Use upstream dataflow tooling to build an arithmetic opt pass. (#18702)

This combines several things into one fixpoint iteration:

* Upstream IntRangeOptimizations for taking care of things like constant
replacement for unit ranges.
* Arith canonicalizations.
* Local adaptation of signed->unsigned conversion (upstream's version
can't compose since it is based on dialect conversion for some reason).
It also has 32bit bugs that have been corrected locally.
* Int64/unsigned index conversion.
* Common factor elision for integer division.
* Making the util.assume ops implement InferIntRangeInterface.

I have some additional advanced patterns to the side which simplify a
lot of torch cases, but they need some more baking/testing, so I'm just
landing the basic pass for now to start.

---------

Signed-off-by: Stella Laurenzo <[email protected]>

build_tools/bazel_to_cmake/bazel_to_cmake_targets.py

@@ -58,6 +58,7 @@ def __init__(self, repo_map: Dict[str, str]):
                 ],
                 # MLIR
                 "@llvm-project//mlir:AllPassesAndDialects": ["MLIRAllDialects"],
+                "@llvm-project//mlir:ArithOpsIncGen": ["MLIRArithDialect"],
                 "@llvm-project//mlir:BufferizationInterfaces": [""],
                 "@llvm-project//mlir:CommonFolders": [""],
                 "@llvm-project//mlir:ConversionPasses": [""],

compiler/src/iree/compiler/Dialect/Util/IR/BUILD.bazel

@@ -32,6 +32,7 @@ iree_td_library(
         "@llvm-project//mlir:CallInterfacesTdFiles",
         "@llvm-project//mlir:ControlFlowInterfacesTdFiles",
         "@llvm-project//mlir:FunctionInterfacesTdFiles",
+        "@llvm-project//mlir:InferIntRangeInterfaceTdFiles",
         "@llvm-project//mlir:InferTypeOpInterfaceTdFiles",
         "@llvm-project//mlir:OpBaseTdFiles",
         "@llvm-project//mlir:SideEffectInterfacesTdFiles",

compiler/src/iree/compiler/Dialect/Util/IR/UtilOps.cpp

@@ -8,6 +8,7 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/SMLoc.h"
 #include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/IR/Attributes.h"
@@ -22,6 +23,8 @@
 #include "mlir/Support/LLVM.h"
 #include "mlir/Support/LogicalResult.h"
 
+#include <numeric>
+
 namespace mlir::iree_compiler {
 
 //===----------------------------------------------------------------------===//
@@ -1102,6 +1105,77 @@ namespace mlir::iree_compiler::IREE::Util {
 // util.assume.int
 //===----------------------------------------------------------------------===//
 
+SmallVector<IntAssumptionAttr>
+AssumeIntOp::getOperandAssumptions(unsigned operandIndex) {
+  assert(operandIndex < getNumOperands() &&
+         "getUnionedUnsignedRange operand out of range");
+  auto assumptions = cast<ArrayAttr>(getAssumptions()[operandIndex]);
+  SmallVector<IntAssumptionAttr> results;
+  for (auto assumption : assumptions) {
+    results.push_back(cast<IntAssumptionAttr>(assumption));
+  }
+  return results;
+}
+
+std::pair<std::optional<uint64_t>, std::optional<uint64_t>>
+AssumeIntOp::getUnionedUnsignedRange(unsigned operandIndex) {
+  auto assumptions = getOperandAssumptions(operandIndex);
+  std::optional<uint64_t> uminUnion;
+  std::optional<uint64_t> umaxUnion;
+
+  for (auto assumption : assumptions) {
+    auto umin = assumption.getUmin();
+    auto umax = assumption.getUmax();
+    if (umin) {
+      uminUnion = std::min(
+          *umin, uminUnion ? *uminUnion : std::numeric_limits<uint64_t>::max());
+    }
+    if (umax) {
+      umaxUnion = std::max(
+          *umax, umaxUnion ? *umaxUnion : std::numeric_limits<uint64_t>::min());
+    }
+  }
+  return std::make_pair(uminUnion, umaxUnion);
+}
+
+// Gets the unioned divisor for an operand. If there are multiple divisor
+// assumptions, the gcd of all of them is returned. If there are no
+// divisor assumptions, std::nullopt is returned.
+std::optional<uint64_t> AssumeIntOp::getUnionedDivisor(unsigned operandIndex) {
+  auto assumptions = getOperandAssumptions(operandIndex);
+  std::optional<uint64_t> divisorUnion;
+  for (auto assumption : assumptions) {
+    auto divisor = assumption.getDivisor();
+    if (divisor) {
+      if (divisorUnion)
+        divisorUnion = std::gcd(*divisor, *divisorUnion);
+      else
+        divisorUnion = *divisor;
+    }
+  }
+  return divisorUnion;
+}
+
+void AssumeIntOp::inferResultRanges(ArrayRef<ConstantIntRanges> argRanges,
+                                    SetIntRangeFn setResultRange) {
+  for (auto [index, result] : llvm::enumerate(getResults())) {
+    Type type = result.getType();
+    unsigned bitWidth;
+    if (isa<IndexType>(type))
+      bitWidth = 64;
+    else if (auto intType = dyn_cast<IntegerType>(type))
+      bitWidth = intType.getWidth();
+    else
+      continue;
+    auto [umin, umax] = getUnionedUnsignedRange(index);
+    if (umin && umax) {
+      APInt uminAp(bitWidth, *umin);
+      APInt umaxAp(bitWidth, *umax);
+      setResultRange(result, ConstantIntRanges::fromUnsigned(uminAp, umaxAp));
+    }
+  }
+}
+
 void AssumeIntOp::build(OpBuilder &builder, OperationState &state,
                         Value singleOperand,
                         IntAssumptionAttr singleAssumption) {

