[Helion]: Remove boundaryChecks on load operation using a block ptr/te…

bin/RegisterTritonDialects.h

@@ -95,6 +95,7 @@ inline void registerTritonDialects(mlir::DialectRegistry &registry) {
   mlir::test::registerTestTritonAMDGPURangeAnalysis();
   mlir::triton::registerConvertTritonToTritonGPUPass();
   mlir::triton::intel::registerTritonIntelFuseReshape();
+  mlir::triton::intel::registerTritonIntelRemoveBoundaryChecks();
   mlir::triton::intel::registerTritonIntelRemoveMasks();
   mlir::triton::intel::registerTritonIntelTensorDescToBlockPointer();
   mlir::triton::registerRelayoutTritonGPUPass();

third_party/intel/backend/compiler.py

@@ -200,6 +200,7 @@ def make_ttir(mod, metadata, opt):
         passes.ttir.add_rewrite_tensor_descriptor_to_pointer(pm)
         passes.common.add_cse(pm)
         passes.common.add_licm(pm)
+        intel.passes.ttir.add_remove_boundary_checks(pm)
         intel.passes.ttir.add_remove_masks(pm)
         intel.passes.ttir.add_fuse_reshape(pm)
         passes.common.add_canonicalizer(pm)

third_party/intel/include/Dialect/Triton/Transforms/Passes.td

@@ -70,4 +70,41 @@ def TritonIntelFuseReshape
   ];
 }
 
+def TritonIntelRemoveBoundaryChecks
+    : Pass<"triton-intel-remove-boundary-checks", "mlir::ModuleOp"> {
+  let summary = "Remove unnecessary boundary checks from load operations (block pointers only)";
+
+  let description = [{
+    This pass attempts to remove boundary checks that aren't necessary in a tt.load operation.
+    For example, given:
+    %lb = arith.bitcast %c0_i32 : i32 to i32
+    %ub = arith.bitcast %c1024_i32 : i32 to i32
+    %st = arith.bitcast %c64_i32 : i32 to i32
+    scf.for %i = %lb to %ub step %st : i32 {
+      %s0 = arith.constant 512 : i64
+      %s1 = arith.constant 64 : i64
+      %s2 = arith.constant 1024 : i64
+      %a = arith.constant 65536 : i64
+      %b = arith.constant 1 : i64
+      %b = arith.constant 64 : i64
+      %y = arith.constant 0 : i32
+      %ptr = tt.make_tensor_ptr %base, [%s0, %s1, %s2], [%a, %b, %c], [%x, %y, %iv]
+                                {order = array<i32: 2, 1, 0>} : <tensor<1x512x64xf16>>
+      %load = tt.load %ptr {boundaryCheck = array<i32: 2>} : !tt.ptr<tensor<1x512x64xf16>>
+      ...
+      // here %ptr is never updated.
+    }
+
+    The transformation would drop the boundary check on the load operation because:
+      - `%ptr` is never advanced in the loop
+      - `%iv` has values [0, 64, 128, ..., 960], max(%iv) = 960
+      - `%s2` is qual to 1014
+      - the boundary check expression `%iv` < `%s2` is always true
+  }];
+
+  let dependentDialects = [
+    "mlir::triton::TritonDialect"
+  ];
+}
+
 #endif // TRITON_DIALECT_TRITON_INTEL_TRANSFORMS_PASSES

third_party/intel/lib/Dialect/Triton/Transforms/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_triton_library(TritonIntelTransforms
   FuseReshape.cpp
+  RemoveBoundaryChecks.cpp
   RemoveMasks.cpp
   TensorDescToBlockPointer.cpp
 

