Fixup r364512
Fixup r364512

Fix stack-use-after-scope errors from r364512. One instance was already
fixed in r364611 - this patch simplifies that fix and addresses one more
instance of similar code.

Discussed in: https://reviews.llvm.org/D63905

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@364778 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm