Make the tail duplication threshold accessible from the command line instead of hardcoded

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13025 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-04-18 00:52:43 +00:00
parent f57a43da9c
commit 3c85eef81a

View File

@ -28,11 +28,15 @@
#include "llvm/Support/CFG.h"
#include "llvm/Support/ValueHolder.h"
#include "llvm/Transforms/Utils/Local.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
#include "Support/Statistic.h"
using namespace llvm;
namespace {
cl::opt<unsigned>
Threshold("taildup-threshold", cl::desc("Max block size to tail duplicate"),
cl::init(6), cl::Hidden);
Statistic<> NumEliminated("tailduplicate",
"Number of unconditional branches eliminated");
Statistic<> NumPHINodes("tailduplicate", "Number of phi nodes inserted");
@ -106,7 +110,7 @@ bool TailDup::shouldEliminateUnconditionalBranch(TerminatorInst *TI) {
while (isa<PHINode>(*I)) ++I;
for (unsigned Size = 0; I != Dest->end(); ++Size, ++I)
if (Size == 6) return false; // The block is too large...
if (Size == Threshold) return false; // The block is too large...
// Do not tail duplicate a block that has thousands of successors into a block
// with a single successor if the block has many other predecessors. This can