[CUDA][HIP] Re-apply part of r372318.

- r372318 causes violation of `use-of-uninitialized-value` detected by
  MemorySanitizer. Once `Viable` field is set to false, `FailureKind`
  needs setting as well as it will be checked during destruction if
  `Viable` is not true.
- Revert the part trying to skip `std::vector` erasing.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372356 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 9cf778f934..6887cdd7ee 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -9422,13 +9422,15 @@ OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
     const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
     bool ContainsSameSideCandidate =
         llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
-          return Cand->Function &&
+          // Check viable function only.
+          return Cand->Viable && Cand->Function &&
                  S.IdentifyCUDAPreference(Caller, Cand->Function) ==
                      Sema::CFP_SameSide;
         });
     if (ContainsSameSideCandidate) {
       auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
-        return Cand->Function &&
+        // Check viable function only to avoid unnecessary data copying/moving.
+        return Cand->Viable && Cand->Function &&
                S.IdentifyCUDAPreference(Caller, Cand->Function) ==
                    Sema::CFP_WrongSide;
       };