remove checks for using reserved register since there is no such restrictions listed in the doc.

Author: lei137

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -17383,8 +17383,8 @@ Register PPCTargetLowering::getRegisterByName(const char *RegName, LLT VT,
     report_fatal_error(
         Twine("Invalid global name register \"" + StringRef(RegName) + "\"."));
 
-  // FIXME: These registers are not flagged as reserved and we can generate
-  // code for `-O0` but not for `-O2`.  Need followup investigation as to why.
+  // FIXME: Unable to generate code for `-O2` but okay for `-O0`.
+  // Need followup investigation as to why.
   if ((IsPPC64 && Reg == PPC::R2) || Reg == PPC::R0)
     report_fatal_error(Twine("Trying to reserve an invalid register \"" +
                              StringRef(RegName) + "\"."));
@@ -17393,9 +17393,6 @@ Register PPCTargetLowering::getRegisterByName(const char *RegName, LLT VT,
   if (Is64Bit && StringRef(RegName).starts_with_insensitive("r"))
     Reg = Reg.id() - PPC::R0 + PPC::X0;
 
-  if (Subtarget.getRegisterInfo()->getReservedRegs(MF).test(Reg))
-    report_fatal_error(Twine("Trying to obtain a reserved register \"" +
-                             StringRef(RegName) + "\"."));
   return Reg;
 }
 

llvm/test/CodeGen/PowerPC/named-reg-alloc-r0.ll

@@ -1,5 +1,5 @@
-; RUN: not --crash llc -O0 < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
-; RUN: not --crash llc -O0 < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: not --crash llc < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 
 define i32 @get_reg() nounwind {
 entry:

llvm/test/CodeGen/PowerPC/named-reg-alloc-r1-64.ll

@@ -1,10 +1,12 @@
-; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 
 define i64 @get_reg() nounwind {
-; CHECK: Trying to obtain a reserved register "r1".
 entry:
   %reg = call i64 @llvm.read_register.i64(metadata !0)
   ret i64 %reg
+
+; CHECK-LABEL: get_reg
+; CHECK: mr 3, 1
 }
 
 declare i64 @llvm.read_register.i64(metadata) nounwind

llvm/test/CodeGen/PowerPC/named-reg-alloc-r1.ll

@@ -1,11 +1,14 @@
-; RUN: not --crash llc < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
-; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 
 define i32 @get_reg() nounwind {
-; CHECK: Trying to obtain a reserved register "r1".
 entry:
   %reg = call i32 @llvm.read_register.i32(metadata !0)
   ret i32 %reg
+
+; CHECK-LABEL: @get_reg
+; CHECK: mr 3, 1
+
 }
 
 declare i32 @llvm.read_register.i32(metadata) nounwind

llvm/test/CodeGen/PowerPC/named-reg-alloc-r13-64.ll

@@ -1,10 +1,13 @@
-; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 
 define i64 @get_reg() nounwind {
-; CHECK: Trying to obtain a reserved register "r13".
 entry:
   %reg = call i64 @llvm.read_register.i64(metadata !0)
   ret i64 %reg
+
+; CHECK-LABEL: @get_reg
+; CHECK: mr 3, 13
+
 }
 
 declare i64 @llvm.read_register.i64(metadata) nounwind

llvm/test/CodeGen/PowerPC/named-reg-alloc-r13.ll

@@ -1,11 +1,13 @@
-; RUN: not --crash llc < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
-; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s
 
 define i32 @get_reg() nounwind {
-; CHECK: Trying to obtain a reserved register "r13".
 entry:
         %reg = call i32 @llvm.read_register.i32(metadata !0)
   ret i32 %reg
+
+; CHECK-LABEL: @get_reg
+; CHECK: mr 3, 13
 }
 
 declare i32 @llvm.read_register.i32(metadata) nounwind

llvm/test/CodeGen/PowerPC/named-reg-alloc-r2.ll

@@ -1,12 +1,13 @@
-; RUN: not --crash llc < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc-unknown-linux-gnu 2>&1 | FileCheck %s
 ; RUN: not --crash llc < %s -mtriple=powerpc64-unknown-linux-gnu 2>&1 | FileCheck %s --check-prefix=CHECK-NOTPPC32
 
 define i32 @get_reg() nounwind {
 entry:
 ; CHECK-NOTPPC32: Trying to reserve an invalid register "r2".
-; CHECK: Trying to obtain a reserved register "r2".
         %reg = call i32 @llvm.read_register.i32(metadata !0)
   ret i32 %reg
+; CHECK-LABEL: @get_reg
+; CHECK: mr 3, 2
 }
 
 declare i32 @llvm.read_register.i32(metadata) nounwind