After accounting for GPR -> XMM move cost for vec_construct the
base cost needs adjustments to not double-cost those. This also
lowers the cost when such move is not necessary.
This fixes the observed 538.imagick_r and 525.x264_r regressions
for me on Zen2 with -Ofast -march=native.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
OK for trunk?
Thanks,
Richard.
2022-03-11 Richard Biener <rguent...@suse.de>
PR target/104762
* config/i386/i386.cc (ix86_builtin_vectorization_cost): Do not
cost the first lane of SSE pieces as inserts for vec_construct.
---
gcc/config/i386/i386.cc | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 4121f986221..23bedea92bd 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -22597,16 +22597,21 @@ ix86_builtin_vectorization_cost (enum
vect_cost_for_stmt type_of_cost,
case vec_construct:
{
- /* N element inserts into SSE vectors. */
- int cost = TYPE_VECTOR_SUBPARTS (vectype) * ix86_cost->sse_op;
+ int n = TYPE_VECTOR_SUBPARTS (vectype);
+ /* N - 1 element inserts into an SSE vector, the possible
+ GPR -> XMM move is accounted for in add_stmt_cost. */
+ if (GET_MODE_BITSIZE (mode) <= 128)
+ return (n - 1) * ix86_cost->sse_op;
/* One vinserti128 for combining two SSE vectors for AVX256. */
- if (GET_MODE_BITSIZE (mode) == 256)
- cost += ix86_vec_cost (mode, ix86_cost->addss);
+ else if (GET_MODE_BITSIZE (mode) == 256)
+ return ((n - 2) * ix86_cost->sse_op
+ + ix86_vec_cost (mode, ix86_cost->addss));
/* One vinserti64x4 and two vinserti128 for combining SSE
and AVX256 vectors to AVX512. */
else if (GET_MODE_BITSIZE (mode) == 512)
- cost += 3 * ix86_vec_cost (mode, ix86_cost->addss);
- return cost;
+ return ((n - 4) * ix86_cost->sse_op
+ + 3 * ix86_vec_cost (mode, ix86_cost->addss));
+ gcc_unreachable ();
}
default:
--
2.34.1
