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Turn invokes of nounwind functions into ordinary calls.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44280 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2007-11-22 22:24:59 +00:00
parent 920653d41e
commit 73d4bb6676
2 changed files with 63 additions and 1 deletions
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50
lib/Transforms/Scalar/SimplifyCFG.cpp
View File

@ -71,6 +71,28 @@ static void ChangeToUnreachable(Instruction *I) {
}
}
/// ChangeToCall - Convert the specified invoke into a normal call.
static void ChangeToCall(InvokeInst *II) {
BasicBlock *BB = II->getParent();
SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
CallInst *NewCall = new CallInst(II->getCalledValue(), Args.begin(),
Args.end(), "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setParamAttrs(II->getParamAttrs());
II->replaceAllUsesWith(NewCall);
// Follow the call by a branch to the normal destination.
new BranchInst(II->getNormalDest(), II);
// Update PHI nodes in the unwind destination
II->getUnwindDest()->removePredecessor(BB);
BB->getInstList().erase(II);
if (NewCall->use_empty())
BB->getInstList().erase(NewCall);
}
/// IsNoReturn - Return true if the specified call is to a no-return function.
static bool IsNoReturn(const CallInst *CI) {
if (const ParamAttrsList *Attrs = CI->getParamAttrs())
@ -90,6 +112,25 @@ static bool IsNoReturn(const CallInst *CI) {
return false;
}
/// IsNoUnwind - Return true if the specified invoke is to a no-unwind function.
static bool IsNoUnwind(const InvokeInst *II) {
if (const ParamAttrsList *Attrs = II->getParamAttrs())
if (Attrs->paramHasAttr(0, ParamAttr::NoUnwind))
return true;
if (const Function *Callee = II->getCalledFunction()) {
if (const ParamAttrsList *Attrs = Callee->getParamAttrs())
if (Attrs->paramHasAttr(0, ParamAttr::NoUnwind))
return true;
const FunctionType *FT = Callee->getFunctionType();
if (const ParamAttrsList *Attrs = FT->getParamAttrs())
if (Attrs->paramHasAttr(0, ParamAttr::NoUnwind))
return true;
}
return false;
}
static bool MarkAliveBlocks(BasicBlock *BB,
SmallPtrSet<BasicBlock*, 128> &Reachable) {
@ -106,7 +147,7 @@ static bool MarkAliveBlocks(BasicBlock *BB,
// Do a quick scan of the basic block, turning any obviously unreachable
// instructions into LLVM unreachable insts. The instruction combining pass
// canonnicalizes unreachable insts into stores to null or undef.
// canonicalizes unreachable insts into stores to null or undef.
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
if (IsNoReturn(CI)) {
@ -131,6 +172,13 @@ static bool MarkAliveBlocks(BasicBlock *BB,
}
}
// Turn invokes that call 'nounwind' functions into ordinary calls.
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (IsNoUnwind(II)) {
ChangeToCall(II);
Changed = true;
}
Changed |= ConstantFoldTerminator(BB);
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
Worklist.push_back(*SI);

14
test/Transforms/SimplifyCFG/2007-11-22-InvokeNoUnwind.ll Normal file
View File

@ -0,0 +1,14 @@
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep invoke
declare i32 @func(i8*) nounwind
define i32 @test() {
invoke i32 @func( i8* null ) nounwind
to label %Cont unwind label %Other ; <i32>:1 [#uses=0]
Cont: ; preds = %0
ret i32 0
Other: ; preds = %0
ret i32 1
}