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Fix indvars randomness by removing iteration over a map. 

I rewrote the algorithm a while back so it doesn't require map lookup,
but neglected to change the data structure. This was caught by
llvm-gcc self host, not because there's anything special about
llvm-gcc, but because it is the only test for nondeterminism we
currently have. Unit tests don't work well for everything; we should
always try to have a nondeterminism stress test running.

Fixes PR11133: llvm-gcc self host .o mismatch after enable-iv-rewrite=false

llvm-svn: 142036
This commit is contained in:
Andrew Trick 2011-10-15 01:38:14 +00:00
parent 09c7464312
commit d50861c831
1 changed files with 12 additions and 12 deletions
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24
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -721,10 +721,11 @@ namespace {
// extend operations. This information is recorded by CollectExtend and
// provides the input to WidenIV.
struct WideIVInfo {
PHINode *NarrowIV;
Type *WidestNativeType; // Widest integer type created [sz]ext
bool IsSigned; // Was an sext user seen before a zext?
WideIVInfo() : WidestNativeType(0), IsSigned(false) {}
WideIVInfo() : NarrowIV(0), WidestNativeType(0), IsSigned(false) {}
};
class WideIVVisitor : public IVVisitor {
@ -734,8 +735,9 @@ namespace {
public:
WideIVInfo WI;
WideIVVisitor(ScalarEvolution *SCEV, const TargetData *TData) :
SE(SCEV), TD(TData) {}
WideIVVisitor(PHINode *NarrowIV, ScalarEvolution *SCEV,
const TargetData *TData) :
SE(SCEV), TD(TData) { WI.NarrowIV = NarrowIV; }
// Implement the interface used by simplifyUsersOfIV.
virtual void visitCast(CastInst *Cast);
@ -812,10 +814,10 @@ class WidenIV {
SmallVector<NarrowIVDefUse, 8> NarrowIVUsers;
public:
WidenIV(PHINode *PN, const WideIVInfo &WI, LoopInfo *LInfo,
WidenIV(const WideIVInfo &WI, LoopInfo *LInfo,
ScalarEvolution *SEv, DominatorTree *DTree,
SmallVectorImpl<WeakVH> &DI) :
OrigPhi(PN),
OrigPhi(WI.NarrowIV),
WideType(WI.WidestNativeType),
IsSigned(WI.IsSigned),
LI(LInfo),
@ -1181,7 +1183,7 @@ PHINode *WidenIV::CreateWideIV(SCEVExpander &Rewriter) {
void IndVarSimplify::SimplifyAndExtend(Loop *L,
SCEVExpander &Rewriter,
LPPassManager &LPM) {
std::map<PHINode *, WideIVInfo> WideIVMap;
SmallVector<WideIVInfo, 8> WideIVs;
SmallVector<PHINode*, 8> LoopPhis;
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) {
@ -1202,24 +1204,22 @@ void IndVarSimplify::SimplifyAndExtend(Loop *L,
PHINode *CurrIV = LoopPhis.pop_back_val();
// Information about sign/zero extensions of CurrIV.
WideIVVisitor WIV(SE, TD);
WideIVVisitor WIV(CurrIV, SE, TD);
Changed |= simplifyUsersOfIV(CurrIV, SE, &LPM, DeadInsts, &WIV);
if (WIV.WI.WidestNativeType) {
WideIVMap[CurrIV] = WIV.WI;
WideIVs.push_back(WIV.WI);
}
} while(!LoopPhis.empty());
for (std::map<PHINode *, WideIVInfo>::const_iterator I = WideIVMap.begin(),
E = WideIVMap.end(); I != E; ++I) {
WidenIV Widener(I->first, I->second, LI, SE, DT, DeadInsts);
for (; !WideIVs.empty(); WideIVs.pop_back()) {
WidenIV Widener(WideIVs.back(), LI, SE, DT, DeadInsts);
if (PHINode *WidePhi = Widener.CreateWideIV(Rewriter)) {
Changed = true;
LoopPhis.push_back(WidePhi);
}
}
WideIVMap.clear();
}
}