third_party/intel/lib/Dialect/Triton/Transforms/RemoveBoundaryChecks.cpp

@@ -0,0 +1,189 @@
+
+#include "intel/include/Dialect/Triton/Transforms/Passes.h"
+#include "intel/include/Utils/Utility.h"
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/SCF/IR/SCF.h"
+#include "mlir/Dialect/Utils/StaticValueUtils.h"
+#include "mlir/IR/Verifier.h"
+#include "mlir/Interfaces/InferIntRangeInterface.h"
+#include "mlir/Support/WalkResult.h"
+#include "triton/Dialect/Triton/IR/Dialect.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cmath>
+#include <optional>
+
+#define DEBUG_TYPE "triton-intel-remove-boundary-checks"
+
+using namespace mlir;
+namespace tt = mlir::triton;
+
+namespace mlir::triton::intel {
+#define GEN_PASS_DEF_TRITONINTELREMOVEBOUNDARYCHECKS
+#include "intel/include/Dialect/Triton/Transforms/Passes.h.inc"
+} // namespace mlir::triton::intel
+
+namespace {
+class BoundaryChecksRemover {
+public:
+  void run(ModuleOp moduleOp) {
+    moduleOp.walk([&](tt::LoadOp loadOp) {
+      if (!isCandidate(loadOp))
+        return WalkResult::skip();
+
+      tt::MakeTensorPtrOp makeTensorPtrOp =
+          *tt::intel::findDefiningMakeTensorPtrOp(loadOp.getPtr());
+      LLVM_DEBUG(llvm::dbgs()
+                 << "Analyzing boundaryCheck for: " << loadOp << "\n");
+
+      SmallVector<int> newBoundaryCheck;
+      for (int boundIdx : loadOp.getBoundaryCheck()) {
+        ArrayRef<int> order = makeTensorPtrOp.getOrder();
+        int idx = order.size() - order[boundIdx] - 1;
+        Value offset = makeTensorPtrOp.getOffsets()[idx];
+        Value shape = makeTensorPtrOp.getShape()[idx];
+        std::optional<int64_t> offsetVal = getConstantIntValue(offset),
+                               shapeVal = getConstantIntValue(shape);
+
+        // If the shape is not known at compile time we cannot determine whether
+        // the bound check is unnecessary.
+        if (!shapeVal) {
+          LLVM_DEBUG(llvm::dbgs().indent(2)
+                     << "Check at index " << boundIdx << " is necessary\n");
+          newBoundaryCheck.push_back(boundIdx);
+          continue;
+        }
+
+        // Case 1: offset and shape are constant.
+        if (offsetVal && *offsetVal < *shapeVal) {
+          LLVM_DEBUG(llvm::dbgs().indent(2)
+                     << "Check at index " << boundIdx << " is unnecessary\n");
+          continue;
+        }
+
+        // Case 2: analyze boundary check in loops.
+        if (auto forOp = makeTensorPtrOp->getParentOfType<scf::ForOp>()) {
+          assert(forOp.getSingleInductionVar() && "Single IV expected");
+          Value iv = *forOp.getSingleInductionVar();
+          if (offset != iv) {
+            LLVM_DEBUG(llvm::dbgs().indent(2)
+                       << "Check at index " << boundIdx << " is necessary\n");
+            newBoundaryCheck.push_back(boundIdx);
+            continue;
+          }
+
+          OpFoldResult lb = *forOp.getSingleLowerBound();
+          OpFoldResult ub = *forOp.getSingleUpperBound();
+          OpFoldResult step = *forOp.getSingleStep();
+
+          auto computeLoopIVRange =
+              [&](OpFoldResult lb, OpFoldResult ub,
+                  OpFoldResult step) -> std::optional<ConstantIntRanges> {
+            auto getBoundValue =
+                [](OpFoldResult bound) -> std::optional<int64_t> {
+              if (std::optional<int64_t> opVal = getConstantIntValue(bound))
+                return *opVal;
+
+              Value val = tt::intel::getFinalValue(cast<Value>(bound));
+              if (auto cst = dyn_cast<arith::BitcastOp>(val.getDefiningOp()))
+                val = cst.getIn();
+
+              return getConstantIntValue(getAsOpFoldResult(val));
+            };
+
+            auto areLoopBoundKnown = [&](OpFoldResult lb, OpFoldResult ub,
