Quite a few gcc.target/aarch64/sve/cond*.c tests started failing
after g:
68e0063397ba820e71adc220b2da0581dce29ffa, but it turns out
that we were cheating passes before the patch.
The tests involve comparing the cost of N wide compares, a pack
sequence, and a narrow COND_EXPR with the cost of a single COND_EXPR
on fewer elements. The costs for the former included all operations,
but the costs for the latter didn't model the comparison embedded in
the COND_EXPR. The patch made us include the comparison on both sides,
making it apples-for-apples, but that's enough to tip the balance in
favour of using the wider types.
I think the new choice does reflect the current SVE cost model
correctly. (Whether and how the model should be tweaked is a
different question.) This patch therefore changes the tuning
vector length to one that makes the choice more obvious.
That in turn needs a tweak to compare_inside_loop_cost.
The function compares body_cost1/vf1 with body_cost2/vf2,
but for fully-amsked loops, it limits vf to the actual number
of iterations. This is so that (say) an expensive 16-element
vector body doesn't win over a cheaper 8-element vector body
when there are only 7 elements to process.
However, the limit was applied using known_le, regardless of
the tuning target. For a heuristic like this, it seems better
to use the likely minimum (which is a concept that was only
added after this code went in).
g:
68e0063397ba820e71adc220b2da0581dce29ffa also fixed
vcond_4_costly.c.
gcc/
* tree-vectorizer.cc (vector_costs::compare_inside_loop_cost):
Use the likely minimum VF when bounding the denominators to
the estimated number of iterations.
gcc/testsuite/
* gcc.target/aarch64/sve/cond_asrd_1.c: Tune for a 256-bit
vector length.
* gcc.target/aarch64/sve/cond_cnot_4.c: Likewise.
* gcc.target/aarch64/sve/cond_cnot_6.c: Likewise.
* gcc.target/aarch64/sve/cond_unary_5.c: Likewise.
* gcc.target/aarch64/sve/cond_unary_6.c: Likewise.
* gcc.target/aarch64/sve/cond_uxt_5.c: Likewise.
* gcc.target/aarch64/sve/vcond_4_costly.c: Remove XFAILs.
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
/* { dg-do compile } */
-/* { dg-options "-O2 -ftree-vectorize" } */
+/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256" } */
#include <stdint.h>
TEST_CMP (nugt)
/* 2 each for: eq, ne, ueq, nueq. */
-/* { dg-final { scan-assembler-times {\tfcm(?:eq|ne)\tp[0-9]+\.s, p[0-7]/z, z[0-9]+\.s, z[0-9]+\.s\n} 8 { xfail *-*-* } } } */
-/* { dg-final { scan-assembler-times {\tfcm(?:eq|ne)\tp[0-9]+\.d, p[0-7]/z, z[0-9]+\.d, z[0-9]+\.d\n} 16 { xfail *-*-* } } } */
+/* { dg-final { scan-assembler-times {\tfcm(?:eq|ne)\tp[0-9]+\.s, p[0-7]/z, z[0-9]+\.s, z[0-9]+\.s\n} 8 } } */
+/* { dg-final { scan-assembler-times {\tfcm(?:eq|ne)\tp[0-9]+\.d, p[0-7]/z, z[0-9]+\.d, z[0-9]+\.d\n} 16 } } */
/* 2 each for: olt, ult, nult, ogt, ugt, nugt. */
/* { dg-final { scan-assembler-times {\tfcm[lg]t\tp[0-9]+\.s, p[0-7]/z, z[0-9]+\.s, z[0-9]+\.s\n} 12 } } */
HOST_WIDE_INT estimated_max_niter = likely_max_stmt_executions_int (loop);
if (estimated_max_niter != -1)
{
- if (known_le (estimated_max_niter, this_vf))
+ if (estimated_poly_value (this_vf, POLY_VALUE_MIN)
+ >= estimated_max_niter)
this_vf = estimated_max_niter;
- if (known_le (estimated_max_niter, other_vf))
+ if (estimated_poly_value (other_vf, POLY_VALUE_MIN)
+ >= estimated_max_niter)
other_vf = estimated_max_niter;
}