Merging r258325:

Merging r258325:
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r258325 | spatel | 2016-01-20 09:41:14 -0800 (Wed, 20 Jan 2016) | 21 lines

[LibCallSimplifier] don't get fooled by a fake sqrt()

The test case will crash without this patch because the subsequent call to
hasUnsafeAlgebra() assumes that the call instruction is an FPMathOperator
(ie, returns an FP type).

This part of the function signature check was omitted for the sqrt() case,
but seems to be in place for all other transforms.

Before:
http://reviews.llvm.org/rL257400
...we would have needlessly continued execution in optimizeSqrt(), but the
bug was harmless because we'd eventually fail some other check and return
without damage.

This should fix:
https://llvm.org/bugs/show_bug.cgi?id=26211

Differential Revision: http://reviews.llvm.org/D16198

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_38@258353 91177308-0d34-0410-b5e6-96231b3b80d8