Commit 765b37ab authored by Amara Emerson's avatar Amara Emerson
Browse files

[AArch64][GlobalISel] Fallback if the +strict-align target feature is given. 

Works around PR44246.
parent 8d508c59

llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp

+8 −0
Original line number Diff line number Diff line
@@ -1423,6 +1423,14 @@ bool AArch64InstructionSelector::select(MachineInstr &I) { 
  MachineFunction &MF = *MBB.getParent();

  MachineRegisterInfo &MRI = MF.getRegInfo();



  const AArch64Subtarget *Subtarget =

      &static_cast<const AArch64Subtarget &>(MF.getSubtarget());

  if (Subtarget->requiresStrictAlign()) {

    // We don't support this feature yet.

    LLVM_DEBUG(dbgs() << "AArch64 GISel does not support strict-align yet\n");

    return false;

  }



  unsigned Opcode = I.getOpcode();

  // G_PHI requires same handling as PHI

  if (!isPreISelGenericOpcode(Opcode) || Opcode == TargetOpcode::G_PHI) {

llvm/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll

+9 −0
Original line number Diff line number Diff line
@@ -209,3 +209,12 @@ define <4 x i16> @zext_v4s8(<4 x i8> %in) { 
  ret <4 x i16> %ext

}



; FALLBACK-WITH-REPORT-ERR: remark: <unknown>:0:0: cannot select: RET_ReallyLR implicit $x0 (in function: strict_align_feature)

; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for strict_align_feature

; FALLBACK-WITH-REPORT-OUT-LABEL: strict_align_feature

define i64 @strict_align_feature(i64* %p) #0 {

  %x = load i64, i64* %p, align 1

  ret i64 %x

}



attributes #0 = { "target-features"="+strict-align" }