Merging r313675:

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r313675 | rcraik | 2017-09-19 14:04:23 -0700 (Tue, 19 Sep 2017) | 9 lines

[OpenMP] fix seg-faults printing diagnostics with invalid ordered(n) values

When the value specified for n in ordered(n) is larger than the number of loops a segmentation fault can occur in one of two ways when attempting to print out a diagnostic for an associated depend(sink : vec):
1) The iteration vector vec contains less than n items
2) The iteration vector vec contains a variable that is not a loop control variable
This patch addresses both of these issues.

Differential Revision: https://reviews.llvm.org/D38049

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llvm-svn: 318116