[X86] Don't alter HasOpaqueSPAdjustment after we've relied on it
We rely on HasOpaqueSPAdjustment not changing after we've calculated
things based on it. Things like whether or not we can use 'rep;movs' to
copy bytes around, that sort of thing. If it changes, invariants in the
backend will quietly break. This situation arose when we had a call to
memcpy *and* a COPY of the FLAGS register where we would attempt to
reference local variables using %esi, a register that was clobbered by
the 'rep;movs'.
This fixes PR26124.
llvm-svn: 257730
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 9f8759d..c075da4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -634,7 +634,7 @@
}
if (TLI->hasCopyImplyingStackAdjustment(MF))
- MFI->setHasOpaqueSPAdjustment(true);
+ MFI->setHasCopyImplyingStackAdjustment(true);
// Freeze the set of reserved registers now that MachineFrameInfo has been
// set up. All the information required by getReservedRegs() should be