[AMD] remove redundant LDS bypass checks (triton-lang#5002)

This commit removes special cases for MFMA -> Dot Operand
LDS shortcuts. Now it is supported by common linear layout
infrastructure.

No tests are added, mfma-shortcut.mlir already testing this.

include/triton/Analysis/Utility.h

@@ -214,8 +214,6 @@ bool atomicNeedsSharedMemory(Value result);
 
 bool isBlockedToDotShortcut(RankedTensorType srcTy, RankedTensorType dstTy);
 
-bool isMfmaToDotShortcut(RankedTensorType srcTy, RankedTensorType dstTy);
-
 // Return true if the src and dst layout match.
 bool matchMmaV3AndDotOperandLayout(RankedTensorType srcTy,
                                    RankedTensorType dstTy);

lib/Analysis/Allocation.cpp

@@ -113,7 +113,7 @@ ScratchConfig getScratchConfigForCvt(RankedTensorType srcTy,
   Attribute srcLayout = srcTy.getEncoding();
   Attribute dstLayout = dstTy.getEncoding();
 
-  assert(!isMfmaToDotShortcut(srcTy, dstTy));
+  assert(cvtNeedsSharedMemory(srcTy, dstTy));
 
   // FIXME This is NOT entirely correct
   // This should be getElemOrder, but we don't have such a method

lib/Analysis/Utility.cpp

@@ -605,22 +605,6 @@ bool isBlockedToDotShortcut(RankedTensorType srcTy, RankedTensorType dstTy) {
   return matrixDimsCompatible && bDimCompatible;
 }
 
-bool isMfmaToDotShortcut(RankedTensorType srcTy, RankedTensorType dstTy) {
-  auto mfmaLayout = dyn_cast<AMDMfmaEncodingAttr>(srcTy.getEncoding());
-  auto dotOperandLayout = dyn_cast<DotOperandEncodingAttr>(dstTy.getEncoding());
-  if (mfmaLayout == nullptr || dotOperandLayout == nullptr)
-    return false;
-  // TODO: Remove the restriction on the warpsPerCTA once chain dot testing is
-  // improved. In addition, we can enable this shortcut for regular MFMA
-  // layout when opIdx == 1.
-  return mfmaLayout.getWarpsPerCTA()[1] == 1 &&
-         dotOperandLayout.getOpIdx() == 0 && mfmaLayout.getIsTransposed() &&
-         dotOperandLayout.getKWidth() == getContigPerThread(mfmaLayout)[1] &&
-         dotOperandLayout.getParent() == mfmaLayout &&
-         (mfmaLayout.getMDim() == 32 || mfmaLayout.getMDim() == 16) &&
-         (srcTy.getElementType().isF16() || srcTy.getElementType().isBF16());
-}
-
 // For MMAV3 dotOperand layout matches mma operand for f16 and bf16 cases.
 bool matchMmaV3AndDotOperandLayout(RankedTensorType srcTy,
                                    RankedTensorType dstTy) {
@@ -738,8 +722,7 @@ bool cvtNeedsSharedMemory(RankedTensorType srcTy, RankedTensorType dstTy) {
   // supported yet in Triton's backend.
   return !cvtReordersRegisters(srcTy, dstTy) &&
          !isBlockedToDotShortcut(srcTy, dstTy) &&
-         !matchMmaV3AndDotOperandLayout(srcTy, dstTy) &&
-         !isMfmaToDotShortcut(srcTy, dstTy);
+         !matchMmaV3AndDotOperandLayout(srcTy, dstTy);
 }
 
 bool atomicNeedsSharedMemory(Value value) {

third_party/amd/lib/TritonAMDGPUToLLVM/ConvertLayoutOpToLLVM.cpp

@@ -115,64 +115,13 @@ struct LocalLoadOpConversion
   }
 };
 
-struct ConvertLayoutOpConversion
-    : public ConvertOpToLLVMPattern<triton::gpu::ConvertLayoutOp> {
-public:
-  using ConvertOpToLLVMPattern<
-      triton::gpu::ConvertLayoutOp>::ConvertOpToLLVMPattern;
-
-  LogicalResult
-  matchAndRewrite(triton::gpu::ConvertLayoutOp op, OpAdaptor adaptor,
-                  ConversionPatternRewriter &rewriter) const override {
-    Value src = op.getSrc();
-    Value dst = op.getResult();
-    auto srcTy = cast<RankedTensorType>(src.getType());
-    auto dstTy = cast<RankedTensorType>(dst.getType());
-    Attribute srcLayout = srcTy.getEncoding();
-    Attribute dstLayout = dstTy.getEncoding();
-
-    if (isa<AMDMfmaEncodingAttr>(srcLayout) &&
-        isa<DotOperandEncodingAttr>(dstLayout)) {
-      return lowerMfmaToDotOperand(op, adaptor, rewriter);
-    }
-    return failure();
-  }
-
-private:
-  LogicalResult
-  lowerMfmaToDotOperand(triton::gpu::ConvertLayoutOp op, OpAdaptor adaptor,
-                        ConversionPatternRewriter &rewriter) const {
-    auto loc = op.getLoc();
-    RankedTensorType srcTy = op.getSrc().getType();
-    RankedTensorType dstTy = op.getType();
-    if (isMfmaToDotShortcut(srcTy, dstTy)) {
-      // vecSize is an number of sequential elements stored by one thread
-      // - For MFMA encoding (encoding of the result tensor of dot
-      // operation) it is 4
-      // - For MFMA operand encoding it is
-      // dotOperandEncoding::kWidth,
-      //   which is 4 in certain cases (e.g. fp16 and bfloat16 dtypes with kpack
-      //   = 1)
-      //
-      // For cases where these two values are equal MFMA and MFMA operand
-      // layouts are the same.
-      auto vals = unpackLLElements(loc, adaptor.getSrc(), rewriter);
-      Value view =
-          packLLElements(loc, getTypeConverter(), vals, rewriter, dstTy);
-      rewriter.replaceOp(op, view);
-      return success();
-    }
-    return failure();
-  }
-};
 } // namespace
 
 namespace mlir::triton::AMD {
 void populateConvertLayoutOpToLLVMPatterns(
     LLVMTypeConverter &typeConverter, const TargetInfo &targetInfo,
     RewritePatternSet &patterns, int numWarps,
     ModuleAxisInfoAnalysis &axisInfoAnalysis, PatternBenefit benefit) {
-  patterns.add<ConvertLayoutOpConversion>(typeConverter, benefit);
   patterns.add<LocalLoadOpConversion>(typeConverter, benefit);
 }
 } // namespace mlir::triton::AMD

third_party/amd/lib/TritonAMDGPUToLLVM/DecomposeUnsupportedConversions.cpp

@@ -38,8 +38,10 @@ struct DecomposeUnsupportedAMDConversions
 
     triton::gpu::decomposeSplatOpToSharedLayoutConversion(mod);
 
-    triton::gpu::decomposeTensorCoreToDotLayoutConversion(mod,
-                                                          isMfmaToDotShortcut);
+    auto isShortcut =
+        mlir::triton::gpu::ShortcutFn(std::not_fn(cvtNeedsSharedMemory));
+
+    triton::gpu::decomposeTensorCoreToDotLayoutConversion(mod, isShortcut);
 
     /* -------------------------------- */
     // Replace `wmma -> dot_op` with `wmma -> blocked -> dot_op`