[Mlir-commits] [mlir] IntegerAttr accessor returning APInt by reference. (PR #187351)

[llvmlistbot at llvm.org]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir-core

Author: Jacques Pienaar (jpienaar)

<details>
<summary>Changes</summary>

IntegerAttr accessor getValue() returns an APInt by value. This works well for the case where APInt is small, but leads to unnecessary copies for larger bitwidths. This change provides a getValueRef() accessor that returns a const APInt& directly.

I considered having the regular accessor return a const reference. This would similar to what we do for StringAttr. This would change the lifetime expectations of the existing attribute though.

---
Full diff: https://github.com/llvm/llvm-project/pull/187351.diff


4 Files Affected:

- (modified) mlir/include/mlir/IR/BuiltinAttributes.td (+3) 
- (modified) mlir/lib/CAPI/IR/BuiltinAttributes.cpp (+1-1) 
- (modified) mlir/lib/Dialect/Arith/IR/ArithOps.cpp (+2-2) 
- (modified) mlir/lib/IR/BuiltinAttributes.cpp (+3-1) 


``````````diff
diff --git a/mlir/include/mlir/IR/BuiltinAttributes.td b/mlir/include/mlir/IR/BuiltinAttributes.td
index dced379d1f979..8a242b5127cc4 100644
--- a/mlir/include/mlir/IR/BuiltinAttributes.td
+++ b/mlir/include/mlir/IR/BuiltinAttributes.td
@@ -764,6 +764,9 @@ def Builtin_IntegerAttr : Builtin_Attr<"Integer", "integer",
     /// the attribute.  This traps on signless integers types!
     APSInt getAPSInt() const;
 
+    /// Return the integer value as a reference to an APInt.
+    const APInt &getValueRef() const;
+
   private:
     /// Return a boolean attribute. This is a special variant of the `get`
     /// method that is used by the MLIRContext to cache the boolean IntegerAttr
diff --git a/mlir/lib/CAPI/IR/BuiltinAttributes.cpp b/mlir/lib/CAPI/IR/BuiltinAttributes.cpp
index 65d72801889ec..08d57d6d3ee36 100644
--- a/mlir/lib/CAPI/IR/BuiltinAttributes.cpp
+++ b/mlir/lib/CAPI/IR/BuiltinAttributes.cpp
@@ -184,7 +184,7 @@ unsigned mlirIntegerAttrGetValueNumWords(MlirAttribute attr) {
 }
 
 void mlirIntegerAttrGetValueWords(MlirAttribute attr, uint64_t *words) {
-  const APInt &value = llvm::cast<IntegerAttr>(unwrap(attr)).getValue();
+  const APInt &value = llvm::cast<IntegerAttr>(unwrap(attr)).getValueRef();
   unsigned numWords = value.getNumWords();
   const uint64_t *rawData = value.getRawData();
   std::copy(rawData, rawData + numWords, words);
diff --git a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
index f26aef625fd4a..b7bf29360c886 100644
--- a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
+++ b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
@@ -42,8 +42,8 @@ static IntegerAttr
 applyToIntegerAttrs(PatternRewriter &builder, Value res, Attribute lhs,
                     Attribute rhs,
                     function_ref<APInt(const APInt &, const APInt &)> binFn) {
-  APInt lhsVal = llvm::cast<IntegerAttr>(lhs).getValue();
-  APInt rhsVal = llvm::cast<IntegerAttr>(rhs).getValue();
+  const APInt &lhsVal = llvm::cast<IntegerAttr>(lhs).getValueRef();
+  const APInt &rhsVal = llvm::cast<IntegerAttr>(rhs).getValueRef();
   APInt value = binFn(lhsVal, rhsVal);
   return IntegerAttr::get(res.getType(), value);
 }
diff --git a/mlir/lib/IR/BuiltinAttributes.cpp b/mlir/lib/IR/BuiltinAttributes.cpp
index bbbc9198a68ab..5b0a65832e799 100644
--- a/mlir/lib/IR/BuiltinAttributes.cpp
+++ b/mlir/lib/IR/BuiltinAttributes.cpp
@@ -362,6 +362,8 @@ StringAttr SymbolRefAttr::getLeafReference() const {
 // IntegerAttr
 //===----------------------------------------------------------------------===//
 
+const APInt &IntegerAttr::getValueRef() const { return getImpl()->value; }
+
 int64_t IntegerAttr::getInt() const {
   assert((getType().isIndex() || getType().isSignlessInteger()) &&
          "must be signless integer");
@@ -383,7 +385,7 @@ uint64_t IntegerAttr::getUInt() const {
 APSInt IntegerAttr::getAPSInt() const {
   assert(!getType().isSignlessInteger() &&
          "Signless integers don't carry a sign for APSInt");
-  return APSInt(getValue(), getType().isUnsignedInteger());
+  return APSInt(getValueRef(), getType().isUnsignedInteger());
 }
 
 LogicalResult IntegerAttr::verify(function_ref<InFlightDiagnostic()> emitError,

``````````

</details>


https://github.com/llvm/llvm-project/pull/187351