compiler/src/iree/compiler/Dialect/Util/IR/UtilOps.h

@@ -19,6 +19,7 @@
 #include "mlir/Interfaces/CastInterfaces.h"
 #include "mlir/Interfaces/ControlFlowInterfaces.h"
 #include "mlir/Interfaces/FunctionInterfaces.h"
+#include "mlir/Interfaces/InferIntRangeInterface.h"
 #include "mlir/Interfaces/InferTypeOpInterface.h"
 #include "mlir/Interfaces/SideEffectInterfaces.h"
 #include "mlir/Interfaces/ViewLikeInterface.h"

compiler/src/iree/compiler/Dialect/Util/IR/UtilOps.td

@@ -18,6 +18,7 @@ include "mlir/Interfaces/CallInterfaces.td"
 include "mlir/Interfaces/CastInterfaces.td"
 include "mlir/Interfaces/ControlFlowInterfaces.td"
 include "mlir/Interfaces/FunctionInterfaces.td"
+include "mlir/Interfaces/InferIntRangeInterface.td"
 include "mlir/Interfaces/InferTypeOpInterface.td"
 include "mlir/Interfaces/SideEffectInterfaces.td"
 include "mlir/Interfaces/ViewLikeInterface.td"
@@ -458,7 +459,9 @@ def OpGroupCompilerHintOps : OpDocGroup {
 
 let opDocGroup = OpGroupCompilerHintOps in {
 
-def Util_AssumeIntOp : Util_PureOp<"assume.int", []> {
+def Util_AssumeIntOp : Util_PureOp<"assume.int", [
+    DeclareOpInterfaceMethods<InferIntRangeInterface, ["inferResultRanges"]>
+]> {
   let summary = "memorializes assumptions about index/integer values.";
   let description = [{
     This op is used to memorialize the result of some integer analysis or
@@ -490,6 +493,23 @@ def Util_AssumeIntOp : Util_PureOp<"assume.int", []> {
     )>,
   ];
 
+  let extraClassDeclaration = [{
+    // Gets the list of assumptions for an operand.
+    SmallVector<IntAssumptionAttr> getOperandAssumptions(unsigned operandIndex);
+
+    // Gets the unioned unsigned range for an operand. If there are multiple
+    // assumptions for the operand, this will return the bounding range for
+    // them all. If there is no umin/umax, then std::nullopt will be returned
+    // for that position.
+    std::pair<std::optional<uint64_t>, std::optional<uint64_t>>
+      getUnionedUnsignedRange(unsigned operandIndex);
+
+    // Gets the unioned divisor for an operand. If there are multiple divisor
+    // assumptions, the gcd of all of them is returned. If there are no
+    // divisor assumptions, std::nullopt is returned.
+    std::optional<uint64_t> getUnionedDivisor(unsigned operandIndex);
+  }];
+
   let hasCustomAssemblyFormat = 1;
   let hasVerifier = 1;
 }

compiler/src/iree/compiler/Dialect/Util/Transforms/BUILD.bazel

@@ -26,6 +26,7 @@ iree_compiler_cc_library(
         "HoistIntoGlobals.cpp",
         "IPO.cpp",
         "ImportResources.cpp",
+        "OptimizeIntArithmetic.cpp",
         "PassDetail.h",
         "Passes.cpp",
         "Patterns.cpp",

compiler/src/iree/compiler/Dialect/Util/Transforms/CMakeLists.txt

@@ -29,6 +29,7 @@ iree_cc_library(
     "HoistIntoGlobals.cpp"
     "IPO.cpp"
     "ImportResources.cpp"
+    "OptimizeIntArithmetic.cpp"
     "PassDetail.h"
     "Passes.cpp"
     "Patterns.cpp"