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When considering whether to inline Callee into Caller,

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and that will make Caller too big to inline, see if it
might be better to inline Caller into its callers instead.
This situation is described in PR 2973, although I haven't
tried the specific case in SPASS.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83602 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2009-10-09 00:11:32 +00:00
parent 3645b01002
commit e91b9a3b59
2 changed files with 181 additions and 6 deletions
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76
lib/Transforms/IPO/Inliner.cpp
View File

@ -189,9 +189,9 @@ bool Inliner::shouldInline(CallSite CS) {
int Cost = IC.getValue();
int CurrentThreshold = InlineThreshold;
Function *Fn = CS.getCaller();
if (Fn && !Fn->isDeclaration() &&
Fn->hasFnAttr(Attribute::OptimizeForSize) &&
Function *Caller = CS.getCaller();
if (Caller && !Caller->isDeclaration() &&
Caller->hasFnAttr(Attribute::OptimizeForSize) &&
InlineLimit.getNumOccurrences() == 0 &&
InlineThreshold != 50)
CurrentThreshold = 50;
@ -203,8 +203,72 @@ bool Inliner::shouldInline(CallSite CS) {
return false;
}
// Try to detect the case where the current inlining candidate caller
// (call it B) is a static function and is an inlining candidate elsewhere,
// and the current candidate callee (call it C) is large enough that
// inlining it into B would make B too big to inline later. In these
// circumstances it may be best not to inline C into B, but to inline B
// into its callers.
if (Caller->hasLocalLinkage()) {
int TotalSecondaryCost = 0;
bool outerCallsFound = false;
bool allOuterCallsWillBeInlined = true;
bool someOuterCallWouldNotBeInlined = false;
for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
I != E; ++I) {
CallSite CS2 = CallSite::get(*I);
// If this isn't a call to Caller (it could be some other sort
// of reference) skip it.
if (CS2.getInstruction() == 0 || CS2.getCalledFunction() != Caller)
continue;
InlineCost IC2 = getInlineCost(CS2);
if (IC2.isNever())
allOuterCallsWillBeInlined = false;
if (IC2.isAlways() || IC2.isNever())
continue;
outerCallsFound = true;
int Cost2 = IC2.getValue();
int CurrentThreshold2 = InlineThreshold;
Function *Caller2 = CS2.getCaller();
if (Caller2 && !Caller2->isDeclaration() &&
Caller2->hasFnAttr(Attribute::OptimizeForSize) &&
InlineThreshold != 50)
CurrentThreshold2 = 50;
float FudgeFactor2 = getInlineFudgeFactor(CS2);
if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
allOuterCallsWillBeInlined = false;
// See if we have this case. The magic 6 is what InlineCost assigns
// for the call instruction, which we would be deleting.
if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
Cost2 + Cost - 6 >= (int)(CurrentThreshold2 * FudgeFactor2)) {
someOuterCallWouldNotBeInlined = true;
TotalSecondaryCost += Cost2;
}
}
// If all outer calls to Caller would get inlined, the cost for the last
// one is set very low by getInlineCost, in anticipation that Caller will
// be removed entirely. We did not account for this above unless there
// is only one caller of Caller.
if (allOuterCallsWillBeInlined && Caller->use_begin() != Caller->use_end())
TotalSecondaryCost -= 15000;
if (outerCallsFound && someOuterCallWouldNotBeInlined &&
TotalSecondaryCost < Cost) {
DEBUG(errs() << " NOT Inlining: " << *CS.getInstruction() <<
" Cost = " << Cost <<
", outer Cost = " << TotalSecondaryCost << '\n');
return false;
}
}
DEBUG(errs() << " Inlining: cost=" << Cost
<< ", Call: " << *CS.getInstruction() << "\n");
<< ", Call: " << *CS.getInstruction() << '\n');
return true;
}
@ -232,7 +296,7 @@ bool Inliner::runOnSCC(std::vector<CallGraphNode*> &SCC) {
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
CallSite CS = CallSite::get(I);
// If this this isn't a call, or it is a call to an intrinsic, it can
// If this isn't a call, or it is a call to an intrinsic, it can
// never be inlined.
if (CS.getInstruction() == 0 || isa<IntrinsicInst>(I))
continue;
@ -279,7 +343,7 @@ bool Inliner::runOnSCC(std::vector<CallGraphNode*> &SCC) {
// try to do so.
if (!shouldInline(CS))
continue;
Function *Caller = CS.getCaller();
// Attempt to inline the function...
if (!InlineCallIfPossible(CS, CG, TD, InlinedArrayAllocas))

