More trivial optimizations to a function well outside the critical path

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92896 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Douglas Gregor 2010-01-07 02:24:06 +00:00
parent 4039bd0550
commit 2772ea831c

View File

@ -8,7 +8,6 @@
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
#include <cstring>
using namespace llvm;
@ -52,21 +51,18 @@ unsigned StringRef::edit_distance(llvm::StringRef Other,
size_type m = size();
size_type n = Other.size();
unsigned SmallPrevious[32];
unsigned SmallCurrent[32];
unsigned *previous = SmallPrevious;
unsigned *current = SmallCurrent;
if (n + 1 > 32) {
previous = new unsigned [n+1];
current = new unsigned [n+1];
}
const unsigned SmallBufferSize = 64;
unsigned SmallBuffer[SmallBufferSize];
unsigned *Allocated = 0;
unsigned *previous = SmallBuffer;
if (2*(n + 1) > SmallBufferSize)
Allocated = previous = new unsigned [2*(n+1)];
unsigned *current = previous + (n + 1);
for (unsigned i = 0; i <= n; ++i)
previous[i] = i;
for (size_type y = 1; y <= m; ++y) {
std::memset(current, 0, (n + 1) * sizeof(unsigned));
current[0] = y;
for (size_type x = 1; x <= n; ++x) {
if (AllowReplacements) {
@ -85,10 +81,7 @@ unsigned StringRef::edit_distance(llvm::StringRef Other,
}
unsigned Result = previous[n];
if (n + 1 > 32) {
delete [] previous;
delete [] current;
}
delete [] Allocated;
return Result;
}