[SPARC] Add GNU syntax extensions of WRPR instruction

[koakuma]

Summary

Add two GNU extension forms of wrpr:

1. wrpr %reg, %rd -> wrpr %reg, %g0, %rd
2. wrpr imm, %rd -> wrpr %g0, imm, %rd

Note: since the semantics of wrpr %rs1, %rs2/imm, %rd is %rd <- (%rs1 xor %rs2/imm), in case (1) it technically doesn't matter whether the %g0 is placed as the first or second operand, however, I'm placing it as the second operand to match the encoding of GNU as.

This fixes the wrpr instruction part of bug #40792 (https://github.com/llvm/llvm-project/issues/40792).

[arsenm]

I don't know any of the context but the change itself looks fine

llvm/lib/Target/Sparc/SparcInstrAliases.td

 def : InstAlias<"wr $rs2, %wim", (WRWIMrr G0, IntRegs:$rs2), 0>;
 def : InstAlias<"wr $simm13, %wim", (WRWIMri G0, i32imm:$simm13), 0>;
 def : InstAlias<"wr $rs2, %tbr", (WRTBRrr G0, IntRegs:$rs2), 0>;
 def : InstAlias<"wr $simm13, %tbr", (WRTBRri G0, i32imm:$simm13), 0>;
 
 def : InstAlias<"pwr $rs2, %psr", (PWRPSRrr G0, IntRegs:$rs2), 0>;
 def : InstAlias<"pwr $simm13, %psr", (PWRPSRri G0, i32imm:$simm13), 0>;
 
+// wrpr %reg, %rd -> wrpr %reg, %g0, %rd
+// wrpr  imm, %rd -> wrpr  %g0, imm, %rd
+// Nonstandard GNU extensions.
+let Predicates = [HasV9] in {
+  def : InstAlias<"wrpr $rs1, $rd", (WRPRrr PRRegs:$rd, IntRegs:$rs1, G0), 0>;
+  def : InstAlias<"wrpr $simm13, $rd", (WRPRri PRRegs:$rd, G0, i32imm:$simm13), 0>;
+}
+
 // flush -> flush %g0
 def : InstAlias<"flush", (FLUSH), 0>;
 
 // unimp -> unimp 0
 def : InstAlias<"unimp", (UNIMP 0), 0>;
 
 def : MnemonicAlias<"iflush", "flush">;
 

llvm/test/MC/Sparc/sparcv9-instructions.s

! RUN: llvm-mc %s -arch=sparcv9 -show-encoding | FileCheck %s --check-prefix=V9
         ! V9: wrpr %g6, 255, %otherwin   ! encoding: [0x9b,0x91,0xa0,0xff]
         wrpr %g6,255,%otherwin
         ! V8:      error: instruction requires a CPU feature not currently enabled
         ! V8-NEXT: wrpr %g6,255,%wstate
         ! V9: wrpr %g6, 255, %wstate     ! encoding: [0x9d,0x91,0xa0,0xff]
         wrpr %g6,255,%wstate
 
         ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tpc
+        ! V9: wrpr %fp, %g0, %tpc        ! encoding: [0x81,0x97,0x80,0x00]
+        wrpr %i6,%tpc
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tnpc
+        ! V9: wrpr %fp, %g0, %tnpc       ! encoding: [0x83,0x97,0x80,0x00]
+        wrpr %i6,%tnpc
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tstate
+        ! V9: wrpr %fp, %g0, %tstate     ! encoding: [0x85,0x97,0x80,0x00]
+        wrpr %i6,%tstate
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tt
+        ! V9: wrpr %fp, %g0, %tt         ! encoding: [0x87,0x97,0x80,0x00]
+        wrpr %i6,%tt
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tick
+        ! V9: wrpr %fp, %g0, %tick       ! encoding: [0x89,0x97,0x80,0x00]
+        wrpr %i6,%tick
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tba
+        ! V9: wrpr %fp, %g0, %tba        ! encoding: [0x8b,0x97,0x80,0x00]
+        wrpr %i6,%tba
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%pstate
+        ! V9: wrpr %fp, %g0, %pstate     ! encoding: [0x8d,0x97,0x80,0x00]
+        wrpr %i6,%pstate
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%tl
+        ! V9: wrpr %fp, %g0, %tl         ! encoding: [0x8f,0x97,0x80,0x00]
+        wrpr %i6,%tl
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%pil
+        ! V9: wrpr %fp, %g0, %pil        ! encoding: [0x91,0x97,0x80,0x00]
+        wrpr %i6,%pil
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%cwp
+        ! V9: wrpr %fp, %g0, %cwp        ! encoding: [0x93,0x97,0x80,0x00]
+        wrpr %i6,%cwp
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%cansave
+        ! V9: wrpr %fp, %g0, %cansave    ! encoding: [0x95,0x97,0x80,0x00]
+        wrpr %i6,%cansave
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%canrestore
+        ! V9: wrpr %fp, %g0, %canrestore ! encoding: [0x97,0x97,0x80,0x00]
+        wrpr %i6,%canrestore
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%cleanwin
+        ! V9: wrpr %fp, %g0, %cleanwin   ! encoding: [0x99,0x97,0x80,0x00]
+        wrpr %i6,%cleanwin
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%otherwin
+        ! V9: wrpr %fp, %g0, %otherwin   ! encoding: [0x9b,0x97,0x80,0x00]
+        wrpr %i6,%otherwin
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr %i6,%wstate
+        ! V9: wrpr %fp, %g0, %wstate     ! encoding: [0x9d,0x97,0x80,0x00]
+        wrpr %i6,%wstate
+
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tpc
+        ! V9: wrpr %g0, 255, %tpc        ! encoding: [0x81,0x90,0x20,0xff]
+        wrpr 255,%tpc
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tnpc
+        ! V9: wrpr %g0, 255, %tnpc       ! encoding: [0x83,0x90,0x20,0xff]
+        wrpr 255,%tnpc
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tstate
+        ! V9: wrpr %g0, 255, %tstate     ! encoding: [0x85,0x90,0x20,0xff]
+        wrpr 255,%tstate
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tt
+        ! V9: wrpr %g0, 255, %tt         ! encoding: [0x87,0x90,0x20,0xff]
+        wrpr 255,%tt
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tick
+        ! V9: wrpr %g0, 255, %tick       ! encoding: [0x89,0x90,0x20,0xff]
+        wrpr 255,%tick
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tba
+        ! V9: wrpr %g0, 255, %tba        ! encoding: [0x8b,0x90,0x20,0xff]
+        wrpr 255,%tba
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%pstate
+        ! V9: wrpr %g0, 255, %pstate     ! encoding: [0x8d,0x90,0x20,0xff]
+        wrpr 255,%pstate
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%tl
+        ! V9: wrpr %g0, 255, %tl         ! encoding: [0x8f,0x90,0x20,0xff]
+        wrpr 255,%tl
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%pil
+        ! V9: wrpr %g0, 255, %pil        ! encoding: [0x91,0x90,0x20,0xff]
+        wrpr 255,%pil
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%cwp
+        ! V9: wrpr %g0, 255, %cwp        ! encoding: [0x93,0x90,0x20,0xff]
+        wrpr 255,%cwp
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%cansave
+        ! V9: wrpr %g0, 255, %cansave    ! encoding: [0x95,0x90,0x20,0xff]
+        wrpr 255,%cansave
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%canrestore
+        ! V9: wrpr %g0, 255, %canrestore ! encoding: [0x97,0x90,0x20,0xff]
+        wrpr 255,%canrestore
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%cleanwin
+        ! V9: wrpr %g0, 255, %cleanwin   ! encoding: [0x99,0x90,0x20,0xff]
+        wrpr 255,%cleanwin
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%otherwin
+        ! V9: wrpr %g0, 255, %otherwin   ! encoding: [0x9b,0x90,0x20,0xff]
+        wrpr 255,%otherwin
+        ! V8:      error: instruction requires a CPU feature not currently enabled
+        ! V8-NEXT: wrpr 255,%wstate
+        ! V9: wrpr %g0, 255, %wstate     ! encoding: [0x9d,0x90,0x20,0xff]
+        wrpr 255,%wstate
+
+        ! V8:      error: instruction requires a CPU feature not currently enabled
         ! V8-NEXT: rdpr %tpc,%i5
         ! V9: rdpr %tpc, %i5            ! encoding: [0xbb,0x50,0x00,0x00]
         rdpr %tpc,%i5
         ! V8:      error: instruction requires a CPU feature not currently enabled
         ! V8-NEXT: rdpr %tnpc,%i5
         ! V9: rdpr %tnpc, %i5           ! encoding: [0xbb,0x50,0x40,0x00]
         rdpr %tnpc,%i5
         ! V8:      error: instruction requires a CPU feature not currently enabled