Summary:
Fix the behavior of StringRef::count(StringRef) to not count overlapping occurrences, as is stated in the documentation.
Fixes bug https://bugs.llvm.org/show_bug.cgi?id=44072
I added Krzysztof Parzyszek to review this change because a use of this function in HexagonInstrInfo::getInlineAsmLength might depend on the overlapping-behavior. I don't have enough domain knowledge to tell if this change could break anything there.
All other uses of this method in LLVM (besides the unit tests) only use single-character search strings. In those cases, search occurrences can not overlap anyway.
Patch by Benno (@Bensge)
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D70585
size_t N = Str.size();
if (N > Length)
return 0;
- for (size_t i = 0, e = Length - N + 1; i != e; ++i)
- if (substr(i, N).equals(Str))
+ for (size_t i = 0, e = Length - N + 1; i < e;) {
+ if (substr(i, N).equals(Str)) {
++Count;
+ i += N;
+ }
+ else
+ ++i;
+ }
return Count;
}
EXPECT_EQ(1U, Str.count("hello"));
EXPECT_EQ(1U, Str.count("ello"));
EXPECT_EQ(0U, Str.count("zz"));
+
+ StringRef OverlappingAbba("abbabba");
+ EXPECT_EQ(1U, OverlappingAbba.count("abba"));
+ StringRef NonOverlappingAbba("abbaabba");
+ EXPECT_EQ(2U, NonOverlappingAbba.count("abba"));
+ StringRef ComplexAbba("abbabbaxyzabbaxyz");
+ EXPECT_EQ(2U, ComplexAbba.count("abba"));
}
TEST(StringRefTest, EditDistance) {