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[NewGVN] Fixup store count for the `initial` congruency class. 

It was always zero. When we move a store from `initial` to its
own congruency class, we end up with a negative store count, which
is obviously wrong.
Also, while here, change StoreCount to be signed so that the assertions
actually fire.

Ack'ed by Daniel Berlin.

llvm-svn: 291725
This commit is contained in:
Davide Italiano 2017-01-11 23:41:24 +00:00
parent 629cb7d8cc
commit eac05f6b88
1 changed files with 6 additions and 3 deletions
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9
llvm/lib/Transforms/Scalar/NewGVN.cpp
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@ -137,7 +137,7 @@ struct CongruenceClass {
// Number of stores in this congruence class.
// This is used so we can detect store equivalence changes properly.
unsigned StoreCount = 0;
int StoreCount = 0;
explicit CongruenceClass(unsigned ID) : ID(ID) {}
CongruenceClass(unsigned ID, Value *Leader, const Expression *E)
@ -1066,7 +1066,7 @@ void NewGVN::moveValueToNewCongruenceClass(Value *V, CongruenceClass *OldClass,
--OldClass->StoreCount;
assert(OldClass->StoreCount >= 0);
++NewClass->StoreCount;
assert(NewClass->StoreCount >= 0);
assert(NewClass->StoreCount > 0);
}
ValueToClass[V] = NewClass;
@ -1337,9 +1337,12 @@ void NewGVN::initializeCongruenceClasses(Function &F) {
// MemoryDef's for stores and all MemoryPhis to be equal. Right now, no
// other expression can generate a memory equivalence. If we start
// handling memcpy/etc, we can expand this.
if (isa<StoreInst>(&I))
if (isa<StoreInst>(&I)) {
MemoryAccessEquiv.insert(
{MSSA->getMemoryAccess(&I), MSSA->getLiveOnEntryDef()});
++InitialClass->StoreCount;
assert(InitialClass->StoreCount > 0);
}
}
}
InitialClass->Members.swap(InitialValues);