Merging r352539:

Merging r352539:
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r352539 | arsenm | 2019-01-29 21:49:47 +0100 (Tue, 29 Jan 2019) | 9 lines

Revert "OpenCL: Extend argument promotion rules to vector types"

This reverts r348083. This was based on a misreading of the spec
for printf specifiers.

Also revert r343653, as without a subsequent patch, a correctly
specified format for a vector will incorrectly warn.

Fixes bug 40491.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_80@352547 91177308-0d34-0410-b5e6-96231b3b80d8