Refine the definition of convergent to only disallow the addition of new control dependencies.
This covers the common case of operations that cannot be sunk.
Operations that cannot be hoisted should already be handled properly via
the safe-to-speculate rules and mechanisms.
llvm-svn: 249865
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index aa1b091..5e6d619 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -686,7 +686,8 @@
if (!MI->isSafeToMove(AA, SawStore))
return false;
- // Convergent operations may only be moved to control equivalent locations.
+ // Convergent operations may not be made control-dependent on additional
+ // values.
if (MI->isConvergent())
return false;