Fully-masked loops can be profitable even if the iteration
count is smaller than the vectorisation factor. In this case
we're effectively doing a complete unroll followed by SLP.
The documentation for min-vect-loop-bound says that the
default value was 0, but actually the default and minimum
were 1. We need it to be 0 for this case since the parameter
counts a whole number of vector iterations.
2018-01-13 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
gcc/
* doc/sourcebuild.texi (vect_fully_masked): Document.
* params.def (PARAM_MIN_VECT_LOOP_BOUND): Change minimum and
default value to 0.
* tree-vect-loop.c (vect_analyze_loop_costing): New function,
split out from...
(vect_analyze_loop_2): ...here. Don't check the vectorization
factor against the number of loop iterations if the loop is
fully-masked.
gcc/testsuite/
* lib/target-supports.exp (check_effective_target_vect_fully_masked):
New proc.
* gcc.dg/vect/slp-3.c: Expect all loops to be vectorized if
vect_fully_masked.
* gcc.target/aarch64/sve/loop_add_4.c: New test.
* gcc.target/aarch64/sve/loop_add_4_run.c: Likewise.
* gcc.target/aarch64/sve/loop_add_5.c: Likewise.
* gcc.target/aarch64/sve/loop_add_5_run.c: Likewise.
* gcc.target/aarch64/sve/miniloop_1.c: Likewise.
* gcc.target/aarch64/sve/miniloop_2.c: Likewise.
Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256629
