Vectorizer generates useless vector.memcheck block

[Quuxplusone]

Bugzilla Link	PR19651
Status	NEW
Importance	P normal
Reported by	Nicola Gigante (nicola.gigante@gmail.com)
Reported on	2014-05-04 06:45:16 -0700
Last modified on	2014-05-05 03:18:09 -0700
Version	trunk
Hardware	PC MacOS X
CC	dsaritz@gmail.com, hfinkel@anl.gov, llvm-bugs@lists.llvm.org, rengolin@gmail.com, zinovy.nis@gmail.com
Fixed by commit(s)
Attachments	testcase.cpp (847 bytes, application/octet-stream)
Blocks
Blocked by
See also

Created attachment 12474
Test source code

In the attached code, TBAA correctly recognize the pointers being of different
type, but the vectorizer emits anyway the vector.memcheck block to check if the
buffers overlap.

This happens even in the second part of the attached source code, where the
inputs are not pointers but std::array objects of different element types. The
input arrays are passed by value but the vectorizer still checks for
overlapping buffers.

In a pure compliant C++ context (so no 'restrict' keyword) it seems impossible
to tell the optimizer that I know my arrays won't overlap...

[Quuxplusone]

Attached testcase.cpp (847 bytes, application/octet-stream): Test source code

[Quuxplusone]

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