search for: getscevimpl

Displaying 9 results from an estimated 9 matches for "getscevimpl".

2018 Feb 11
2
[SCEV] Inconsistent SCEV formation for zext
...om the internal recursive calls for setting/resetting the state correctly. We start with adding the most conservative result for the value in PendingCache. This would be getUnknown() for getSCEV(). So getSCEV() may be implemented something like this- ScalarEvolution::getSCEV(Value *V) { return getSCEVImpl(V, true); } ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { // Look up in cache using logic described above If (S = getExistingSCEV()) return S; if (IsTopCall) { PessimisticMode = false; PendingCache.clear(); PendingCache.insert(V, getUnknown(V)); } SCEV...
2018 Feb 20
0
[SCEV] Inconsistent SCEV formation for zext
...ive calls for setting/resetting the state correctly. We start with adding the most conservative result for the value in PendingCache. This would be getUnknown() for getSCEV(). > > So getSCEV() may be implemented something like this- > > ScalarEvolution::getSCEV(Value *V) { > return getSCEVImpl(V, true); > } > > ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { > // Look up in cache using logic described above > If (S = getExistingSCEV()) > return S; > > if (IsTopCall) { > PessimisticMode = false; > PendingCache.clear(); >...
2018 Feb 10
0
[SCEV] Inconsistent SCEV formation for zext
Hi, +CC Max, Serguei This looks like a textbook case of why caching is hard. We first call getZeroExtendExpr on %dec, and this call does end up returning an add rec. However, in the process of simplifying the zext, it also calls into isLoopBackedgeGuardedByCond which in turn calls getZeroExtendExpr(%dec) again. However, this second (recursive) time, we don't simplify the zext and cache a
2018 Feb 26
2
[SCEV] Inconsistent SCEV formation for zext
...EV(LoopIV) -> getBackedgeTakenInfo(Loop) This is handled correctly because we have some logic to forget loop header phi entries. Under the new setup, we would not have to 'special case' this logic. It will be handled by the same 'IsTopCall' approach. > > ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { > // Look up in cache using logic described above > If (S = getExistingSCEV()) > return S; > > if (IsTopCall) { > PessimisticMode = false; > PendingCache.clear(); > PendingCache.insert(V, getUnknown(V)); >> Can...
2018 Feb 08
2
[SCEV] Inconsistent SCEV formation for zext
Hi Sanjoy, SCEV is behaving inconsistently when forming SCEV for this zext instruction in the attached test case- %conv5 = zext i32 %dec to i64 If we request a SCEV for the instruction, it returns- (zext i32 {{-1,+,1}<nw><%for.body>,+,-1}<nw><%for.body7> to i64) This can be seen by invoking- $ opt -analyze -scalar-evolution inconsistent-scev-zext.ll But when computing
2018 Mar 13
2
[SCEV] Inconsistent SCEV formation for zext
...BackedgeTakenInfo(Loop) > > This is handled correctly because we have some logic to forget loop header phi entries. Under the new setup, we would not have to 'special case' this logic. It will be handled by the same 'IsTopCall' approach. > >> >> ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { >> // Look up in cache using logic described above >> If (S = getExistingSCEV()) >> return S; >> >> if (IsTopCall) { >> PessimisticMode = false; >> PendingCache.clear(); >> PendingCache.insert(V...
2018 Mar 12
0
[SCEV] Inconsistent SCEV formation for zext
...EV(LoopIV) -> getBackedgeTakenInfo(Loop) This is handled correctly because we have some logic to forget loop header phi entries. Under the new setup, we would not have to 'special case' this logic. It will be handled by the same 'IsTopCall' approach. > > ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { > // Look up in cache using logic described above > If (S = getExistingSCEV()) > return S; > > if (IsTopCall) { > PessimisticMode = false; > PendingCache.clear(); > PendingCache.insert(V, getUnknown(V)); >> Can...
2018 Mar 13
0
[SCEV] Inconsistent SCEV formation for zext
...BackedgeTakenInfo(Loop) > > This is handled correctly because we have some logic to forget loop header phi entries. Under the new setup, we would not have to 'special case' this logic. It will be handled by the same 'IsTopCall' approach. > >> >> ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { >> // Look up in cache using logic described above >> If (S = getExistingSCEV()) >> return S; >> >> if (IsTopCall) { >> PessimisticMode = false; >> PendingCache.clear(); >> PendingCache.insert(V...
2018 Mar 13
1
[SCEV] Inconsistent SCEV formation for zext
...op) >> >> This is handled correctly because we have some logic to forget loop header phi entries. Under the new setup, we would not have to 'special case' this logic. It will be handled by the same 'IsTopCall' approach. >> >>> >>> ScalarEvolution::getSCEVImpl (Value *V, bool IsTopCall = false) { >>> // Look up in cache using logic described above >>> If (S = getExistingSCEV()) >>> return S; >>> >>> if (IsTopCall) { >>> PessimisticMode = false; >>> PendingCache.clear(); >&...