[C API] Add function to create ConstantRange attributes to C API

llvm/docs/ReleaseNotes.rst

@@ -161,6 +161,8 @@ Changes to the C API
 * Added ``LLVMAtomicRMWBinOpUIncWrap`` and ``LLVMAtomicRMWBinOpUDecWrap`` to
   ``LLVMAtomicRMWBinOp`` enum for AtomicRMW instructions.
 
+* Added ``LLVMCreateConstantRangeAttribute`` function for creating ConstantRange Attributes.
+
 Changes to the CodeGen infrastructure
 -------------------------------------
 

llvm/include/llvm-c/Core.h

@@ -673,6 +673,18 @@ LLVMAttributeRef LLVMCreateTypeAttribute(LLVMContextRef C, unsigned KindID,
  */
 LLVMTypeRef LLVMGetTypeAttributeValue(LLVMAttributeRef A);
 
+/**
+ * Create a ConstantRange attribute.
+ *
+ * LowerWords and UpperWords need to be NumBits divided by 64 rounded up
+ * elements long.
+ */
+LLVMAttributeRef LLVMCreateConstantRangeAttribute(LLVMContextRef C,
+                                                  unsigned KindID,
+                                                  unsigned NumBits,
+                                                  const uint64_t LowerWords[],
+                                                  const uint64_t UpperWords[]);
+
 /**
  * Create a string attribute.
  */

llvm/lib/IR/Core.cpp

@@ -14,6 +14,7 @@
 #include "llvm-c/Core.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DerivedTypes.h"
@@ -33,6 +34,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
@@ -178,6 +180,20 @@ LLVMTypeRef LLVMGetTypeAttributeValue(LLVMAttributeRef A) {
   return wrap(Attr.getValueAsType());
 }
 
+LLVMAttributeRef LLVMCreateConstantRangeAttribute(LLVMContextRef C,
+                                                  unsigned KindID,
+                                                  unsigned NumBits,
+                                                  const uint64_t LowerWords[],
+                                                  const uint64_t UpperWords[]) {
+  auto &Ctx = *unwrap(C);
+  auto AttrKind = (Attribute::AttrKind)KindID;
+  unsigned NumWords = divideCeil(NumBits, 64);
+  return wrap(Attribute::get(
+      Ctx, AttrKind,
+      ConstantRange(APInt(NumBits, ArrayRef(LowerWords, NumWords)),
+                    APInt(NumBits, ArrayRef(UpperWords, NumWords)))));
+}
+
 LLVMAttributeRef LLVMCreateStringAttribute(LLVMContextRef C,
                                            const char *K, unsigned KLength,
                                            const char *V, unsigned VLength) {

llvm/unittests/IR/AttributesTest.cpp

@@ -7,8 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/Attributes.h"
+#include "llvm-c/Core.h"
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/IR/AttributeMask.h"
+#include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/LLVMContext.h"
@@ -308,4 +310,34 @@ TEST(Attributes, RemoveParamAttributes) {
   EXPECT_EQ(AL.getNumAttrSets(), 0U);
 }
 
+TEST(Attributes, ConstantRangeAttributeCAPI) {
+  LLVMContext C;
+  {
+    const unsigned NumBits = 8;
+    const uint64_t LowerWords[] = {0};
+    const uint64_t UpperWords[] = {42};
+
+    ConstantRange Range(APInt(NumBits, ArrayRef(LowerWords)),
+                        APInt(NumBits, ArrayRef(UpperWords)));
+
+    Attribute RangeAttr = Attribute::get(C, Attribute::Range, Range);
+    auto OutAttr = unwrap(LLVMCreateConstantRangeAttribute(
+        wrap(&C), Attribute::Range, NumBits, LowerWords, UpperWords));
+    EXPECT_EQ(OutAttr, RangeAttr);
+  }
+  {
+    const unsigned NumBits = 128;
+    const uint64_t LowerWords[] = {1, 1};
+    const uint64_t UpperWords[] = {42, 42};
+
+    ConstantRange Range(APInt(NumBits, ArrayRef(LowerWords)),
+                        APInt(NumBits, ArrayRef(UpperWords)));
+
+    Attribute RangeAttr = Attribute::get(C, Attribute::Range, Range);
+    auto OutAttr = unwrap(LLVMCreateConstantRangeAttribute(
+        wrap(&C), Attribute::Range, NumBits, LowerWords, UpperWords));
+    EXPECT_EQ(OutAttr, RangeAttr);
+  }
+}
+
 } // end anonymous namespace