[llvm] f34bb06 - [X86] When expanding LCMPXCHG16B_NO_RBX in EmitInstrWithCustomInserter, directly copy address operands instead of going through X86AddressMode.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2020-10-09T11:55:24-07:00
New Revision: f34bb06935aa3bab353d70d515b767fdd2f5625c

URL: https://github.com/llvm/llvm-project/commit/f34bb06935aa3bab353d70d515b767fdd2f5625c
DIFF: https://github.com/llvm/llvm-project/commit/f34bb06935aa3bab353d70d515b767fdd2f5625c.diff

LOG: [X86] When expanding LCMPXCHG16B_NO_RBX in EmitInstrWithCustomInserter, directly copy address operands instead of going through X86AddressMode.

I suspect getAddressFromInstr and addFullAddress are not handling
all addresses cases properly based on a report from MaskRay.

So just copy the operands directly. This should be more efficient
anyway.

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 9e17cab10643..5d4dfaab4503 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -33765,7 +33765,6 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
   case X86::LCMPXCHG16B_NO_RBX: {
     const X86RegisterInfo *TRI = Subtarget.getRegisterInfo();
     Register BasePtr = TRI->getBaseRegister();
-    X86AddressMode AM = getAddressFromInstr(&MI, 0);
     if (TRI->hasBasePointer(*MF) &&
         (BasePtr == X86::RBX || BasePtr == X86::EBX)) {
       if (!BB->isLiveIn(BasePtr))
@@ -33776,15 +33775,20 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
       BuildMI(*BB, MI, DL, TII->get(TargetOpcode::COPY), SaveRBX)
           .addReg(X86::RBX);
       Register Dst = MF->getRegInfo().createVirtualRegister(&X86::GR64RegClass);
-      addFullAddress(
-          BuildMI(*BB, MI, DL, TII->get(X86::LCMPXCHG16B_SAVE_RBX), Dst), AM)
-          .add(MI.getOperand(X86::AddrNumOperands))
-          .addReg(SaveRBX);
+      MachineInstrBuilder MIB =
+          BuildMI(*BB, MI, DL, TII->get(X86::LCMPXCHG16B_SAVE_RBX), Dst);
+      for (unsigned Idx = 0; Idx < X86::AddrNumOperands; ++Idx)
+        MIB.add(MI.getOperand(Idx));
+      MIB.add(MI.getOperand(X86::AddrNumOperands));
+      MIB.addReg(SaveRBX);
     } else {
       // Simple case, just copy the virtual register to RBX.
       BuildMI(*BB, MI, DL, TII->get(TargetOpcode::COPY), X86::RBX)
           .add(MI.getOperand(X86::AddrNumOperands));
-      addFullAddress(BuildMI(*BB, MI, DL, TII->get(X86::LCMPXCHG16B)), AM);
+      MachineInstrBuilder MIB =
+          BuildMI(*BB, MI, DL, TII->get(X86::LCMPXCHG16B));
+      for (unsigned Idx = 0; Idx < X86::AddrNumOperands; ++Idx)
+        MIB.add(MI.getOperand(Idx));
     }
     MI.eraseFromParent();
     return BB;