[mips] Implement the following optimizations using dominance information to

make PIC calls a little more efficient:

1. Remove instructions setting up $gp if it is known that a function has been
   called at least once.
2. Save the address of a called function in a register instead of loading
   it from the GOT at every call site.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195892 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 8 deletions

diff --git a/lib/Target/Mips/MipsSEISelLowering.cpp b/lib/Target/Mips/MipsSEISelLowering.cpp
index 809adc03b1..cc6411fd88 100644
--- a/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -1077,14 +1077,7 @@ getOpndList(SmallVectorImpl<SDValue> &Ops,
             std::deque< std::pair<unsigned, SDValue> > &RegsToPass,
             bool IsPICCall, bool GlobalOrExternal, bool InternalLinkage,
             CallLoweringInfo &CLI, SDValue Callee, SDValue Chain) const {
-  // T9 should contain the address of the callee function if
-  // -reloction-model=pic or it is an indirect call.
-  if (IsPICCall || !GlobalOrExternal) {
-    unsigned T9Reg = IsN64 ? Mips::T9_64 : Mips::T9;
-    RegsToPass.push_front(std::make_pair(T9Reg, Callee));
-  } else
-    Ops.push_back(Callee);
-
+  Ops.push_back(Callee);
   MipsTargetLowering::getOpndList(Ops, RegsToPass, IsPICCall, GlobalOrExternal,
                                   InternalLinkage, CLI, Callee, Chain);
 }