Merging r340417:

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r340417 | hakzsam | 2018-08-22 18:08:48 +0200 (Wed, 22 Aug 2018) | 14 lines

AMDGPU: bump AS.MAX_COMMON_ADDRESS to 6 since 32-bit addr space

32-bit constant address space is declared as 6, so the
maximum number of address spaces is 6, not 5.

Fixes "LLVM ERROR: Pointer address space out of range".

v5: rename MAX_COMMON_ADDRESS to MAX_AMDGPU_ADDRESS
v4: - fix compilation issues
    - fix out of bounds access
v3: use static_assert()
v2: add a very simple test for 32-bit addr space

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106630
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@341041 91177308-0d34-0410-b5e6-96231b3b80d8