[eigen-commits] commit/eigen: benoitjacob: do not read buffers out of bounds -- load only the 4 bytes we know exist here. Could also have done a vld1_lane_f32 but doing so here, without the overhead of initializing the unused lane, would have triggered used-of-uninitialized-value errors in tools such as ASan. Note that this code is sub-optimal before or after this change: we should be reading either 2 or 4 float32 values per load-instruction (2 for ARM in-order cores with an affinity for 8-byte loads; 4 for ARM out-of-order cores able to dual-issue 16-byte load instructions with arithmetic instructions). Before or after this patch, we are only loading 4 bytes of useful data here (even if before this patch, we were technically loading 8, only to use only the 4 first).

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1 new commit in eigen:

https://bitbucket.org/eigen/eigen/commits/b8d3f548a9d9/
Changeset:   b8d3f548a9d9
User:        benoitjacob
Date:        2018-11-27 21:53:14+00:00
Summary:     do not read buffers out of bounds -- load only the 4 bytes we know exist here.  Could also have done a vld1_lane_f32 but doing so here, without the overhead of initializing the unused lane, would have triggered used-of-uninitialized-value errors in tools such as ASan.  Note that this code is sub-optimal before or after this change: we should be reading either 2 or 4 float32 values per load-instruction  (2 for ARM in-order cores with an affinity for 8-byte loads;  4 for ARM out-of-order cores able to dual-issue 16-byte load instructions with arithmetic instructions).  Before or after this patch, we are only loading 4 bytes of useful data here (even if before this patch, we were technically loading 8, only to use only the 4 first).
Affected #:  1 file

Repository URL: https://bitbucket.org/eigen/eigen/

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