111
test/Transforms/Inline/nested-inline.ll Normal file
View File

@ -0,0 +1,111 @@
; RUN: opt < %s -inline -S | FileCheck %s
; Test that bar and bar2 are both inlined throughout and removed.
@A = weak global i32 0 ; <i32*> [#uses=1]
@B = weak global i32 0 ; <i32*> [#uses=1]
@C = weak global i32 0 ; <i32*> [#uses=1]
define fastcc void @foo(i32 %X) {
entry:
; CHECK: @foo
%ALL = alloca i32, align 4 ; <i32*> [#uses=1]
%tmp1 = and i32 %X, 1 ; <i32> [#uses=1]
%tmp1.upgrd.1 = icmp eq i32 %tmp1, 0 ; <i1> [#uses=1]
br i1 %tmp1.upgrd.1, label %cond_next, label %cond_true
cond_true: ; preds = %entry
store i32 1, i32* @A
br label %cond_next
cond_next: ; preds = %cond_true, %entry
%tmp4 = and i32 %X, 2 ; <i32> [#uses=1]
%tmp4.upgrd.2 = icmp eq i32 %tmp4, 0 ; <i1> [#uses=1]
br i1 %tmp4.upgrd.2, label %cond_next7, label %cond_true5
cond_true5: ; preds = %cond_next
store i32 1, i32* @B
br label %cond_next7
cond_next7: ; preds = %cond_true5, %cond_next
%tmp10 = and i32 %X, 4 ; <i32> [#uses=1]
%tmp10.upgrd.3 = icmp eq i32 %tmp10, 0 ; <i1> [#uses=1]
br i1 %tmp10.upgrd.3, label %cond_next13, label %cond_true11
cond_true11: ; preds = %cond_next7
store i32 1, i32* @C
br label %cond_next13
cond_next13: ; preds = %cond_true11, %cond_next7
%tmp16 = and i32 %X, 8 ; <i32> [#uses=1]
%tmp16.upgrd.4 = icmp eq i32 %tmp16, 0 ; <i1> [#uses=1]
br i1 %tmp16.upgrd.4, label %UnifiedReturnBlock, label %cond_true17
cond_true17: ; preds = %cond_next13
call void @ext( i32* %ALL )
ret void
UnifiedReturnBlock: ; preds = %cond_next13
ret void
}
; CHECK-NOT: @bar
define internal fastcc void @bar(i32 %X) {
entry:
%ALL = alloca i32, align 4 ; <i32*> [#uses=1]
%tmp1 = and i32 %X, 1 ; <i32> [#uses=1]
%tmp1.upgrd.1 = icmp eq i32 %tmp1, 0 ; <i1> [#uses=1]
br i1 %tmp1.upgrd.1, label %cond_next, label %cond_true
cond_true: ; preds = %entry
store i32 1, i32* @A
br label %cond_next
cond_next: ; preds = %cond_true, %entry
%tmp4 = and i32 %X, 2 ; <i32> [#uses=1]
%tmp4.upgrd.2 = icmp eq i32 %tmp4, 0 ; <i1> [#uses=1]
br i1 %tmp4.upgrd.2, label %cond_next7, label %cond_true5
cond_true5: ; preds = %cond_next
store i32 1, i32* @B
br label %cond_next7
cond_next7: ; preds = %cond_true5, %cond_next
%tmp10 = and i32 %X, 4 ; <i32> [#uses=1]
%tmp10.upgrd.3 = icmp eq i32 %tmp10, 0 ; <i1> [#uses=1]
br i1 %tmp10.upgrd.3, label %cond_next13, label %cond_true11
cond_true11: ; preds = %cond_next7
store i32 1, i32* @C
br label %cond_next13
cond_next13: ; preds = %cond_true11, %cond_next7
%tmp16 = and i32 %X, 8 ; <i32> [#uses=1]
%tmp16.upgrd.4 = icmp eq i32 %tmp16, 0 ; <i1> [#uses=1]
br i1 %tmp16.upgrd.4, label %UnifiedReturnBlock, label %cond_true17
cond_true17: ; preds = %cond_next13
call void @foo( i32 %X )
ret void
UnifiedReturnBlock: ; preds = %cond_next13
ret void
}
define internal fastcc void @bar2(i32 %X) {
entry:
call void @foo( i32 %X )
ret void
}
declare void @ext(i32*)
define void @test(i32 %X) {
entry:
; CHECK: test
; CHECK-NOT: @bar
tail call fastcc void @bar( i32 %X )
tail call fastcc void @bar( i32 %X )
tail call fastcc void @bar2( i32 %X )
tail call fastcc void @bar2( i32 %X )
ret void
; CHECK: ret
}