From 60c8fa6bb9db791acf6846fe250c184e3f1df168 Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Tue, 7 Feb 2012 23:56:08 +0000
Subject: [PATCH] [fast-isel] Add support for indirect branches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150014 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMFastISel.cpp           | 13 +++++++++++++
 test/CodeGen/ARM/fast-isel-indirectbr.ll | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 test/CodeGen/ARM/fast-isel-indirectbr.ll

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 904e9171c87..d2c8d15dbbb 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -157,6 +157,7 @@ class ARMFastISel : public FastISel {
     bool SelectLoad(const Instruction *I);
     bool SelectStore(const Instruction *I);
     bool SelectBranch(const Instruction *I);
+    bool SelectIndirectBr(const Instruction *I);
     bool SelectCmp(const Instruction *I);
     bool SelectFPExt(const Instruction *I);
     bool SelectFPTrunc(const Instruction *I);
@@ -1350,6 +1351,16 @@ bool ARMFastISel::SelectBranch(const Instruction *I) {
   return true;
 }
 
+bool ARMFastISel::SelectIndirectBr(const Instruction *I) {
+  unsigned AddrReg = getRegForValue(I->getOperand(0));
+  if (AddrReg == 0) return false;
+
+  unsigned Opc = isThumb2 ? ARM::tBRIND : ARM::BX;
+  AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc))
+                  .addReg(AddrReg));
+  return true;  
+}
+
 bool ARMFastISel::ARMEmitCmp(const Value *Src1Value, const Value *Src2Value,
                              bool isZExt) {
   Type *Ty = Src1Value->getType();
@@ -2468,6 +2479,8 @@ bool ARMFastISel::TargetSelectInstruction(const Instruction *I) {
       return SelectStore(I);
     case Instruction::Br:
       return SelectBranch(I);
+    case Instruction::IndirectBr:
+      return SelectIndirectBr(I);
     case Instruction::ICmp:
     case Instruction::FCmp:
       return SelectCmp(I);
diff --git a/test/CodeGen/ARM/fast-isel-indirectbr.ll b/test/CodeGen/ARM/fast-isel-indirectbr.ll
new file mode 100644
index 00000000000..be8035ec794
--- /dev/null
+++ b/test/CodeGen/ARM/fast-isel-indirectbr.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios | FileCheck %s --check-prefix=ARM
+; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios | FileCheck %s --check-prefix=THUMB
+
+define void @t1(i8* %x) {
+entry:
+; ARM: t1
+; THUMB: t1
+  br label %L0
+
+L0:
+  br label %L1
+
+L1:
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+; ARM: bx r0
+; THUMB: mov pc, r0
+}