[X86] Fix LEA compression on 64 bit

[tomershafir]

NDD ADD is only supported on 64 bit, but LEA32 has Requires<[Not64BitMode]>. The reason it doesnt fail upstream is that the predicates check is commented out on X86MCInstLower.cpp:

  // FIXME: Enable feature predicate checks once all the test pass.
  // X86_MC::verifyInstructionPredicates(MI->getOpcode(),
  //                                     Subtarget->getFeatureBits());

Introduced by: #158254

[llvmbot]

@llvm/pr-subscribers-backend-x86

Author: Tomer Shafir (tomershafir)

Changes

NDD ADD is only supported on 64 bit, but LEA32`` has Requires<[Not64BitMode]>. The reason it doesnt fail upstream is that the predicates check is commented out on X86MCInstLower.cpp`:

  // FIXME: Enable feature predicate checks once all the test pass.
  // X86_MC::verifyInstructionPredicates(MI->getOpcode(),
  //                                     Subtarget->getFeatureBits());

Introduced by: #158254

---

Full diff: https://github.com/llvm/llvm-project/pull/166334.diff

1 Files Affected:

• (modified) llvm/lib/Target/X86/X86CompressEVEX.cpp (+1-1)

diff --git a/llvm/lib/Target/X86/X86CompressEVEX.cpp b/llvm/lib/Target/X86/X86CompressEVEX.cpp
index c0c7f5adf06ef..ddbd10d8f7eda 100644
--- a/llvm/lib/Target/X86/X86CompressEVEX.cpp
+++ b/llvm/lib/Target/X86/X86CompressEVEX.cpp
@@ -272,7 +272,7 @@ static bool CompressEVEXImpl(MachineInstr &MI, MachineBasicBlock &MBB,
       const MachineOperand &Src2 = MI.getOperand(2);
       bool Is32BitReg = Opc == X86::ADD32ri_ND || Opc == X86::ADD32rr_ND;
       const MCInstrDesc &NewDesc =
-          ST.getInstrInfo()->get(Is32BitReg ? X86::LEA32r : X86::LEA64r);
+          ST.getInstrInfo()->get(Is32BitReg ? X86::LEA64_32r : X86::LEA64r);
       if (Is32BitReg)
         Src1 = getX86SubSuperRegister(Src1, 64);
       MachineInstrBuilder MIB = BuildMI(MBB, MI, MI.getDebugLoc(), NewDesc, Dst)

[RKSimon]

@tomershafir Are you working towards properly enabling verifyInstructionPredicates ?

[tomershafir]

No, I have just seen this failing on tests with the verification enabled

[tomershafir]

@RKSimon Feel free to add a review, it would be helpful to merge it fast

[phoebewang]

LGTM, thanks for the fix!

[fzou1]

LGTM.