Cherry-pick r260441 and r263310 from upstream LLVM. These changes fix CFI bad-cast errors. Bug: 469376 Change-Id: I3bb0cffa360b979845d203f87a2026658acca7e4 Reviewed-on: https://chromium-review.googlesource.com/757856 Reviewed-by: agrieve <agrieve@chromium.org> Tested-by: agrieve <agrieve@chromium.org>