[Passes] Switch to xxh3_64bits

FNV is slow and the name StableHashing.h might be misleading. Just use
xxh3_64bits, which has been adopted in many places.

llvm/lib/Passes/StandardInstrumentations.cpp

@@ -14,7 +14,6 @@
 
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/ADT/Any.h"
-#include "llvm/ADT/StableHashing.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/CallGraphSCCPass.h"
 #include "llvm/Analysis/LazyCallGraph.h"
@@ -44,6 +43,7 @@
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/xxhash.h"
 #include <unordered_map>
 #include <unordered_set>
 #include <utility>
@@ -753,28 +753,27 @@ static SmallString<32> getIRFileDisplayName(Any IR) {
   SmallString<32> Result;
   raw_svector_ostream ResultStream(Result);
   const Module *M = unwrapModule(IR);
-  stable_hash NameHash = stable_hash_combine_string(M->getName());
-  unsigned int MaxHashWidth = sizeof(stable_hash) * 8 / 4;
+  uint64_t NameHash = xxh3_64bits(M->getName());
+  unsigned MaxHashWidth = sizeof(uint64_t) * 2;
   write_hex(ResultStream, NameHash, HexPrintStyle::Lower, MaxHashWidth);
   if (unwrapIR<Module>(IR)) {
     ResultStream << "-module";
   } else if (const auto *F = unwrapIR<Function>(IR)) {
     ResultStream << "-function-";
-    stable_hash FunctionNameHash = stable_hash_combine_string(F->getName());
+    auto FunctionNameHash = xxh3_64bits(F->getName());
     write_hex(ResultStream, FunctionNameHash, HexPrintStyle::Lower,
               MaxHashWidth);
   } else if (const auto *C = unwrapIR<LazyCallGraph::SCC>(IR)) {
     ResultStream << "-scc-";
-    stable_hash SCCNameHash = stable_hash_combine_string(C->getName());
+    auto SCCNameHash = xxh3_64bits(C->getName());
     write_hex(ResultStream, SCCNameHash, HexPrintStyle::Lower, MaxHashWidth);
   } else if (const auto *L = unwrapIR<Loop>(IR)) {
     ResultStream << "-loop-";
-    stable_hash LoopNameHash = stable_hash_combine_string(L->getName());
+    auto LoopNameHash = xxh3_64bits(L->getName());
     write_hex(ResultStream, LoopNameHash, HexPrintStyle::Lower, MaxHashWidth);
   } else if (const auto *MF = unwrapIR<MachineFunction>(IR)) {
     ResultStream << "-machine-function-";
-    stable_hash MachineFunctionNameHash =
-        stable_hash_combine_string(MF->getName());
+    auto MachineFunctionNameHash = xxh3_64bits(MF->getName());
     write_hex(ResultStream, MachineFunctionNameHash, HexPrintStyle::Lower,
               MaxHashWidth);
   } else {