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Fix bug: PR93

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9752 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-11-06 19:18:49 +00:00
parent 6d7aad1dd5
commit d7222ec801
1 changed files with 29 additions and 0 deletions
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29
lib/Transforms/IPO/LowerSetJmp.cpp
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@ -41,6 +41,7 @@
#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Transforms/Utils/DemoteRegToStack.h"
#include "Support/DepthFirstIterator.h"
#include "Support/Statistic.h"
#include "Support/StringExtras.h"
@ -377,6 +378,34 @@ void LowerSetJmp::TransformSetJmpCall(CallInst* Inst)
SetJmpIDMap[Func]++), 0),
"", Inst);
// We are guaranteed that there are no values live across basic blocks
// (because we are "not in SSA form" yet), but there can still be values live
// in basic blocks. Because of this, splitting the setjmp block can cause
// values above the setjmp to not dominate uses which are after the setjmp
// call. For all of these occasions, we must spill the value to the stack.
//
std::set<Instruction*> InstrsAfterCall;
// The call is probably very close to the end of the basic block, for the
// common usage pattern of: 'if (setjmp(...))', so keep track of the
// instructions after the call.
for (BasicBlock::iterator I = ++BasicBlock::iterator(Inst), E = ABlock->end();
I != E; ++I)
InstrsAfterCall.insert(I);
for (BasicBlock::iterator II = ABlock->begin();
II != BasicBlock::iterator(Inst); ++II)
// Loop over all of the uses of instruction. If any of them are after the
// call, "spill" the value to the stack.
for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
UI != E; ++UI)
if (cast<Instruction>(*UI)->getParent() != ABlock ||
InstrsAfterCall.count(cast<Instruction>(*UI))) {
DemoteRegToStack(*II);
break;
}
InstrsAfterCall.clear();
// Change the setjmp call into a branch statement. We'll remove the
// setjmp call in a little bit. No worries.
BasicBlock* SetJmpContBlock = ABlock->splitBasicBlock(Inst);