[GlobalISel] Add support for indirectbr

Differential Revision: https://reviews.llvm.org/D28079

llvm-svn: 293470

4 files changed, 25 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 1a667d60166..58bd65ef323 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -252,6 +252,21 @@ bool IRTranslator::translateSwitch(const User &U,
   return true;
 }
 
+bool IRTranslator::translateIndirectBr(const User &U,
+                                       MachineIRBuilder &MIRBuilder) {
+  const IndirectBrInst &BrInst = cast<IndirectBrInst>(U);
+
+  const unsigned Tgt = getOrCreateVReg(*BrInst.getAddress());
+  MIRBuilder.buildBrIndirect(Tgt);
+
+  // Link successors.
+  MachineBasicBlock &CurBB = MIRBuilder.getMBB();
+  for (const BasicBlock *Succ : BrInst.successors())
+    CurBB.addSuccessor(&getOrCreateBB(*Succ));
+
+  return true;
+}
+
 bool IRTranslator::translateLoad(const User &U, MachineIRBuilder &MIRBuilder) {
   const LoadInst &LI = cast<LoadInst>(U);
 
diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index ae1550d0d3d..01457260ca6 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -217,6 +217,10 @@ MachineInstrBuilder MachineIRBuilder::buildBr(MachineBasicBlock &Dest) {
   return buildInstr(TargetOpcode::G_BR).addMBB(&Dest);
 }
 
+MachineInstrBuilder MachineIRBuilder::buildBrIndirect(unsigned Tgt) {
+  return buildInstr(TargetOpcode::G_BRINDIRECT).addUse(Tgt);
+}
+
 MachineInstrBuilder MachineIRBuilder::buildCopy(unsigned Res, unsigned Op) {
   return buildInstr(TargetOpcode::COPY).addDef(Res).addUse(Op);
 }
diff --git a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
index 5c03ea930af..21d80ca9f81 100644
--- a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
@@ -525,6 +525,11 @@ bool AArch64InstructionSelector::select(MachineInstr &I) const {
     return constrainSelectedInstRegOperands(*MIB.getInstr(), TII, TRI, RBI);
   }
 
+  case TargetOpcode::G_BRINDIRECT: {
+    I.setDesc(TII.get(AArch64::BR));
+    return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
+  }
+
   case TargetOpcode::G_FCONSTANT:
   case TargetOpcode::G_CONSTANT: {
     const bool isFP = Opcode == TargetOpcode::G_FCONSTANT;
diff --git a/llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp
index 9d774f6b282..86037c97731 100644
--- a/llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp
@@ -167,6 +167,7 @@ AArch64LegalizerInfo::AArch64LegalizerInfo() {
   // Control-flow
   for (auto Ty : {s1, s8, s16, s32})
     setAction({G_BRCOND, Ty}, Legal);
+  setAction({G_BRINDIRECT, p0}, Legal);
 
   // Select
   for (auto Ty : {s1, s8, s16, s32, s64, p0})