[PowerPC][GISel] Select sync instructions required by atomic operations

[lkail]

Summary

This is part of selecting G_ATOMIC* instructions. Select isync, sync and lwsync in GISel.

[arsenm]

llvm/lib/Target/PowerPC/GISel/PPCInstructionSelector.cpp

725 ↗

(On Diff #487712)

These should be trivially auto-selected from tablegen

[lkail]

@arsenm Much appreciated for the suggestion.

[tschuett]

llvm/lib/Target/PowerPC/GISel/PPCRegisterBankInfo.cpp

179

compute value

179

check every operand

llvm/lib/Target/PowerPC/GISel/PPCRegisterBankInfo.cpp

if (onlyDefinesFP(*DefMI, MRI, TRI))
           {getValueMapping(Size == 64 ? PMI_FPR64 : PMI_FPR32),
            getValueMapping(PMI_GPR64)});
     else
       OperandsMapping = getOperandsMapping(
           {getValueMapping(Size == 64 ? PMI_GPR64 : PMI_GPR32),
            getValueMapping(PMI_GPR64)});
     break;
   }
+  case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS: {
+    // FIXME: We have to check every operand in this MI and compute value
+    // mapping accordingly.
+    SmallVector<const ValueMapping *, 8> OpdsMapping(NumOperands);
+    OperandsMapping = getOperandsMapping(OpdsMapping);
+    break;
+  }
   default:
     return getInvalidInstructionMapping();
   }
 
   return getInstructionMapping(MappingID, Cost, OperandsMapping, NumOperands);
 }
 
 /// Returns whether opcode \p Opc is a pre-isel generic floating-point opcode,

llvm/test/CodeGen/PowerPC/GlobalISel/ppc-isel-sync.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le -global-isel \
+; RUN:   -ppc-asm-full-reg-names < %s | FileCheck %s
+
+declare void @llvm.ppc.isync()
+declare void @llvm.ppc.sync()
+declare void @llvm.ppc.lwsync()
+
+define void @test_sync() {
+; CHECK-LABEL: test_sync:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    isync
+; CHECK-NEXT:    sync
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:    blr
+entry:
+  call void @llvm.ppc.isync()
+  call void @llvm.ppc.sync()
+  call void @llvm.ppc.lwsync()
+  ret void
+}