The following avoids re-analyzing the loop as epilogue when not
using partial vectors and the mode is the same as the autodetected
vector mode and that has a too high VF for a non-predicated loop.
This situation occurs almost always on x86 and saves us one
re-analysis unless --param vect-partial-vector-usage is non-default.
Bootstrap and regtest running on x86_64-unknown-linux-gnu, OK?
Thanks,
Richard.
* tree-vect-loop.cc (vect_analyze_loop): Prune epilogue
analysis further when not using partial vectors.
---
gcc/tree-vect-loop.cc | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index b91ef4a2325..d9091c6c705 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -3770,6 +3770,26 @@ vect_analyze_loop (class loop *loop, gimple
*loop_vectorized_call,
break;
continue;
}
+ /* We would need an exhaustive search to find all modes we
+ skipped but that would lead to the same result as another
+ and where we'd could check cached_vf_per_mode against.
+ Check for the autodetected mode, which is the common
+ situation on x86 which does not perform cost comparison. */
+ if (!supports_partial_vectors
+ && maybe_ge (cached_vf_per_mode[0], first_vinfo_vf)
+ && VECTOR_MODE_P (autodetected_vector_mode)
+ && (related_vector_mode (vector_modes[mode_i],
+ GET_MODE_INNER
(autodetected_vector_mode))
+ == autodetected_vector_mode)
+ && (related_vector_mode (autodetected_vector_mode,
+ GET_MODE_INNER (vector_modes[mode_i]))
+ == vector_modes[mode_i]))
+ {
+ mode_i++;
+ if (mode_i == vector_modes.length ())
+ break;
+ continue;
+ }
if (dump_enabled_p ())
dump_printf_loc (MSG_NOTE, vect_location,
--
2.43.0
