add another target hook for branch folding.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31262 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index e89493bff3..f34f00a32f 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -420,6 +420,18 @@ void X86InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
   BuildMI(&MBB, X86::JMP, 1).addMBB(FBB);
 }
 
+bool X86InstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
+  if (MBB.empty()) return false;
+  
+  switch (MBB.back().getOpcode()) {
+  case X86::JMP:     // Uncond branch.
+  case X86::JMP32r:  // Indirect branch.
+  case X86::JMP32m:  // Indirect branch through mem.
+    return true;
+  default: return false;
+  }
+}
+
 bool X86InstrInfo::
 ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
   assert(Cond.size() == 1 && "Invalid X86 branch condition!");