[llvm] [X86][GlobalISel] Support addr matching in SDAG patterns (PR #130445)

[Simon Pilgrim via llvm-commits]

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@@ -530,30 +546,75 @@ unsigned X86InstructionSelector::getLoadStoreOp(const LLT &Ty,
 }
 
 // Fill in an address from the given instruction.
-static void X86SelectAddress(const MachineInstr &I,
+static bool X86SelectAddress(MachineInstr &I, const X86TargetMachine &TM,
                              const MachineRegisterInfo &MRI,
-                             X86AddressMode &AM) {
-  assert(I.getOperand(0).isReg() && "unsupported opperand.");
+                             const X86Subtarget &STI, X86AddressMode &AM) {
+  assert(I.getOperand(0).isReg() && "unsupported operand.");
   assert(MRI.getType(I.getOperand(0).getReg()).isPointer() &&
          "unsupported type.");
 
-  if (I.getOpcode() == TargetOpcode::G_PTR_ADD) {
+  switch (I.getOpcode()) {
+  default:
+    break;
+  case TargetOpcode::G_FRAME_INDEX:
+    AM.Base.FrameIndex = I.getOperand(1).getIndex();
+    AM.BaseType = X86AddressMode::FrameIndexBase;
+    return true;
+  case TargetOpcode::G_PTR_ADD: {
     if (auto COff = getIConstantVRegSExtVal(I.getOperand(2).getReg(), MRI)) {
       int64_t Imm = *COff;
       if (isInt<32>(Imm)) { // Check for displacement overflow.
         AM.Disp = static_cast<int32_t>(Imm);
         AM.Base.Reg = I.getOperand(1).getReg();
-        return;
+        return true;
       }
     }
-  } else if (I.getOpcode() == TargetOpcode::G_FRAME_INDEX) {
-    AM.Base.FrameIndex = I.getOperand(1).getIndex();
-    AM.BaseType = X86AddressMode::FrameIndexBase;
-    return;
+    break;
   }
+  case TargetOpcode::G_GLOBAL_VALUE: {
+    auto GV = I.getOperand(1).getGlobal();
+    if (GV->isThreadLocal()) {
+      return false; // TODO: we don't support TLS yet.
+    }
+    // Can't handle alternate code models yet.
+    if (TM.getCodeModel() != CodeModel::Small)
+      return false;
+    AM.GV = GV;
+    AM.GVOpFlags = STI.classifyGlobalReference(GV);
+
+    // TODO: The ABI requires an extra load. not supported yet.
+    if (isGlobalStubReference(AM.GVOpFlags))
+      return false;
 
+    // TODO: This reference is relative to the pic base. not supported yet.
+    if (isGlobalRelativeToPICBase(AM.GVOpFlags))
+      return false;
+
+    if (STI.isPICStyleRIPRel()) {
+      // Use rip-relative addressing.
+      assert(AM.Base.Reg == 0 && AM.IndexReg == 0);
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RKSimon wrote:

(style) assert message

https://github.com/llvm/llvm-project/pull/130445