From 2684c5db84479456b2ff8264df6f414c9d240fa1 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Mon, 4 Apr 2011 17:07:06 +0000
Subject: [PATCH] Use X0 instead of R0 for the zero register on ppc64.

The 32-bit R0 cannot be used where a 64-bit register is expected.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128828 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCISelLowering.cpp | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 70d00e4b5cc..40c007eaf96 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -899,7 +899,8 @@ bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
     short Imm;
     if (isIntS16Immediate(CN, Imm)) {
       Disp = DAG.getTargetConstant(Imm, CN->getValueType(0));
-      Base = DAG.getRegister(PPC::R0, CN->getValueType(0));
+      Base = DAG.getRegister(PPCSubTarget.isPPC64() ? PPC::X0 : PPC::R0,
+                             CN->getValueType(0));
       return true;
     }
 
@@ -947,7 +948,8 @@ bool PPCTargetLowering::SelectAddressRegRegOnly(SDValue N, SDValue &Base,
   }
 
   // Otherwise, do it the hard way, using R0 as the base register.
-  Base = DAG.getRegister(PPC::R0, N.getValueType());
+  Base = DAG.getRegister(PPCSubTarget.isPPC64() ? PPC::X0 : PPC::R0,
+                         N.getValueType());
   Index = N;
   return true;
 }
@@ -4571,6 +4573,7 @@ PPCTargetLowering::EmitPartwordAtomicBinary(MachineInstr *MI,
   // registers without caring whether they're 32 or 64, but here we're
   // doing actual arithmetic on the addresses.
   bool is64bit = PPCSubTarget.isPPC64();
+  unsigned ZeroReg = is64bit ? PPC::X0 : PPC::R0;
 
   const BasicBlock *LLVM_BB = BB->getBasicBlock();
   MachineFunction *F = BB->getParent();
@@ -4634,8 +4637,7 @@ PPCTargetLowering::EmitPartwordAtomicBinary(MachineInstr *MI,
   //   bne- loopMBB
   //   fallthrough --> exitMBB
   //   srw dest, tmpDest, shift
-
-  if (ptrA!=PPC::R0) {
+  if (ptrA != ZeroReg) {
     Ptr1Reg = RegInfo.createVirtualRegister(RC);
     BuildMI(BB, dl, TII->get(is64bit ? PPC::ADD8 : PPC::ADD4), Ptr1Reg)
       .addReg(ptrA).addReg(ptrB);
@@ -4665,7 +4667,7 @@ PPCTargetLowering::EmitPartwordAtomicBinary(MachineInstr *MI,
 
   BB = loopMBB;
   BuildMI(BB, dl, TII->get(PPC::LWARX), TmpDestReg)
-    .addReg(PPC::R0).addReg(PtrReg);
+    .addReg(ZeroReg).addReg(PtrReg);
   if (BinOpcode)
     BuildMI(BB, dl, TII->get(BinOpcode), TmpReg)
       .addReg(Incr2Reg).addReg(TmpDestReg);
@@ -4676,7 +4678,7 @@ PPCTargetLowering::EmitPartwordAtomicBinary(MachineInstr *MI,
   BuildMI(BB, dl, TII->get(is64bit ? PPC::OR8 : PPC::OR), Tmp4Reg)
     .addReg(Tmp3Reg).addReg(Tmp2Reg);
   BuildMI(BB, dl, TII->get(PPC::STWCX))
-    .addReg(Tmp4Reg).addReg(PPC::R0).addReg(PtrReg);
+    .addReg(Tmp4Reg).addReg(ZeroReg).addReg(PtrReg);
   BuildMI(BB, dl, TII->get(PPC::BCC))
     .addImm(PPC::PRED_NE).addReg(PPC::CR0).addMBB(loopMBB);
   BB->addSuccessor(loopMBB);
@@ -4933,6 +4935,7 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     unsigned TmpDestReg = RegInfo.createVirtualRegister(RC);
     unsigned Ptr1Reg;
     unsigned TmpReg = RegInfo.createVirtualRegister(RC);
+    unsigned ZeroReg = is64bit ? PPC::X0 : PPC::R0;
     //  thisMBB:
     //   ...
     //   fallthrough --> loopMBB
@@ -4965,7 +4968,7 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     //   stwcx. tmpDest, ptr
     // exitBB:
     //   srw dest, tmpDest, shift
-    if (ptrA!=PPC::R0) {
+    if (ptrA != ZeroReg) {
       Ptr1Reg = RegInfo.createVirtualRegister(RC);
       BuildMI(BB, dl, TII->get(is64bit ? PPC::ADD8 : PPC::ADD4), Ptr1Reg)
         .addReg(ptrA).addReg(ptrB);
@@ -5002,7 +5005,7 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
 
     BB = loop1MBB;
     BuildMI(BB, dl, TII->get(PPC::LWARX), TmpDestReg)
-        .addReg(PPC::R0).addReg(PtrReg);
+        .addReg(ZeroReg).addReg(PtrReg);
     BuildMI(BB, dl, TII->get(PPC::AND),TmpReg)
         .addReg(TmpDestReg).addReg(MaskReg);
     BuildMI(BB, dl, TII->get(PPC::CMPW), PPC::CR0)
@@ -5018,7 +5021,7 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     BuildMI(BB, dl, TII->get(PPC::OR),Tmp4Reg)
         .addReg(Tmp2Reg).addReg(NewVal3Reg);
     BuildMI(BB, dl, TII->get(PPC::STWCX)).addReg(Tmp4Reg)
-        .addReg(PPC::R0).addReg(PtrReg);
+        .addReg(ZeroReg).addReg(PtrReg);
     BuildMI(BB, dl, TII->get(PPC::BCC))
       .addImm(PPC::PRED_NE).addReg(PPC::CR0).addMBB(loop1MBB);
     BuildMI(BB, dl, TII->get(PPC::B)).addMBB(exitMBB);
@@ -5027,7 +5030,7 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
 
     BB = midMBB;
     BuildMI(BB, dl, TII->get(PPC::STWCX)).addReg(TmpDestReg)
-      .addReg(PPC::R0).addReg(PtrReg);
+      .addReg(ZeroReg).addReg(PtrReg);
     BB->addSuccessor(exitMBB);
 
     //  exitMBB:
-- 
2.34.1