From 816f6d0ac76c0ffb2ea9ecb72349d5d7d0fa8d1a Mon Sep 17 00:00:00 2001
From: Michael Liao <michael.liao@intel.com>
Date: Thu, 28 Mar 2013 23:13:21 +0000
Subject: [PATCH] Skip moving call address loading into callseq when targets
 prefer register indirect call.

To enable a load of a call address to be folded with that call, this
load is moved from outside of callseq into callseq. Such a moving
adds a non-glued node (that load) into a glued sequence. This non-glue
load is only removed when DAG selection folds them into a memory form
call instruction. When such instruction selection is disabled, it breaks
DAG schedule.

To prevent that, such moving is disabled when target favors register
indirect call.

Previous workaround disabling CALL32m/CALL64m insn selection is removed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178308 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelDAGToDAG.cpp |  4 +++-
 lib/Target/X86/X86ISelLowering.cpp | 13 -------------
 lib/Target/X86/X86InstrControl.td  |  5 +++--
 lib/Target/X86/X86InstrInfo.td     |  1 +
 4 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 00fbe6924cc..6041669f818 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -444,7 +444,9 @@ void X86DAGToDAGISel::PreprocessISelDAG() {
     SDNode *N = I++;  // Preincrement iterator to avoid invalidation issues.
 
     if (OptLevel != CodeGenOpt::None &&
-        (N->getOpcode() == X86ISD::CALL ||
+        // Only does this when target favors doesn't favor register indirect
+        // call.
+        ((N->getOpcode() == X86ISD::CALL && !Subtarget->callRegIndirect()) ||
          (N->getOpcode() == X86ISD::TC_RETURN &&
           // Only does this if load can be folded into TC_RETURN.
           (Subtarget->is64Bit() ||
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bff5426f908..709e9e8aaee 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2634,19 +2634,6 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     InFlag = Chain.getValue(1);
   }
 
-  // Use indirect reference through register, when CALL uses a memory reference.
-  if (Subtarget->callRegIndirect() &&
-      Callee.getOpcode() == ISD::LOAD) {
-    const TargetRegisterClass *AddrRegClass =
-      getRegClassFor(Subtarget->is64Bit() ? MVT::i64:MVT::i32);
-    MachineRegisterInfo &MRI = MF.getRegInfo();
-    unsigned VReg = MRI.createVirtualRegister(AddrRegClass);
-    SDValue tempValue = DAG.getCopyFromReg(Callee,
-                                           dl, VReg, Callee.getValueType());
-    Chain = DAG.getCopyToReg(Chain, dl, VReg, tempValue, InFlag);
-    InFlag = Chain.getValue(1);
-  }
-
   Ops.push_back(Chain);
   Ops.push_back(Callee);
 
diff --git a/lib/Target/X86/X86InstrControl.td b/lib/Target/X86/X86InstrControl.td
index 1027dedcec4..0e696513d47 100644
--- a/lib/Target/X86/X86InstrControl.td
+++ b/lib/Target/X86/X86InstrControl.td
@@ -170,7 +170,8 @@ let isCall = 1 in
     def CALL32m     : I<0xFF, MRM2m, (outs), (ins i32mem:$dst),
                         "call{l}\t{*}$dst", [(X86call (loadi32 addr:$dst))],
                         IIC_CALL_MEM>,
-                      Requires<[In32BitMode]>, Sched<[WriteJumpLd]>;
+                      Requires<[In32BitMode,FavorMemIndirectCall]>,
+                      Sched<[WriteJumpLd]>;
 
     def FARCALL16i  : Iseg16<0x9A, RawFrmImm16, (outs),
                              (ins i16imm:$off, i16imm:$seg),
@@ -245,7 +246,7 @@ let isCall = 1, Uses = [RSP], SchedRW = [WriteJump] in {
   def CALL64m       : I<0xFF, MRM2m, (outs), (ins i64mem:$dst),
                         "call{q}\t{*}$dst", [(X86call (loadi64 addr:$dst))],
                         IIC_CALL_MEM>,
-                      Requires<[In64BitMode]>;
+                      Requires<[In64BitMode,FavorMemIndirectCall]>;
 
   def FARCALL64   : RI<0xFF, MRM3m, (outs), (ins opaque80mem:$dst),
                        "lcall{q}\t{*}$dst", [], IIC_CALL_FAR_MEM>;
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 359c507d472..93e8beb19be 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -630,6 +630,7 @@ def OptForSize   : Predicate<"OptForSize">;
 def OptForSpeed  : Predicate<"!OptForSize">;
 def FastBTMem    : Predicate<"!Subtarget->isBTMemSlow()">;
 def CallImmAddr  : Predicate<"Subtarget->IsLegalToCallImmediateAddr(TM)">;
+def FavorMemIndirectCall  : Predicate<"!Subtarget->callRegIndirect()">;
 
 //===----------------------------------------------------------------------===//
 // X86 Instruction Format Definitions.
-- 
2.34.1