[mlir][tosa] Allow shift operand of tosa::MulOp as non-constant (llvm#155197)

The shift operand of tosa::MulOp could be non-constant when the dynamic
extension enabled. Given that checkConstantOperandMul could check the
shift operand according to the extension, we might able to relax the
checking in TosaToLinalg.

Relative discussion:
https://discourse.llvm.org/t/tosa-ext-dynamic-clearification-needed/87478?u=r2333333.

Author: ShivaChen

mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp

@@ -126,12 +126,12 @@ static Value createLinalgBodyCalculationForElementwiseOp(
   if (isa<tosa::MulOp>(op)) {
     auto shiftVal = cast<tosa::MulOp>(op).getShift();
     DenseElementsAttr shiftElem;
-    if (!matchPattern(shiftVal, m_Constant(&shiftElem))) {
-      (void)rewriter.notifyMatchFailure(op, "shift value of mul not found");
-      return nullptr;
-    }
-
-    int32_t shift = shiftElem.getValues<IntegerAttr>()[0].getInt();
+    bool shiftIsConstant = true;
+    int32_t shift = 0;
+    if (matchPattern(shiftVal, m_Constant(&shiftElem)))
+      shift = shiftElem.getValues<IntegerAttr>()[0].getInt();
+    else
+      shiftIsConstant = false;
 
     if (isa<FloatType>(elementTy)) {
       if (shift != 0) {
@@ -147,23 +147,24 @@ static Value createLinalgBodyCalculationForElementwiseOp(
       Value a = args[0];
       Value b = args[1];
 
-      if (shift > 0) {
-        auto shiftConst =
-            arith::ConstantIntOp::create(rewriter, loc, shift, /*bitwidth=*/8);
+      if (shift > 0 || !shiftIsConstant) {
+        Value shiftConst;
+        if (shiftIsConstant)
+          shiftConst =
+              rewriter.create<arith::ConstantIntOp>(loc, shift, /*bitwidth=*/8);
+
         if (!a.getType().isInteger(32))
           a = arith::ExtSIOp::create(rewriter, loc, rewriter.getI32Type(), a);
 
         if (!b.getType().isInteger(32))
           b = arith::ExtSIOp::create(rewriter, loc, rewriter.getI32Type(), b);
 
+        auto shiftAmount = shiftIsConstant ? shiftConst : args[2];
         auto result = tosa::ApplyScaleOp::create(
-            rewriter, loc, rewriter.getI32Type(), a, b, shiftConst,
+            rewriter, loc, rewriter.getI32Type(), a, b, shiftAmount,
             rewriter.getStringAttr("SINGLE_ROUND"));
 
-        if (elementTy.isInteger(32))
-          return result;
-
-        return arith::TruncIOp::create(rewriter, loc, elementTy, result);
+        return result;
       }
 
       int aWidth = a.getType().getIntOrFloatBitWidth();
@@ -918,6 +919,18 @@ broadcastDynamicDimensions(PatternRewriter &rewriter, Location loc,
   if (operands.size() == 1)
     return operands;
 
+  // No need to broadcast for static shape
+  bool hasDynamic = false;
+  for (auto op : operands) {
+    const auto tType = dyn_cast<RankedTensorType>(op.getType());
+    if (tType && !tType.hasStaticShape()) {
+      hasDynamic = true;
+      break;
+    }
+  }
+  if (!hasDynamic)
+    return operands;
+
   // Broadcast dynamic dimensions operand by operand
   return llvm::map_to_vector(operands, [&](Value operand) {
     return broadcastDynamicDimensions(rewriter, loc, indexPool, operand,
@@ -990,8 +1003,14 @@ emitElementwiseComputation(ConversionPatternRewriter &rewriter, Location loc,
 static ValueRange getBroadcastableOperands(Operation *operation,
                                            ValueRange operands) {
   // Shift cannot broadcast
-  if (isa<tosa::MulOp>(operation))
-    return operands.take_front(2);
+  if (isa<tosa::MulOp>(operation)) {
+    DenseElementsAttr shiftElems;
+    // Shift cannot broadcast when it is constant
+    if (matchPattern(operation->getOperand(2), m_Constant(&shiftElems)))
+      return operands.take_front(2);
+    else
+      return operands.take_front(3);
+  }
   // Input1_zp and output_zp cannot broadcast
   if (isa<tosa::NegateOp>(operation))
     return operands.take_front(1);

mlir/test/Conversion/TosaToLinalg/tosa-to-linalg-invalid.mlir

@@ -73,11 +73,3 @@ func.func @unranked_gather(%arg0: tensor<13x21x3xf32>, %arg1: tensor<13x26xi32>)
   %0 = tosa.gather %arg0, %arg1 : (tensor<13x21x3xf32>, tensor<13x26xi32>) -> tensor<*xf32>
   return %0 : tensor<*xf32>
 }
-
-// -----
-
-func.func @mul_no_const_shift(%arg0: tensor<2x3xi32>, %arg1: tensor<2x3xi32>, %arg2: tensor<1xi8>) -> tensor<2x3xi32> {
-  // expected-error@+1 {{failed to legalize operation 'tosa.mul'}}
-  %0 = tosa.mul %arg0, %arg1, %arg2 : (tensor<2x3xi32>, tensor<2x3xi32>, tensor<1xi8>) -> tensor<2x3xi32>
-  return %0 : tensor<2x3xi32>
-}

mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir

@@ -2471,3 +2471,14 @@ func.func @test_0d_input(%arg0: tensor<i32>) -> () {
 
   return
 }
+
+// -----
+
+// CHECK-LABEL: @mul_no_const_shift
+func.func @mul_no_const_shift(%arg0: tensor<2x3xi32>, %arg1: tensor<2x3xi32>, %arg2: tensor<1xi8>) -> tensor<2x3xi32> {
+  // CHECK: linalg.generic
+  // CHECK: ^bb0(%[[ARG0:.*]]: i32, %[[ARG1:.*]]: i32, %[[ARG2:.*]]: i8, %[[OUT:.*]]: i32):
+  // CHECK: tosa.apply_scale %[[ARG0]], %[[ARG1]], %[[ARG2]]
+  %0 = tosa.mul %arg0, %arg1, %arg2 : (tensor<2x3xi32>, tensor<2x3xi32>, tensor<1xi8>) -> tensor<2x3xi32>
+  return %0 : tensor<2x3xi32>
+}