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Improve the accuracy of the inlining heuristic looking for the

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case where a static caller is itself inlined everywhere else, and
thus may go away if it doesn't get too big due to inlining other
things into it.  If there are references to the caller other than
calls, it will not be removed; account for this.
This results in same-day completion of the case in PR8853.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122821 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen
2011-01-04 19:01:54 +00:00
parent c2146a6abc
commit c84e3c0c03
1 changed files with 14 additions and 9 deletions
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23
lib/Transforms/IPO/Inliner.cpp
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@@ -252,20 +252,25 @@ bool Inliner::shouldInline(CallSite CS) {
if (Caller->hasLocalLinkage()) { if (Caller->hasLocalLinkage()) {
int TotalSecondaryCost = 0; int TotalSecondaryCost = 0;
bool outerCallsFound = false; bool outerCallsFound = false;
bool allOuterCallsWillBeInlined = true; // This bool tracks what happens if we do NOT inline C into B.
bool someOuterCallWouldNotBeInlined = false; bool callerWillBeRemoved = true;
// This bool tracks what happens if we DO inline C into B.
bool inliningPreventsSomeOuterInline = false;
for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end(); for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
I != E; ++I) { I != E; ++I) {
CallSite CS2(*I); CallSite CS2(*I);
// If this isn't a call to Caller (it could be some other sort // If this isn't a call to Caller (it could be some other sort
// of reference) skip it. // of reference) skip it. Such references will prevent the caller
if (!CS2 || CS2.getCalledFunction() != Caller) // from being removed.
if (!CS2 || CS2.getCalledFunction() != Caller) {
callerWillBeRemoved = false;
continue; continue;
}
InlineCost IC2 = getInlineCost(CS2); InlineCost IC2 = getInlineCost(CS2);
if (IC2.isNever()) if (IC2.isNever())
allOuterCallsWillBeInlined = false; callerWillBeRemoved = false;
if (IC2.isAlways() || IC2.isNever()) if (IC2.isAlways() || IC2.isNever())
continue; continue;
@@ -275,14 +280,14 @@ bool Inliner::shouldInline(CallSite CS) {
float FudgeFactor2 = getInlineFudgeFactor(CS2); float FudgeFactor2 = getInlineFudgeFactor(CS2);
if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2)) if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
allOuterCallsWillBeInlined = false; callerWillBeRemoved = false;
// See if we have this case. We subtract off the penalty // See if we have this case. We subtract off the penalty
// for the call instruction, which we would be deleting. // for the call instruction, which we would be deleting.
if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) && if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
Cost2 + Cost - (InlineConstants::CallPenalty + 1) >= Cost2 + Cost - (InlineConstants::CallPenalty + 1) >=
(int)(CurrentThreshold2 * FudgeFactor2)) { (int)(CurrentThreshold2 * FudgeFactor2)) {
someOuterCallWouldNotBeInlined = true; inliningPreventsSomeOuterInline = true;
TotalSecondaryCost += Cost2; TotalSecondaryCost += Cost2;
} }
} }
@@ -290,10 +295,10 @@ bool Inliner::shouldInline(CallSite CS) {
// one is set very low by getInlineCost, in anticipation that Caller will // one is set very low by getInlineCost, in anticipation that Caller will
// be removed entirely. We did not account for this above unless there // be removed entirely. We did not account for this above unless there
// is only one caller of Caller. // is only one caller of Caller.
if (allOuterCallsWillBeInlined && Caller->use_begin() != Caller->use_end()) if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
TotalSecondaryCost += InlineConstants::LastCallToStaticBonus; TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
if (outerCallsFound && someOuterCallWouldNotBeInlined && if (outerCallsFound && inliningPreventsSomeOuterInline &&
TotalSecondaryCost < Cost) { TotalSecondaryCost < Cost) {
DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() << DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
" Cost = " << Cost << " Cost = " << Cost <<