[MemorySSA] Define a restricted upward AccessList splice.
Differential Revision: https://reviews.llvm.org/D26661
llvm-svn: 290527
diff --git a/llvm/lib/Transforms/Utils/MemorySSA.cpp b/llvm/lib/Transforms/Utils/MemorySSA.cpp
index c887f86..1ce4225 100644
--- a/llvm/lib/Transforms/Utils/MemorySSA.cpp
+++ b/llvm/lib/Transforms/Utils/MemorySSA.cpp
@@ -1623,6 +1623,29 @@
return NewAccess;
}
+void MemorySSA::spliceMemoryAccessAbove(MemoryDef *Where,
+ MemoryUseOrDef *What) {
+ assert(What != getLiveOnEntryDef() &&
+ Where != getLiveOnEntryDef() && "Can't splice (above) LOE.");
+ assert(dominates(Where, What) && "Only upwards splices are permitted.");
+
+ if (Where == What)
+ return;
+ if (isa<MemoryDef>(What)) {
+ // TODO: possibly use removeMemoryAccess' more efficient RAUW
+ What->replaceAllUsesWith(What->getDefiningAccess());
+ What->setDefiningAccess(Where->getDefiningAccess());
+ Where->setDefiningAccess(What);
+ }
+ AccessList *Src = getWritableBlockAccesses(What->getBlock());
+ AccessList *Dest = getWritableBlockAccesses(Where->getBlock());
+ Dest->splice(AccessList::iterator(Where), *Src, What);
+
+ BlockNumberingValid.erase(What->getBlock());
+ if (What->getBlock() != Where->getBlock())
+ BlockNumberingValid.erase(Where->getBlock());
+}
+
/// \brief Helper function to create new memory accesses
MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I) {
// The assume intrinsic has a control dependency which we model by claiming