[Mlir-commits] [mlir] [mlir][amdgpu] Lower make_gather_dma_descriptor. (PR #172083)

[Erick Ochoa Lopez]

================
@@ -2896,8 +2933,86 @@ struct AMDGPUMakeDmaDescriptorLowering
     return dgroup2;
   }
 
+  Value getGatherIndices(DescriptorOp op, OpAdaptor adaptor,
+                         ConversionPatternRewriter &rewriter, Location loc,
+                         ArrayRef<Value> consts, bool firstHalf) const {
+    IntegerType i32 = rewriter.getI32Type();
+    Type v4i32 = this->typeConverter->convertType(VectorType::get(4, i32));
+    assert(v4i32 && "expected type conversion to succeed.");
+
+    MakeGatherDmaDescriptorOp descriptorOp =
+        cast<MakeGatherDmaDescriptorOp>(op);
+    if (!descriptorOp.getIndices())
+      return LLVM::PoisonOp::create(rewriter, loc, v4i32);
+
+    MakeGatherDmaDescriptorOpAdaptor castedAdaptor =
+        MakeGatherDmaDescriptorOpAdaptor(descriptorOp);
+    Value indices = castedAdaptor.getIndices();
+
+    auto vectorType = cast<VectorType>(indices.getType());
+    unsigned length = vectorType.getShape().back();
+    Type elementType = vectorType.getElementType();
+    unsigned maxLength = elementType == i32 ? 4 : 8;
+    int32_t offset = firstHalf ? 0 : maxLength;
+    unsigned discountedLength =
+        std::max(static_cast<int32_t>(length - offset), 0);
+
+    unsigned targetSize = std::min(maxLength, discountedLength);
+
+    SmallVector<Value> indicesVector;
+    for (unsigned i = offset; i < targetSize + offset; i++) {
+      Value idx;
+      if (i < consts.size())
+        idx = consts[i];
+      else
+        idx = createI32Constant(rewriter, loc, i);
+      Value elem = LLVM::ExtractElementOp::create(rewriter, loc, indices, idx);
+      indicesVector.push_back(elem);
+    }
+
+    SmallVector<Value> indicesI32Vector;
+    if (elementType == i32)
+      indicesI32Vector = indicesVector;
+    else {
----------------
amd-eochoalo wrote:

https://github.com/llvm/llvm-project/pull/172083/commits/37ba4d27cf6f3329434fa0aa9c98e94086b8d1ff

https://github.com/llvm/llvm-project/pull/172083