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.
2022-03-11 Richard Biener <rguenther@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.
- /* 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. */
/* 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)
/* 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 ();