The following happens to improve compile-time of the PR103641
testcase on aarch64 significantly. I did not investigate the
effect on the generated code but at least in theory
choose_mult_variant should do a better job when we tell it
the actual mode we are going to use for the operations it
synthesizes.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
OK for trunk?
Thanks,
Richard.
2022-02-04 Richard Biener <rguent...@suse.de>
PR tree-optimization/103641
* tree-vect-patterns.cc (vect_synth_mult_by_constant):
Pass the vector mode to choose_mult_variant.
---
gcc/tree-vect-patterns.cc | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index bea04992160..686a10caec1 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -3046,17 +3046,17 @@ vect_synth_mult_by_constant (vec_info *vinfo, tree op,
tree val,
can synthesize shifts that way. */
bool synth_shift_p = !vect_supportable_shift (vinfo, LSHIFT_EXPR, multtype);
+ tree vectype = get_vectype_for_scalar_type (vinfo, multtype);
HOST_WIDE_INT hwval = tree_to_shwi (val);
/* Use MAX_COST here as we don't want to limit the sequence on rtx costs.
The vectorizer's benefit analysis will decide whether it's beneficial
to do this. */
- bool possible = choose_mult_variant (mode, hwval, &alg,
- &variant, MAX_COST);
+ bool possible = choose_mult_variant (VECTOR_MODE_P (TYPE_MODE (vectype))
+ ? TYPE_MODE (vectype) : mode,
+ hwval, &alg, &variant, MAX_COST);
if (!possible)
return NULL;
- tree vectype = get_vectype_for_scalar_type (vinfo, multtype);
-
if (!vectype
|| !target_supports_mult_synth_alg (&alg, variant,
vectype, synth_shift_p))
--
2.34.1
