[GlobalISel][X86] G_GEP selection support.

Summary: [GlobalISel][X86] G_GEP selection support.

Reviewers: zvi, guyblank

Reviewed By: guyblank

Subscribers: dberris, rovka, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D32396

llvm-svn: 302412

2 files changed, 33 insertions, 10 deletions

diff --git a/llvm/lib/Target/X86/X86InstructionSelector.cpp b/llvm/lib/Target/X86/X86InstructionSelector.cpp
index 38f7bc0af5c..d65eb1de8d0 100644
--- a/llvm/lib/Target/X86/X86InstructionSelector.cpp
+++ b/llvm/lib/Target/X86/X86InstructionSelector.cpp
@@ -65,8 +65,8 @@ private:
                       MachineFunction &MF) const;
   bool selectLoadStoreOp(MachineInstr &I, MachineRegisterInfo &MRI,
                          MachineFunction &MF) const;
-  bool selectFrameIndex(MachineInstr &I, MachineRegisterInfo &MRI,
-                        MachineFunction &MF) const;
+  bool selectFrameIndexOrGep(MachineInstr &I, MachineRegisterInfo &MRI,
+                             MachineFunction &MF) const;
   bool selectConstant(MachineInstr &I, MachineRegisterInfo &MRI,
                       MachineFunction &MF) const;
   bool selectTrunc(MachineInstr &I, MachineRegisterInfo &MRI,
@@ -235,7 +235,7 @@ bool X86InstructionSelector::select(MachineInstr &I) const {
     return true;
   if (selectLoadStoreOp(I, MRI, MF))
     return true;
-  if (selectFrameIndex(I, MRI, MF))
+  if (selectFrameIndexOrGep(I, MRI, MF))
     return true;
   if (selectConstant(I, MRI, MF))
     return true;
@@ -427,27 +427,37 @@ bool X86InstructionSelector::selectLoadStoreOp(MachineInstr &I,
   return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
 }
 
-bool X86InstructionSelector::selectFrameIndex(MachineInstr &I,
-                                              MachineRegisterInfo &MRI,
-                                              MachineFunction &MF) const {
-  if (I.getOpcode() != TargetOpcode::G_FRAME_INDEX)
+bool X86InstructionSelector::selectFrameIndexOrGep(MachineInstr &I,
+                                                   MachineRegisterInfo &MRI,
+                                                   MachineFunction &MF) const {
+  unsigned Opc = I.getOpcode();
+
+  if (Opc != TargetOpcode::G_FRAME_INDEX && Opc != TargetOpcode::G_GEP)
     return false;
 
   const unsigned DefReg = I.getOperand(0).getReg();
   LLT Ty = MRI.getType(DefReg);
 
-  // Use LEA to calculate frame index.
+  // Use LEA to calculate frame index and GEP
   unsigned NewOpc;
   if (Ty == LLT::pointer(0, 64))
     NewOpc = X86::LEA64r;
   else if (Ty == LLT::pointer(0, 32))
     NewOpc = STI.isTarget64BitILP32() ? X86::LEA64_32r : X86::LEA32r;
   else
-    llvm_unreachable("Can't select G_FRAME_INDEX, unsupported type.");
+    llvm_unreachable("Can't select G_FRAME_INDEX/G_GEP, unsupported type.");
 
   I.setDesc(TII.get(NewOpc));
   MachineInstrBuilder MIB(MF, I);
-  addOffset(MIB, 0);
+
+  if (Opc == TargetOpcode::G_FRAME_INDEX) {
+    addOffset(MIB, 0);
+  } else {
+    MachineOperand &InxOp = I.getOperand(2);
+    I.addOperand(InxOp);        // set IndexReg
+    InxOp.ChangeToImmediate(1); // set Scale
+    MIB.addImm(0).addReg(0);
+  }
 
   return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
 }
diff --git a/llvm/lib/Target/X86/X86LegalizerInfo.cpp b/llvm/lib/Target/X86/X86LegalizerInfo.cpp
index ae123c6349a..4f5e70414aa 100644
--- a/llvm/lib/Target/X86/X86LegalizerInfo.cpp
+++ b/llvm/lib/Target/X86/X86LegalizerInfo.cpp
@@ -70,6 +70,12 @@ void X86LegalizerInfo::setLegalizerInfo32bit() {
   // Pointer-handling
   setAction({G_FRAME_INDEX, p0}, Legal);
 
+  setAction({G_GEP, p0}, Legal);
+  setAction({G_GEP, 1, s32}, Legal);
+
+  for (auto Ty : {s1, s8, s16})
+    setAction({G_GEP, 1, Ty}, WidenScalar);
+
   // Constants
   for (auto Ty : {s8, s16, s32, p0})
     setAction({TargetOpcode::G_CONSTANT, Ty}, Legal);
@@ -114,6 +120,13 @@ void X86LegalizerInfo::setLegalizerInfo64bit() {
   // Pointer-handling
   setAction({G_FRAME_INDEX, p0}, Legal);
 
+  setAction({G_GEP, p0}, Legal);
+  setAction({G_GEP, 1, s32}, Legal);
+  setAction({G_GEP, 1, s64}, Legal);
+
+  for (auto Ty : {s1, s8, s16})
+    setAction({G_GEP, 1, Ty}, WidenScalar);
+
   // Constants
   for (auto Ty : {s8, s16, s32, s64, p0})
     setAction({TargetOpcode::G_CONSTANT, Ty}, Legal);