maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Do not promote globals only used by main to locals if there are constantexprs 

or other uses hanging off of them.

llvm-svn: 22219
This commit is contained in:
Chris Lattner 2005-06-15 21:11:48 +00:00
parent 11b4d966b7
commit 50bdfcb045
1 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
llvm/lib/Transforms/IPO/GlobalOpt.cpp
View File

@ -104,6 +104,10 @@ struct GlobalStatus {
Function *AccessingFunction; Function *AccessingFunction;
bool HasMultipleAccessingFunctions; bool HasMultipleAccessingFunctions;
// HasNonInstructionUser - Set to true if this global has a user that is not
// an instruction (e.g. a constant expr or GV initializer).
bool HasNonInstructionUser;
/// isNotSuitableForSRA - Keep track of whether any SRA preventing users of /// isNotSuitableForSRA - Keep track of whether any SRA preventing users of
/// the global exist. Such users include GEP instruction with variable /// the global exist. Such users include GEP instruction with variable
/// indexes, and non-gep/load/store users like constant expr casts. /// indexes, and non-gep/load/store users like constant expr casts.
@ -111,7 +115,7 @@ struct GlobalStatus {
GlobalStatus() : isLoaded(false), StoredType(NotStored), StoredOnceValue(0), GlobalStatus() : isLoaded(false), StoredType(NotStored), StoredOnceValue(0),
AccessingFunction(0), HasMultipleAccessingFunctions(false), AccessingFunction(0), HasMultipleAccessingFunctions(false),
isNotSuitableForSRA(false) {} HasNonInstructionUser(false), isNotSuitableForSRA(false) {}
}; };
@ -140,6 +144,8 @@ static bool AnalyzeGlobal(Value *V, GlobalStatus &GS,
std::set<PHINode*> &PHIUsers) { std::set<PHINode*> &PHIUsers) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(*UI)) { if (ConstantExpr *CE = dyn_cast<ConstantExpr>(*UI)) {
GS.HasNonInstructionUser = true;
if (AnalyzeGlobal(CE, GS, PHIUsers)) return true; if (AnalyzeGlobal(CE, GS, PHIUsers)) return true;
if (CE->getOpcode() != Instruction::GetElementPtr) if (CE->getOpcode() != Instruction::GetElementPtr)
GS.isNotSuitableForSRA = true; GS.isNotSuitableForSRA = true;
@ -241,11 +247,13 @@ static bool AnalyzeGlobal(Value *V, GlobalStatus &GS,
return true; // Any other non-load instruction might take address! return true; // Any other non-load instruction might take address!
} }
} else if (Constant *C = dyn_cast<Constant>(*UI)) { } else if (Constant *C = dyn_cast<Constant>(*UI)) {
GS.HasNonInstructionUser = true;
// We might have a dead and dangling constant hanging off of here. // We might have a dead and dangling constant hanging off of here.
if (!ConstantIsDead(C)) if (!ConstantIsDead(C))
return true; return true;
} else { } else {
// Otherwise must be a global or some other user. GS.HasNonInstructionUser = true;
// Otherwise must be some other user.
return true; return true;
} }
@ -940,7 +948,7 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
// NOTE: It doesn't make sense to promote non first class types since we // NOTE: It doesn't make sense to promote non first class types since we
// are just replacing static memory to stack memory. // are just replacing static memory to stack memory.
if (!GS.HasMultipleAccessingFunctions && if (!GS.HasMultipleAccessingFunctions &&
GS.AccessingFunction && GS.AccessingFunction && !GS.HasNonInstructionUser &&
GV->getType()->getElementType()->isFirstClassType() && GV->getType()->getElementType()->isFirstClassType() &&
GS.AccessingFunction->getName() == "main" && GS.AccessingFunction->getName() == "main" &&
GS.AccessingFunction->hasExternalLinkage()) { GS.AccessingFunction->hasExternalLinkage()) {