RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 03:33:20 +01:00
Code Issues Projects Releases Wiki Activity

Implement SimplifyCFG/InvokeEliminate.ll

Browse Source 
llvm-svn: 8126
This commit is contained in:
Chris Lattner 2003-08-24 18:36:16 +00:00
parent 507b92d9f9
commit a0203709f4
1 changed files with 36 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -6,7 +6,10 @@
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Constant.h"
#include "llvm/Intrinsics.h"
#include "llvm/iPHINode.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/Support/CFG.h"
#include <algorithm>
#include <functional>
@ -87,12 +90,44 @@ static bool PropagatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) {
// WARNING: The entry node of a function may not be simplified.
//
bool SimplifyCFG(BasicBlock *BB) {
bool Changed = false;
Function *M = BB->getParent();
assert(BB && BB->getParent() && "Block not embedded in function!");
assert(BB->getTerminator() && "Degenerate basic block encountered!");
assert(&BB->getParent()->front() != BB && "Can't Simplify entry block!");
// Check to see if the first instruction in this block is just an
// 'llvm.unwind'. If so, replace any invoke instructions which use this as an
// exception destination with call instructions.
//
if (CallInst *CI = dyn_cast<CallInst>(&BB->front()))
if (Function *F = CI->getCalledFunction())
if (F->getIntrinsicID() == LLVMIntrinsic::unwind) {
std::vector<BasicBlock*> Preds(pred_begin(BB), pred_end(BB));
while (!Preds.empty()) {
BasicBlock *Pred = Preds.back();
if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
if (II->getExceptionalDest() == BB) {
// Insert a new branch instruction before the invoke, because this
// is now a fall through...
BranchInst *BI = new BranchInst(II->getNormalDest(), II);
Pred->getInstList().remove(II); // Take out of symbol table
// Insert the call now...
std::vector<Value*> Args(II->op_begin()+3, II->op_end());
CallInst *CI = new CallInst(II->getCalledValue(), Args,
II->getName(), BI);
// If the invoke produced a value, the Call now does instead
II->replaceAllUsesWith(CI);
delete II;
Changed = true;
}
Preds.pop_back();
}
}
// Remove basic blocks that have no predecessors... which are unreachable.
if (pred_begin(BB) == pred_end(BB) &&
!BB->hasConstantReferences()) {
@ -123,7 +158,7 @@ bool SimplifyCFG(BasicBlock *BB) {
// Check to see if we can constant propagate this terminator instruction
// away...
bool Changed = ConstantFoldTerminator(BB);
Changed |= ConstantFoldTerminator(BB);
// Check to see if this block has no non-phi instructions and only a single
// successor. If so, replace references to this basic block with references