Cleaner + Another Test

Author: goldsteinn

llvm/lib/IR/Attributes.cpp

@@ -1802,19 +1802,11 @@ AttributeList::intersectWith(LLVMContext &C, AttributeList Other) const {
     return *this;
 
   SmallVector<std::pair<unsigned, AttributeSet>> IntersectedAttrs;
-  SmallSet<unsigned, 8> AllIndexes{};
-  AllIndexes.insert(indexes().begin(), indexes().end());
-  AllIndexes.insert(Other.indexes().begin(), Other.indexes().end());
-
-  for (unsigned Idx : AllIndexes) {
-    AttributeSet ThisSet = {};
-    AttributeSet OtherSet = {};
-    if (hasAttributesAtIndex(Idx))
-      ThisSet = getAttributes(Idx);
-    if (Other.hasAttributesAtIndex(Idx))
-      OtherSet = Other.getAttributes(Idx);
-
-    auto IntersectedAS = ThisSet.intersectWith(C, OtherSet);
+  auto IndexIt = index_iterator(std::max(getNumAttrSets(), Other.getNumAttrSets()));
+  for (unsigned Idx : IndexIt) {
+    fprintf(stderr, "Checking Idx: %u\n", Idx);
+    auto IntersectedAS =
+        getAttributes(Idx).intersectWith(C, Other.getAttributes(Idx));
     // If any index fails to intersect, fail.
     if (!IntersectedAS)
       return std::nullopt;

llvm/unittests/IR/AttributesTest.cpp

@@ -596,6 +596,32 @@ TEST(Attributes, SetIntersectByValAlign) {
   }
 }
 
+TEST(Attributes, ListIntersectDifferingMustPreserve) {
+  LLVMContext C;
+  fprintf(stderr, "Starting Test!\n");
+  std::optional<AttributeList> Res;
+  {
+    AttributeList AL0;
+    AttributeList AL1;
+    AL1 = AL1.addFnAttribute(C, Attribute::ReadOnly);
+    AL0 = AL0.addParamAttribute(C, 0, Attribute::SExt);
+    Res = AL0.intersectWith(C, AL1);
+    ASSERT_FALSE(Res.has_value());
+    Res = AL1.intersectWith(C, AL0);
+    ASSERT_FALSE(Res.has_value());
+  }
+  {
+    AttributeList AL0;
+    AttributeList AL1;
+    AL1 = AL1.addFnAttribute(C, Attribute::AlwaysInline);
+    AL0 = AL0.addParamAttribute(C, 0, Attribute::ReadOnly);
+    Res = AL0.intersectWith(C, AL1);
+    ASSERT_FALSE(Res.has_value());
+    Res = AL1.intersectWith(C, AL0);
+    ASSERT_FALSE(Res.has_value());
+  }
+}
+
 TEST(Attributes, ListIntersect) {
   LLVMContext C;
   AttributeList AL0;