+                                         OpFoldResult step) {
+              return (getBoundValue(lb) && getBoundValue(ub) &&
+                      getBoundValue(step));
+            };
+
+            if (!areLoopBoundKnown(lb, ub, step))
+              return std::nullopt;
+
+            int64_t lbVal = *getBoundValue(lb);
+            int64_t ubVal = *getBoundValue(ub);
+            int64_t stepVal = *getBoundValue(step);
+            int64_t lastIVVal =
+                lbVal + ((ubVal - lbVal - 1) / stepVal) * stepVal;
+            llvm::APInt start(64, lbVal, true);
+            llvm::APInt end(64, lastIVVal, true);
+
+            return ConstantIntRanges::range(start, end, true);
+          };
+
+          std::optional<ConstantIntRanges> optRange =
+              computeLoopIVRange(lb, ub, step);
+          if (!optRange) {
+            LLVM_DEBUG(llvm::dbgs().indent(2)
+                       << "Check at index " << boundIdx << " is necessary\n");
+            newBoundaryCheck.push_back(boundIdx);
+            continue;
+          }
+
+          // Compare the max value of the loop IV to the offset.
+          APInt max = (*optRange).smax();
+          if (max.getSExtValue() < shapeVal) {
+            LLVM_DEBUG(llvm::dbgs().indent(2)
+                       << "Check at index " << boundIdx << " is unnecessary\n");
+            continue;
+          }
+        }
+
+        LLVM_DEBUG(llvm::dbgs().indent(2)
+                   << "Check at index " << boundIdx << " is necessary\n");
+        newBoundaryCheck.push_back(boundIdx);
+      }
+
+      if (newBoundaryCheck.size() != loadOp.getBoundaryCheck().size()) {
+        loadOp.setBoundaryCheck(newBoundaryCheck);
+        LLVM_DEBUG(llvm::dbgs().indent(2)
+                   << "Rewritten load is: " << loadOp << "\n");
+      }
+
+      return WalkResult::advance();
+    });
+  }
+
+private:
+  // A candidate load operation is one that:
+  //  - has the boundary check attribute
+  //  - uses a block pointer defined by a `make_tensor_ptr` that is not
+  //  advanced
+  bool isCandidate(tt::LoadOp loadOp) const {
+    assert(loadOp && "Expecting a valid load operation");
+
+    ArrayRef<int> boundaryCheck = loadOp.getBoundaryCheck();
+    if (boundaryCheck.empty())
+      return false;
+
+    Type ptrType = loadOp.getPtr().getType();
+    if (!tt::isTensorPointerType(ptrType))
+      return false;
+
+    std::optional<tt::MakeTensorPtrOp> makeTensorPtrOp =
+        tt::intel::findDefiningMakeTensorPtrOp(loadOp.getPtr());
+    if (!makeTensorPtrOp)
+      return false;
+
+    if (llvm::any_of((*makeTensorPtrOp)->getUsers(),
+                     [](Operation *user) { return isa<tt::AdvanceOp>(user); }))
+      return false;
+
+    return true;
+  }
+};
+
+} // namespace
+
+struct TritonIntelRemoveBoundaryChecks
+    : tt::intel::impl::TritonIntelRemoveBoundaryChecksBase<
+          TritonIntelRemoveBoundaryChecks> {
+public:
+  void runOnOperation() final {
+    ModuleOp moduleOp = getOperation();
+    BoundaryChecksRemover remover;
+    remover.run(moduleOp);
+    assert(succeeded(verify(moduleOp)) && "Module verification failed");
+  }
+};

third_party/intel/triton_xpu.cc

@@ -58,6 +58,8 @@ static uint32_t findKernels(llvm::Module &M,
 void init_triton_intel_passes_ttir(py::module &&m) {
   ADD_PASS_WRAPPER_0("add_convert_tdesc_to_block_pointer",
                      intel::createTritonIntelTensorDescToBlockPointer);
+  ADD_PASS_WRAPPER_0("add_remove_boundary_checks",
+                     intel::createTritonIntelRemoveBoundaryChecks);
   ADD_PASS_WRAPPER_0("add_remove_masks", intel::createTritonIntelRemoveMasks);
   ADD_PASS_WRAPPER_0("add_fuse_reshape", intel::createTritonIntelFuseReshape);
 }