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authorRichard Sandiford <richard.sandiford@arm.com>2019-11-16 10:43:52 +0000
committerRichard Sandiford <rsandifo@gcc.gnu.org>2019-11-16 10:43:52 +0000
commiteb23241ba81aace0c881ccee4643632809741953 (patch)
tree7eec28a84e7f30c72a362aff3439e15219dcea7e /gcc/doc
parentbcc7e346bf9b5dc77797ea949d6adc740deb30ca (diff)
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[AArch64] Enable VECT_COMPARE_COSTS by default for SVE
This patch enables VECT_COMPARE_COSTS by default for SVE, both so that we can compare SVE against Advanced SIMD and so that (with future patches) we can compare multiple SVE vectorisation approaches against each other. It also adds a target-specific --param to control this. 2019-11-16 Richard Sandiford <richard.sandiford@arm.com> gcc/ * config/aarch64/aarch64.opt (--param=aarch64-sve-compare-costs): New option. * doc/invoke.texi: Document it. * config/aarch64/aarch64.c (aarch64_autovectorize_vector_modes): By default, return VECT_COMPARE_COSTS for SVE. gcc/testsuite/ * gcc.target/aarch64/sve/reduc_3.c: Split multi-vector cases out into... * gcc.target/aarch64/sve/reduc_3_costly.c: ...this new test, passing -fno-vect-cost-model for them. * gcc.target/aarch64/sve/slp_6.c: Add -fno-vect-cost-model. * gcc.target/aarch64/sve/slp_7.c, * gcc.target/aarch64/sve/slp_7_run.c: Split multi-vector cases out into... * gcc.target/aarch64/sve/slp_7_costly.c, * gcc.target/aarch64/sve/slp_7_costly_run.c: ...these new tests, passing -fno-vect-cost-model for them. * gcc.target/aarch64/sve/while_7.c: Add -fno-vect-cost-model. * gcc.target/aarch64/sve/while_9.c: Likewise. From-SVN: r278337
Diffstat (limited to 'gcc/doc')
-rw-r--r--gcc/doc/invoke.texi18
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index fe79ca2..7f19d67 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -11179,8 +11179,8 @@ without notice in future releases.
In order to get minimal, maximal and default value of a parameter,
one can use @option{--help=param -Q} options.
-In each case, the @var{value} is an integer. The allowable choices for
-@var{name} are:
+In each case, the @var{value} is an integer. The following choices
+of @var{name} are recognized for all targets:
@table @gcctabopt
@item predictable-branch-outcome
@@ -12396,6 +12396,20 @@ statements or when determining their validity prior to issuing
diagnostics.
@end table
+
+The following choices of @var{name} are available on AArch64 targets:
+
+@table @gcctabopt
+@item aarch64-sve-compare-costs
+When vectorizing for SVE, consider using ``unpacked'' vectors for
+smaller elements and use the cost model to pick the cheapest approach.
+Also use the cost model to choose between SVE and Advanced SIMD vectorization.
+
+Using unpacked vectors includes storing smaller elements in larger
+containers and accessing elements with extending loads and truncating
+stores.
+@end table
+
@end table
@node Instrumentation Options