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Revert 52223. 

llvm-svn: 52243
This commit is contained in:
Evan Cheng 2008-06-12 20:55:39 +00:00
parent accdca1b03
commit 70fe16353a
2 changed files with 2 additions and 20 deletions
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18
llvm/lib/Transforms/Scalar/TailDuplication.cpp
View File

@ -33,7 +33,6 @@
#include "llvm/Support/Debug.h" #include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h" #include "llvm/ADT/Statistic.h"
#include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/LoopInfo.h"
#include <map> #include <map>
using namespace llvm; using namespace llvm;
@ -51,12 +50,10 @@ namespace {
static char ID; // Pass identification, replacement for typeid static char ID; // Pass identification, replacement for typeid
TailDup() : FunctionPass((intptr_t)&ID) {} TailDup() : FunctionPass((intptr_t)&ID) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
private: private:
inline bool shouldEliminateUnconditionalBranch(TerminatorInst *, unsigned); inline bool shouldEliminateUnconditionalBranch(TerminatorInst *, unsigned);
inline void eliminateUnconditionalBranch(BranchInst *BI); inline void eliminateUnconditionalBranch(BranchInst *BI);
SmallPtrSet<BasicBlock*, 4> CycleDetector; SmallPtrSet<BasicBlock*, 4> CycleDetector;
LoopInfo *LI; // The current loop information
}; };
} }
@ -72,9 +69,6 @@ FunctionPass *llvm::createTailDuplicationPass() { return new TailDup(); }
/// a place it already pointed to earlier; see PR 2323. /// a place it already pointed to earlier; see PR 2323.
bool TailDup::runOnFunction(Function &F) { bool TailDup::runOnFunction(Function &F) {
bool Changed = false; bool Changed = false;
LI = &getAnalysis<LoopInfo>();
CycleDetector.clear(); CycleDetector.clear();
for (Function::iterator I = F.begin(), E = F.end(); I != E; ) { for (Function::iterator I = F.begin(), E = F.end(); I != E; ) {
if (shouldEliminateUnconditionalBranch(I->getTerminator(), if (shouldEliminateUnconditionalBranch(I->getTerminator(),
@ -89,10 +83,6 @@ bool TailDup::runOnFunction(Function &F) {
return Changed; return Changed;
} }
void TailDup::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfo>();
}
/// shouldEliminateUnconditionalBranch - Return true if this branch looks /// shouldEliminateUnconditionalBranch - Return true if this branch looks
/// attractive to eliminate. We eliminate the branch if the destination basic /// attractive to eliminate. We eliminate the branch if the destination basic
/// block has <= 5 instructions in it, not counting PHI nodes. In practice, /// block has <= 5 instructions in it, not counting PHI nodes. In practice,
@ -196,14 +186,6 @@ bool TailDup::shouldEliminateUnconditionalBranch(TerminatorInst *TI,
if (!CycleDetector.insert(Dest)) if (!CycleDetector.insert(Dest))
return false; return false;
// Avoid non-natural loops:
// If a loop header is duplicated, the former natural loop will contain two
// paths into the loop --> the loop it not natural anymore. We want to avoid
// this, because other optimizaions may fail to improve the loop because of
// this.
if (LI->isLoopHeader(Dest))
return false;
return true; return true;
} }

4
llvm/test/Transforms/TailDup/2008-06-11-AvoidDupLoopHeader.ll
View File

@ -1,5 +1,5 @@
; RUN: llvm-as < %s | opt -tailduplicate -taildup-threshold=3 -stats -disable-output |& \ ; RUN: llvm-as < %s | opt -tailduplicate -taildup-threshold=3 -stats -disable-output | not grep tailduplicate
; RUN: not grep tailduplicate ; XFAIL: *
define i32 @foo(i32 %l) nounwind { define i32 @foo(i32 %l) nounwind {
entry: entry: