[RegAlloc] Check that subreg liveness tracking applies to given virtual reg

Subregister liveness applies selectively to register classes with certain
properties. Make sure that when it's enabled, it applies to a given virtual
register (in virtual register rewriter).

llvm-svn: 339784

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index 0ead2b8340a..ed7bef667e7 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -525,7 +525,7 @@ void VirtRegRewriter::rewrite() {
         // Preserve semantics of sub-register operands.
         unsigned SubReg = MO.getSubReg();
         if (SubReg != 0) {
-          if (NoSubRegLiveness) {
+          if (NoSubRegLiveness || !MRI->shouldTrackSubRegLiveness(VirtReg)) {
             // A virtual register kill refers to the whole register, so we may
             // have to add implicit killed operands for the super-register.  A
             // partial redef always kills and redefines the super-register.