Fix a logic bug in inline expansion of memcpy / memset with an overlapping
load / store pair. It's not legal to use a wider load than the size of
the remaining bytes if it's the first pair of load / store.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170018 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 269f221..2375182 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3469,9 +3469,6 @@
unsigned NumMemOps = 0;
while (Size != 0) {
- if (++NumMemOps > Limit)
- return false;
-
unsigned VTSize = VT.getSizeInBits() / 8;
while (VTSize > Size) {
// For now, only use non-vector load / store's for the left-over pieces.
@@ -3507,7 +3504,8 @@
// FIXME: Only does this for 64-bit or more since we don't have proper
// cost model for unaligned load / store.
bool Fast;
- if (AllowOverlap && VTSize >= 8 && NewVTSize < Size &&
+ if (NumMemOps && AllowOverlap &&
+ VTSize >= 8 && NewVTSize < Size &&
TLI.allowsUnalignedMemoryAccesses(VT, &Fast) && Fast)
VTSize = Size;
else {
@@ -3516,6 +3514,9 @@
}
}
+ if (++NumMemOps > Limit)
+ return false;
+
MemOps.push_back(VT);
Size -= VTSize;
}