Dramatically speedup codegen prepare by a) avoiding use of dominator tree and b) doing a separate pass over dbg.value instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137908 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2011-08-18 00:50:51 +00:00
parent 3230e9537d
commit f56ea610ed

View File

@ -58,6 +58,7 @@ STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "
STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads");
STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized");
STATISTIC(NumRetsDup, "Number of return instructions duplicated");
STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved");
static cl::opt<bool> DisableBranchOpts(
"disable-cgp-branch-opts", cl::Hidden, cl::init(false),
@ -110,6 +111,7 @@ namespace {
bool MoveExtToFormExtLoad(Instruction *I);
bool OptimizeExtUses(Instruction *I);
bool DupRetToEnableTailCallOpts(ReturnInst *RI);
bool PlaceDbgValues(Function &F);
};
}
@ -132,6 +134,11 @@ bool CodeGenPrepare::runOnFunction(Function &F) {
// unconditional branch.
EverMadeChange |= EliminateMostlyEmptyBlocks(F);
// llvm.dbg.value is far away from the value then iSel may not be able
// handle it properly. iSel will drop llvm.dbg.value if it can not
// find a node corresponding to the value.
EverMadeChange |= PlaceDbgValues(F);
bool MadeChange = true;
while (MadeChange) {
MadeChange = false;
@ -549,22 +556,6 @@ bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
// From here on out we're working with named functions.
if (CI->getCalledFunction() == 0) return false;
// llvm.dbg.value is far away from the value then iSel may not be able
// handle it properly. iSel will drop llvm.dbg.value if it can not
// find a node corresponding to the value.
if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(CI))
if (Instruction *VI = dyn_cast_or_null<Instruction>(DVI->getValue()))
if (!VI->isTerminator() &&
(DVI->getParent() != VI->getParent() || DT->dominates(DVI, VI))) {
DEBUG(dbgs() << "Moving Debug Value before :\n" << *DVI << ' ' << *VI);
DVI->removeFromParent();
if (isa<PHINode>(VI))
DVI->insertBefore(VI->getParent()->getFirstInsertionPt());
else
DVI->insertAfter(VI);
return true;
}
// We'll need TargetData from here on out.
const TargetData *TD = TLI ? TLI->getTargetData() : 0;
if (!TD) return false;
@ -1156,3 +1147,34 @@ bool CodeGenPrepare::OptimizeBlock(BasicBlock &BB) {
return MadeChange;
}
// llvm.dbg.value is far away from the value then iSel may not be able
// handle it properly. iSel will drop llvm.dbg.value if it can not
// find a node corresponding to the value.
bool CodeGenPrepare::PlaceDbgValues(Function &F) {
bool MadeChange = false;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
Instruction *PrevNonDbgInst = NULL;
for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
Instruction *Insn = BI; ++BI;
DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
if (!DVI) {
PrevNonDbgInst = Insn;
continue;
}
Instruction *VI = dyn_cast_or_null<Instruction>(DVI->getValue());
if (VI && VI != PrevNonDbgInst && !VI->isTerminator()) {
DEBUG(dbgs() << "Moving Debug Value before :\n" << *DVI << ' ' << *VI);
DVI->removeFromParent();
if (isa<PHINode>(VI))
DVI->insertBefore(VI->getParent()->getFirstInsertionPt());
else
DVI->insertAfter(VI);
MadeChange = true;
++NumDbgValueMoved;
}
}
}
return MadeChange;
}