[PATCH] vect/test: Don't check for epilogue loop [PR97075]

[Segher Boessenkool]

On Fri, Sep 18, 2020 at 10:37:47AM +0800, Kewen.Lin wrote:
> The commit r11-3230 brings a nice improvement to use full
> vectors instead of partial vectors when available.  But
> it caused some vector with length test cases to fail on
> Power.
> 
> The failure on gcc.target/powerpc/p9-vec-length-epil-7.c
> exposed one issue that: we call function 
> vect_need_peeling_or_partial_vectors_p in function
> vect_analyze_loop_2, since it's in analysis phase, for
> the epilogue loop, we could get the wrong information like
> LOOP_VINFO_INT_NITERS (loop_vinfo), further get the wrong
> answer for vect_need_peeling_or_partial_vectors_p.
> For the epilogue loop in this failure specific, the niter
> that we get is 58 (should be 1), vf is 2.
> 
> For epilogue loop with partial vectors, it would use the
> same VF as the main loop, so it won't be able to use full
> vector, this patch is to exclude epilogue loop for the
> check vect_need_peeling_or_partial_vectors_p in
> vect_analyze_loop_2.
> 
> The failure on gcc.target/powerpc/p9-vec-length-full-6.c
> is just a test issue, the 64bit/32bit pairs are able to
> use full vector, fixed in the patch accordingly.

> gcc/ChangeLog:
> 
> 	* tree-vect-loop.c (vect_analyze_loop_2): Don't check
> 	vect_need_peeling_or_partial_vectors_p for the epilogue loop.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/powerpc/p9-vec-length-full-6.c: Adjust.

The testcase part of course is okay for trunk, if this is the expected
(and good :-) ) code.Thanks,


Segher