Use a SmallSet when we can to reduce memory allocations.
This speeds up a particular testcase from 0.0302s to 0.0222s in LiveVariables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52819 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index f3a92f2..ab73c97 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -34,6 +34,7 @@
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Config/alloca.h"
#include <algorithm>
@@ -387,7 +388,7 @@
void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
// What parts of the register are previously defined?
- std::set<unsigned> Live;
+ SmallSet<unsigned, 32> Live;
if (PhysRegDef[Reg] || PhysRegUse[Reg]) {
Live.insert(Reg);
for (const unsigned *SS = TRI->getSubRegisters(Reg); *SS; ++SS)