Handle more edge cases in intrinsic name binary search
I tried to make the AMDGPU intrinsic info table use this instead of
another StringMatcher, and some issues arose.
llvm-svn: 258871
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 4e08000..40a8ec6 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -414,53 +414,14 @@
#undef GET_INTRINSIC_NAME_TABLE
};
-static int lookupLLVMIntrinsicByName(ArrayRef<const char *> NameTable,
- StringRef Name) {
- // Do a binary search over the table of intrinsic names.
- const char *const *NameEntry =
- std::lower_bound(NameTable.begin(), NameTable.end(), Name.data(),
- [](const char *LHS, const char *RHS) {
- // Don't compare the first 5 characters, they are
- // always "llvm.".
- return strcmp(LHS + 5, RHS + 5) < 0;
- });
- unsigned Idx = NameEntry - NameTable.begin();
-
- // Check if this is a direct match.
- if (Idx < NameTable.size() && strcmp(Name.data(), NameTable[Idx]) == 0)
- return Idx;
-
- // Otherwise, back up one entry to look for a prefix of Name where the next
- // character in Name is a dot.
- if (Idx == 0)
- return -1;
- --Idx;
- bool CheckPrefixes = true;
- while (CheckPrefixes) {
- StringRef FoundName = NameTable[Idx];
- if (Name.startswith(FoundName) && Name[FoundName.size()] == '.')
- return Idx;
- if (Idx == 0)
- return -1;
- --Idx;
- // We have to keep scanning backwards until the previous entry is not a
- // prefix of the current entry. Consider a key of llvm.foo.f64 and a table
- // of llvm.foo and llvm.foo.bar.
- CheckPrefixes = FoundName.startswith(NameTable[Idx]);
- }
-
- return -1;
-}
-
/// \brief This does the actual lookup of an intrinsic ID which
/// matches the given function name.
static Intrinsic::ID lookupIntrinsicID(const ValueName *ValName) {
StringRef Name = ValName->getKey();
- assert(Name.data()[Name.size()] == '\0' && "non-null terminated ValueName");
ArrayRef<const char *> NameTable(&IntrinsicNameTable[1],
std::end(IntrinsicNameTable));
- int Idx = lookupLLVMIntrinsicByName(NameTable, Name);
+ int Idx = Intrinsic::lookupLLVMIntrinsicByName(NameTable, Name);
Intrinsic::ID ID = static_cast<Intrinsic::ID>(Idx + 1);
if (ID == Intrinsic::not_intrinsic)
return ID;