[AMDGPU] Fix copying a machine operand

Without this I get:

*** Bad machine code: Instruction has operand with wrong parent set ***
- function:    available_externally_test
- basic block: %bb.0  (0x7dad598)
- instruction: %0:r600_treg32_x = MOV 1, 0, 0, 0, $alu_literal_x, 0, 0, 0, -1, 1, $pred_sel_off, @available_externally, 0

Differential Revision: https://reviews.llvm.org/D111549

Author: jayfoad

llvm/lib/Target/AMDGPU/R600ISelLowering.cpp

@@ -336,7 +336,9 @@ R600TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
         *BB, MI, R600::MOV, MI.getOperand(0).getReg(), R600::ALU_LITERAL_X);
     int Idx = TII->getOperandIdx(*MIB, R600::OpName::literal);
     //TODO: Ugh this is rather ugly
-    MIB->getOperand(Idx) = MI.getOperand(1);
+    const MachineOperand &MO = MI.getOperand(1);
+    MIB->getOperand(Idx).ChangeToGA(MO.getGlobal(), MO.getOffset(),
+                                    MO.getTargetFlags());
     break;
   }
 

llvm/test/CodeGen/AMDGPU/global-constant.ll

@@ -2,7 +2,7 @@
 ; RUN: llc -mtriple=amdgcn-- -mcpu=kaveri -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
 ; RUN: llc -mtriple=amdgcn-mesa-mesa3d -mcpu=kaveri -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
 ; RUN: llc -mtriple=amdgcn--amdhsa -mcpu=kaveri -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
-; RUN: llc -mtriple=r600-- -mcpu=cypress < %s | FileCheck -check-prefix=R600 %s
+; RUN: llc -mtriple=r600-- -mcpu=cypress -verify-machineinstrs < %s | FileCheck -check-prefix=R600 %s
 
 @private1 = private unnamed_addr addrspace(4) constant [4 x float] [float 0.0, float 1.0, float 2.0, float 3.0]
 @private2 = private unnamed_addr addrspace(4) constant [4 x float] [float 4.0, float 5.0, float 6.0, float 7.0]