Mesa (master): nir: add 64-bit ufind_msb lowering support. (v2)
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Thu Nov 21 19:18:07 UTC 2019
Module: Mesa
Branch: master
Commit: d0d96053e6b7ce8bf2335ab3efb3e6d68eedcf28
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=d0d96053e6b7ce8bf2335ab3efb3e6d68eedcf28
Author: Dave Airlie <airlied at redhat.com>
Date: Wed Nov 20 09:23:14 2019 +1000
nir: add 64-bit ufind_msb lowering support. (v2)
This adds the option to lower 64-bit ufind_msb opcodes.
v2: use split_x/y removes component loops (Jason)
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
---
src/compiler/nir/nir.h | 1 +
src/compiler/nir/nir_lower_int64.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index e88d3f8df96..bae8c821243 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2622,6 +2622,7 @@ typedef enum {
nir_lower_shift64 = (1 << 11),
nir_lower_imul_2x32_64 = (1 << 12),
nir_lower_extract64 = (1 << 13),
+ nir_lower_ufind_msb64 = (1 << 14),
} nir_lower_int64_options;
typedef enum {
diff --git a/src/compiler/nir/nir_lower_int64.c b/src/compiler/nir/nir_lower_int64.c
index 72745134308..6e3f8526f7b 100644
--- a/src/compiler/nir/nir_lower_int64.c
+++ b/src/compiler/nir/nir_lower_int64.c
@@ -657,6 +657,19 @@ lower_extract(nir_builder *b, nir_op op, nir_ssa_def *x, nir_ssa_def *c)
return lower_u2u64(b, extract32);
}
+static nir_ssa_def *
+lower_ufind_msb64(nir_builder *b, nir_ssa_def *x)
+{
+
+ nir_ssa_def *x_lo = nir_unpack_64_2x32_split_x(b, x);
+ nir_ssa_def *x_hi = nir_unpack_64_2x32_split_y(b, x);
+ nir_ssa_def *lo_count = nir_ufind_msb(b, x_lo);
+ nir_ssa_def *hi_count = nir_ufind_msb(b, x_hi);
+ nir_ssa_def *valid_hi_bits = nir_ine(b, x_hi, nir_imm_int(b, 0));
+ nir_ssa_def *hi_res = nir_iadd(b, nir_imm_intN_t(b, 32, 32), hi_count);
+ return nir_bcsel(b, valid_hi_bits, hi_res, lo_count);
+}
+
nir_lower_int64_options
nir_lower_int64_op_to_options_mask(nir_op opcode)
{
@@ -718,6 +731,8 @@ nir_lower_int64_op_to_options_mask(nir_op opcode)
case nir_op_extract_u16:
case nir_op_extract_i16:
return nir_lower_extract64;
+ case nir_op_ufind_msb:
+ return nir_lower_ufind_msb64;
default:
return 0;
}
@@ -819,6 +834,9 @@ lower_int64_alu_instr(nir_builder *b, nir_instr *instr, void *_state)
case nir_op_extract_u16:
case nir_op_extract_i16:
return lower_extract(b, alu->op, src[0], src[1]);
+ case nir_op_ufind_msb:
+ return lower_ufind_msb64(b, src[0]);
+ break;
default:
unreachable("Invalid ALU opcode to lower");
}
@@ -864,6 +882,11 @@ should_lower_int64_alu_instr(const nir_instr *instr, const void *_options)
if (alu->src[0].src.ssa->bit_size != 64)
return false;
break;
+ case nir_op_ufind_msb:
+ assert(alu->src[0].src.is_ssa);
+ if (alu->src[0].src.ssa->bit_size != 64)
+ return false;
+ break;
default:
assert(alu->dest.dest.is_ssa);
if (alu->dest.dest.ssa.bit_size != 64)
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