6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-24 22:24:54 +00:00
Code Issues Projects Releases Wiki Activity

Do early taildup of ret in CodeGenPrepare for potential tail calls that have a

Browse Source 
void return type. This fixes PR9487.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128197 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Cameron Zwarich
2011-03-24 04:52:10 +00:00
parent 4bae588c75
commit 6e8ffc1c4d
2 changed files with 74 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

54
lib/Transforms/Scalar/CodeGenPrepare.cpp
View File

@@ -594,15 +594,12 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) {
return false;
Value *V = RI->getReturnValue();
if (!V)
return false;
PHINode *PN = dyn_cast<PHINode>(V);
if (!PN)
PHINode *PN = V ? dyn_cast<PHINode>(V) : NULL;
if (V && !PN)
return false;
BasicBlock *BB = RI->getParent();
if (PN->getParent() != BB)
if (PN && PN->getParent() != BB)
return false;
// It's not safe to eliminate the sign / zero extension of the return value.
@@ -612,21 +609,44 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) {
if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt))
return false;
// Make sure there are no instructions between PHI and return.
BasicBlock::iterator BI = PN;
do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
if (&*BI != RI)
return false;
// Make sure there are no instructions between the PHI and return, or that the
// return is the first instruction in the block.
if (PN) {
BasicBlock::iterator BI = BB->begin();
do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
if (&*BI != RI)
return false;
} else {
if (&*BB->begin() != RI)
return false;
}
/// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
/// call.
SmallVector<CallInst*, 4> TailCalls;
for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
// Make sure the phi value is indeed produced by the tail call.
if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) &&
TLI->mayBeEmittedAsTailCall(CI))
TailCalls.push_back(CI);
if (PN) {
for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
// Make sure the phi value is indeed produced by the tail call.
if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) &&
TLI->mayBeEmittedAsTailCall(CI))
TailCalls.push_back(CI);
}
} else {
SmallPtrSet<BasicBlock*, 4> VisitedBBs;
for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
if (!VisitedBBs.insert(*PI))
continue;
BasicBlock::InstListType &InstList = (*PI)->getInstList();
BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
if (++RI == RE)
continue;
CallInst *CI = dyn_cast<CallInst>(&*RI);
if (CI && CI->getType()->isVoidTy() && TLI->mayBeEmittedAsTailCall(CI))
TailCalls.push_back(CI);
}
}
bool Changed = false;