 @@ def PSEXT_W_H      : RVPUnaryWUF<0b01, 0b00101, "psext.w.h">;
 } // Predicates = [HasStdExtP, IsRV64]
 
 let Predicates = [HasStdExtP] in
-def PLUI_H : RVPLoadImm10<0b1111000, "plui.h", simm10_unsigned>;
+def PLUI_H : PLUI_i<0b1111000, "plui.h">;
 let Predicates = [HasStdExtP, IsRV64] in
-def PLUI_W : RVPLoadImm10<0b1111001, "plui.w", simm10_unsigned>;
+def PLUI_W : PLUI_i<0b1111001, "plui.w">;

llvm/test/MC/RISCV/rv32p-valid.s

@@ -71,8 +71,8 @@ psabs.h a1, a2
 # CHECK-ASM: encoding: [0x9b,0x22,0x73,0xe4]
 psabs.b t0, t1
 # CHECK-ASM-AND-OBJ: plui.h gp, 32
-# CHECK-ASM: encoding: [0x9b,0x21,0x20,0xf0]
+# CHECK-ASM: encoding: [0x9b,0x21,0x08,0xf0]
 plui.h gp, 32
 # CHECK-ASM-AND-OBJ: plui.h gp, -412
-# CHECK-ASM: encoding: [0x9b,0xa1,0x64,0xf0]
+# CHECK-ASM: encoding: [0x9b,0x21,0x99,0xf0]
 plui.h gp, 612

llvm/test/MC/RISCV/rv64p-valid.s

@@ -95,13 +95,13 @@ psabs.h t1, t5
 # CHECK-ASM: encoding: [0x1b,0x25,0x79,0xe4]
 psabs.b a0, s2
 # CHECK-ASM-AND-OBJ: plui.h s2, 4
-# CHECK-ASM: encoding: [0x1b,0x29,0x04,0xf0]
+# CHECK-ASM: encoding: [0x1b,0x29,0x01,0xf0]
 plui.h s2, 4
 # CHECK-ASM-AND-OBJ: plui.h gp, -412
-# CHECK-ASM: encoding: [0x9b,0xa1,0x64,0xf0]
+# CHECK-ASM: encoding: [0x9b,0x21,0x99,0xf0]
 plui.h gp, 612
 # CHECK-ASM-AND-OBJ: plui.w a2, 1
-# CHECK-ASM: encoding: [0x1b,0x26,0x01,0xf2]
+# CHECK-ASM: encoding: [0x1b,0x26,0x00,0xf3]
 plui.w a2, 1
 # CHECK-ASM-AND-OBJ: plui.w a2, -1
 # CHECK-ASM: encoding: [0x1b,0xa6,0xff,0xf3]