Mesa (staging/19.0): nir/builder: Add a vector extract helper
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Mon Mar 18 18:51:24 UTC 2019
Module: Mesa
Branch: staging/19.0
Commit: fa137cd655c901fdcfe3fc2d2dab1dae86e0b3e8
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=fa137cd655c901fdcfe3fc2d2dab1dae86e0b3e8
Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date: Mon Mar 11 18:58:24 2019 -0500
nir/builder: Add a vector extract helper
This one's a tiny bit better than what we had in spirv_to_nir because it
emits a binary tree rather than a linear walk. It also doesn't leave
around unneeded bcsel instructions for a constant index and returns an
undef for constant OOB access.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira at intel.com>
(cherry picked from commit fe9a6c0f14aa3ca6dfb1c7480871c95838b5cf14)
---
src/compiler/nir/nir_builder.h | 29 +++++++++++++++++++++++++++++
src/compiler/spirv/spirv_to_nir.c | 7 +------
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index 2a36eb3c91b..101bc7ad637 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -561,6 +561,35 @@ nir_channels(nir_builder *b, nir_ssa_def *def, nir_component_mask_t mask)
}
static inline nir_ssa_def *
+_nir_vector_extract_helper(nir_builder *b, nir_ssa_def *vec, nir_ssa_def *c,
+ unsigned start, unsigned end)
+{
+ if (start == end - 1) {
+ return nir_channel(b, vec, start);
+ } else {
+ unsigned mid = start + (end - start) / 2;
+ return nir_bcsel(b, nir_ilt(b, c, nir_imm_int(b, mid)),
+ _nir_vector_extract_helper(b, vec, c, start, mid),
+ _nir_vector_extract_helper(b, vec, c, mid, end));
+ }
+}
+
+static inline nir_ssa_def *
+nir_vector_extract(nir_builder *b, nir_ssa_def *vec, nir_ssa_def *c)
+{
+ nir_src c_src = nir_src_for_ssa(c);
+ if (nir_src_is_const(c_src)) {
+ unsigned c_const = nir_src_as_uint(c_src);
+ if (c_const < vec->num_components)
+ return nir_channel(b, vec, c_const);
+ else
+ return nir_ssa_undef(b, 1, vec->bit_size);
+ } else {
+ return _nir_vector_extract_helper(b, vec, c, 0, vec->num_components);
+ }
+}
+
+static inline nir_ssa_def *
nir_i2i(nir_builder *build, nir_ssa_def *x, unsigned dest_bit_size)
{
if (x->bit_size == dest_bit_size)
diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index 770460115ca..f91b5e1019c 100644
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -3045,12 +3045,7 @@ nir_ssa_def *
vtn_vector_extract_dynamic(struct vtn_builder *b, nir_ssa_def *src,
nir_ssa_def *index)
{
- nir_ssa_def *dest = vtn_vector_extract(b, src, 0);
- for (unsigned i = 1; i < src->num_components; i++)
- dest = nir_bcsel(&b->nb, nir_ieq_imm(&b->nb, index, i),
- vtn_vector_extract(b, src, i), dest);
-
- return dest;
+ return nir_vector_extract(&b->nb, src, nir_i2i(&b->nb, index, 32));
}
nir_ssa_def *
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