[mlir]Why does the following error occur when using -pass-pipeline="builtin.module(func.func(tosa-to-linalg))" to lower tosa.mul?

[loratadineH]

environments:

Ubuntu 22.04 / LLVM-19.1.0-Linux-X64
commit id：a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4

bash command:

mlir-opt -pass-pipeline="builtin.module(func.func(tosa-to-linalg))"  ../input/input.mlir  -o ../output/res.mlir

test case:

func.func @test_mul(%arg0: tensor<13x21x3xf32>, %arg1: tensor<13x1x3xf32>) -> tensor<13x21x3xf32> {
  %0 = tosa.mul %arg0, %arg1 {shift = 1 : i8} : (tensor<13x21x3xf32>, tensor<13x1x3xf32>) -> tensor<13x21x3xf32>
  return %0 : tensor<13x21x3xf32>
}

error:

/home/workdir/input/input.mlir:2:8: error: failed to legalize operation 'tosa.mul'
  %0 = tosa.mul %arg0, %arg1 {shift = 1 : i8} : (tensor<13x21x3xf32>, tensor<13x1x3xf32>) -> tensor<13x21x3xf32>
       ^
/home/workdir/input/manual_input.mlir:2:8: note: see current operation: %0 = "tosa.mul"(%arg0, %arg1) <{shift = 1 : i8}> : (tensor<13x21x3xf32>, tensor<13x1x3xf32>) -> tensor<13x21x3xf32>

But this pass works fine for following input file(change {shift = 1 : i8} to {shift = 0 : i8}):

func.func @test_mul(%arg0: tensor<13x21x3xf32>, %arg1: tensor<13x1x3xf32>) -> tensor<13x21x3xf32> {
  %0 = tosa.mul %arg0, %arg1 {shift = 0 : i8} : (tensor<13x21x3xf32>, tensor<13x1x3xf32>) -> tensor<13x21x3xf32>
  return %0 : tensor<13x21x3xf32>
}

[CoTinker]

tosa.mul can't have shift value for float.

llvm-project/mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp

Lines 81 to 89 in c3bbc3a

	// tosa::MulOp
	if (isa<tosa::MulOp>(op) && isa<FloatType>(elementTy)) {
	if (dyn_cast<tosa::MulOp>(op).getShift() != 0) {
	(void)rewriter.notifyMatchFailure(op,
	"Cannot have shift value for float");
	return nullptr;
	}
	return rewriter.create<arith::MulFOp>(loc, resultTypes, args);
	}

[CoTinker]

Should we add a verifier for tosa.mul that shift value must be zero for float type?
@eric-k256 @GeorgeARM

[eric-k256]

Yes, that seems fine. The spec requires shift to be 0 for float types, it only makes sense for integer types.

[CoTinker]

OKay, I'll open a PR to do that.