Commit 2e773626 authored by Matt Arsenault's avatar Matt Arsenault Committed by Matt Arsenault
Browse files

GlobalISel: Fix lower bswap for vectors 

This would hit an assertion from trying to use the wrong bitwidth for
the constants.
parent f5943288

llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h

+5 −0
Original line number Diff line number Diff line
@@ -1446,6 +1446,11 @@ public: 
    return buildInstr(TargetOpcode::G_CTTZ_ZERO_UNDEF, {Dst}, {Src0});

  }



  /// Build and insert \p Dst = G_BSWAP \p Src0

  MachineInstrBuilder buildBSwap(const DstOp &Dst, const SrcOp &Src0) {

    return buildInstr(TargetOpcode::G_BSWAP, {Dst}, {Src0});

  }



  /// Build and insert \p Res = G_FADD \p Op0, \p Op1

  MachineInstrBuilder buildFAdd(const DstOp &Dst, const SrcOp &Src0,

                                const SrcOp &Src1,

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

+1 −1
Original line number Diff line number Diff line
@@ -4956,7 +4956,7 @@ LegalizerHelper::lowerBswap(MachineInstr &MI) { 
  Register Dst = MI.getOperand(0).getReg();

  Register Src = MI.getOperand(1).getReg();

  const LLT Ty = MRI.getType(Src);

  unsigned SizeInBytes = Ty.getSizeInBytes();

  unsigned SizeInBytes = (Ty.getScalarSizeInBits() + 7) / 8;

  unsigned BaseShiftAmt = (SizeInBytes - 1) * 8;



  // Swap most and least significant byte, set remaining bytes in Res to zero.

llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp

+43 −0
Original line number Diff line number Diff line
@@ -2473,4 +2473,47 @@ TEST_F(GISelMITest, LowerFFloor) { 
  // Check

  EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;

}



// Test lowering of G_BSWAP

TEST_F(GISelMITest, LowerBSWAP) {

  setUp();

  if (!TM)

    return;



  DefineLegalizerInfo(A, {});



  // Make sure vector lowering doesn't assert.

  auto Cast = B.buildBitcast(LLT::vector(2, 32), Copies[0]);

  auto BSwap = B.buildBSwap(LLT::vector(2, 32), Cast);

  AInfo Info(MF->getSubtarget());

  DummyGISelObserver Observer;

  LegalizerHelper Helper(*MF, Info, Observer, B);

  // Perform Legalization

  EXPECT_EQ(LegalizerHelper::LegalizeResult::Legalized,

            Helper.lower(*BSwap, 0, LLT()));



  auto CheckStr = R"(

  CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY

  CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = G_BITCAST [[COPY]]

  CHECK: [[K24:%[0-9]+]]:_(s32) = G_CONSTANT i32 24

  CHECK: [[SPLAT24:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[K24]]:_(s32), [[K24]]:_(s32)

  CHECK: [[SHL0:%[0-9]+]]:_(<2 x s32>) = G_SHL [[VEC]]:_, [[SPLAT24]]

  CHECK: [[SHR0:%[0-9]+]]:_(<2 x s32>) = G_LSHR [[VEC]]:_, [[SPLAT24]]

  CHECK: [[OR0:%[0-9]+]]:_(<2 x s32>) = G_OR [[SHR0]]:_, [[SHL0]]:_

  CHECK: [[KMASK:%[0-9]+]]:_(s32) = G_CONSTANT i32 65280

  CHECK: [[SPLATMASK:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[KMASK]]:_(s32), [[KMASK]]:_(s32)

  CHECK: [[K8:%[0-9]+]]:_(s32) = G_CONSTANT i32 8

  CHECK: [[SPLAT8:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[K8]]:_(s32), [[K8]]:_(s32)

  CHECK: [[AND0:%[0-9]+]]:_(<2 x s32>) = G_AND [[VEC]]:_, [[SPLATMASK]]:_

  CHECK: [[SHL1:%[0-9]+]]:_(<2 x s32>) = G_SHL [[AND0]]:_, [[SPLAT8]]

  CHECK: [[OR1:%[0-9]+]]:_(<2 x s32>) = G_OR [[OR0]]:_, [[SHL1]]:_

  CHECK: [[SHR1:%[0-9]+]]:_(<2 x s32>) = G_LSHR [[VEC]]:_, [[SPLAT8]]

  CHECK: [[AND1:%[0-9]+]]:_(<2 x s32>) = G_AND [[SHR1]]:_, [[SPLATMASK]]:_

  CHECK: [[BSWAP:%[0-9]+]]:_(<2 x s32>) = G_OR [[OR1]]:_, [[AND1]]:_

  )";



  // Check

  EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;

}



} // namespace