From dfa6293b55cf77a00e7fd36c1a61e941b4ff71d7 Mon Sep 17 00:00:00 2001
From: Bill Seurer <seurer@linux.vnet.ibm.com>
Date: Fri, 5 Dec 2014 20:15:56 +0000
Subject: [PATCH] [PowerPC]Add VSX loads/stores to fastisel for PPC target

This patch adds VSX floating point loads and stores to fastisel.

Along with the change to tablegen (D6220), VSX instructions are now fully supported in fastisel.

http://reviews.llvm.org/D6274


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223507 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCFastISel.cpp | 40 +++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/lib/Target/PowerPC/PPCFastISel.cpp b/lib/Target/PowerPC/PPCFastISel.cpp
index 11493544595..d558bb128eb 100644
--- a/lib/Target/PowerPC/PPCFastISel.cpp
+++ b/lib/Target/PowerPC/PPCFastISel.cpp
@@ -139,6 +139,9 @@ class PPCFastISel final : public FastISel {
   private:
     bool isTypeLegal(Type *Ty, MVT &VT);
     bool isLoadTypeLegal(Type *Ty, MVT &VT);
+    bool isVSFRCRegister(unsigned Register) const {
+      return MRI.getRegClass(Register)->getID() == PPC::VSFRCRegClassID;
+    }
     bool PPCEmitCmp(const Value *Src1Value, const Value *Src2Value,
                     bool isZExt, unsigned DestReg);
     bool PPCEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
@@ -482,6 +485,16 @@ bool PPCFastISel::PPCEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
   // the indexed form.  Also handle stack pointers with special needs.
   unsigned IndexReg = 0;
   PPCSimplifyAddress(Addr, VT, UseOffset, IndexReg);
+
+  // If this is a potential VSX load with an offset of 0, a VSX indexed load can
+  // be used.
+  bool IsVSFRC = (ResultReg != 0) && isVSFRCRegister(ResultReg);
+  if (IsVSFRC && (Opc == PPC::LFD) && 
+      (Addr.BaseType != Address::FrameIndexBase) && UseOffset &&
+      (Addr.Offset == 0)) {
+    UseOffset = false;
+  }
+
   if (ResultReg == 0)
     ResultReg = createResultReg(UseRC);
 
@@ -489,6 +502,8 @@ bool PPCFastISel::PPCEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
   // in range, as otherwise PPCSimplifyAddress would have converted it
   // into a RegBase.
   if (Addr.BaseType == Address::FrameIndexBase) {
+    // VSX only provides an indexed load.
+    if (IsVSFRC && Opc == PPC::LFD) return false;
 
     MachineMemOperand *MMO =
       FuncInfo.MF->getMachineMemOperand(
@@ -501,6 +516,8 @@ bool PPCFastISel::PPCEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
 
   // Base reg with offset in range.
   } else if (UseOffset) {
+    // VSX only provides an indexed load.
+    if (IsVSFRC && Opc == PPC::LFD) return false;
 
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
       .addImm(Addr.Offset).addReg(Addr.Base.Reg);
@@ -524,7 +541,7 @@ bool PPCFastISel::PPCEmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
       case PPC::LWA_32: Opc = PPC::LWAX_32; break;
       case PPC::LD:     Opc = PPC::LDX;     break;
       case PPC::LFS:    Opc = PPC::LFSX;    break;
-      case PPC::LFD:    Opc = PPC::LFDX;    break;
+      case PPC::LFD:    Opc = IsVSFRC ? PPC::LXSDX : PPC::LFDX; break;
     }
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
       .addReg(Addr.Base.Reg).addReg(IndexReg);
@@ -602,10 +619,22 @@ bool PPCFastISel::PPCEmitStore(MVT VT, unsigned SrcReg, Address &Addr) {
   unsigned IndexReg = 0;
   PPCSimplifyAddress(Addr, VT, UseOffset, IndexReg);
 
+  // If this is a potential VSX store with an offset of 0, a VSX indexed store
+  // can be used.
+  bool IsVSFRC = isVSFRCRegister(SrcReg);
+  if (IsVSFRC && (Opc == PPC::STFD) && 
+      (Addr.BaseType != Address::FrameIndexBase) && UseOffset && 
+      (Addr.Offset == 0)) {
+    UseOffset = false;
+  }
+
   // Note: If we still have a frame index here, we know the offset is
   // in range, as otherwise PPCSimplifyAddress would have converted it
   // into a RegBase.
   if (Addr.BaseType == Address::FrameIndexBase) {
+    // VSX only provides an indexed store.
+    if (IsVSFRC && Opc == PPC::STFD) return false;
+
     MachineMemOperand *MMO =
       FuncInfo.MF->getMachineMemOperand(
         MachinePointerInfo::getFixedStack(Addr.Base.FI, Addr.Offset),
@@ -619,12 +648,15 @@ bool PPCFastISel::PPCEmitStore(MVT VT, unsigned SrcReg, Address &Addr) {
         .addMemOperand(MMO);
 
   // Base reg with offset in range.
-  } else if (UseOffset)
+  } else if (UseOffset) {
+    // VSX only provides an indexed store.
+    if (IsVSFRC && Opc == PPC::STFD) return false;
+    
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc))
       .addReg(SrcReg).addImm(Addr.Offset).addReg(Addr.Base.Reg);
 
   // Indexed form.
-  else {
+  } else {
     // Get the RR opcode corresponding to the RI one.  FIXME: It would be
     // preferable to use the ImmToIdxMap from PPCRegisterInfo.cpp, but it
     // is hard to get at.
@@ -638,7 +670,7 @@ bool PPCFastISel::PPCEmitStore(MVT VT, unsigned SrcReg, Address &Addr) {
       case PPC::STW8: Opc = PPC::STWX8; break;
       case PPC::STD:  Opc = PPC::STDX;  break;
       case PPC::STFS: Opc = PPC::STFSX; break;
-      case PPC::STFD: Opc = PPC::STFDX; break;
+      case PPC::STFD: Opc = IsVSFRC ? PPC::STXSDX : PPC::STFDX; break;
     }
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc))
       .addReg(SrcReg).addReg(Addr.Base.Reg).addReg(IndexReg);