[X32][CET] Fix handling of indirect branches

[hvdijk]

Summary

As X32 uses 32-bit pointers without having 32-bit indirect branch instructions, we need to fix up indirect branches by extending the branch targets to 64 bits. This was already done for BRIND but not yet for NT_BRIND. The same logic works for both, so this applies that existing logic to NT_BRIND as well.

[MaskRay]

LGTM.

llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

case Intrinsic::x86_tilestored64: {
         CNode = CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops);
       }
       ReplaceNode(Node, CNode);
       return;
     }
     }
     break;
   }
-  case ISD::BRIND: {
+  case ISD::BRIND:
+  case X86ISD::NT_BRIND: {
     if (Subtarget->isTargetNaCl())
       // NaCl has its own pass where jmp %r32 are converted to jmp %r64. We
       // leave the instruction alone.
       break;
     if (Subtarget->isTarget64BitILP32()) {
       // Converts a 32-bit register to a 64-bit, zero-extended version of
       // it. This is needed because x86-64 can do many things, but jmp %r32
       // ain't one of them.
       SDValue Target = Node->getOperand(1);
       assert(Target.getValueType() == MVT::i32 && "Unexpected VT!");
       SDValue ZextTarget = CurDAG->getZExtOrTrunc(Target, dl, MVT::i64);
-      SDValue Brind = CurDAG->getNode(ISD::BRIND, dl, MVT::Other,
+      SDValue Brind = CurDAG->getNode(Opcode, dl, MVT::Other,
                                       Node->getOperand(0), ZextTarget);
       ReplaceNode(Node, Brind.getNode());
       SelectCode(ZextTarget.getNode());
       SelectCode(Brind.getNode());
       return;
     }
     break;
   }

llvm/test/CodeGen/X86/indirect-branch-tracking.ll

 ; RUN: llc -mtriple=x86_64-unknown-unknown < %s | FileCheck %s --check-prefix=ALL --check-prefix=X86_64
+; RUN: llc -mtriple=x86_64-unknown-unknown-gnux32 < %s | FileCheck %s --check-prefix=ALL --check-prefix=X86_64
 ; RUN: llc -mtriple=i386-unknown-unknown < %s | FileCheck %s --check-prefix=ALL --check-prefix=X86
 ; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39439.
 ; RUN: llc -mtriple i386-windows-gnu -exception-model sjlj -verify-machineinstrs=0 < %s | FileCheck %s --check-prefix=SJLJ
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Test1
 ;; -----
 ;; Checks ENDBR insertion in case of switch case statement.