[Mesa-dev] [PATCH 4/7] nir/int64: Implement lowering of shift operations
Matt Turner
mattst88 at gmail.com
Sun Oct 14 22:11:34 UTC 2018
---
src/compiler/nir/nir.h | 1 +
src/compiler/nir/nir_lower_int64.c | 142 +++++++++++++++++++++++++++++++++++++
2 files changed, 143 insertions(+)
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 12cbd030e21..2c477126acc 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3001,6 +3001,7 @@ typedef enum {
nir_lower_ineg64 = (1 << 7),
nir_lower_logic64 = (1 << 8),
nir_lower_minmax64 = (1 << 9),
+ nir_lower_shift64 = (1 << 10),
} nir_lower_int64_options;
bool nir_lower_int64(nir_shader *shader, nir_lower_int64_options options);
diff --git a/src/compiler/nir/nir_lower_int64.c b/src/compiler/nir/nir_lower_int64.c
index 9cdc8a9d592..25882d3a858 100644
--- a/src/compiler/nir/nir_lower_int64.c
+++ b/src/compiler/nir/nir_lower_int64.c
@@ -90,6 +90,138 @@ lower_ixor64(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
nir_ixor(b, x_hi, y_hi));
}
+static nir_ssa_def *
+lower_ishl64(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
+{
+ /* Implemented as
+ *
+ * uint64_t lshift(uint64_t x, int c)
+ * {
+ * if (c == 0) return x;
+ *
+ * uint32_t lo = LO(x), hi = HI(x);
+ *
+ * if (c < 32) {
+ * uint32_t lo_shifted = lo << (c & 0x1f);
+ * uint32_t hi_shifted = hi << (c & 0x1f);
+ * uint32_t lo_shifted_hi = lo >> (abs(32 - c) & 0x1f);
+ * return pack_64(lo_shifted, hi_shifted | lo_shifted_hi);
+ * } else {
+ * uint32_t lo_shifted_hi = lo << (abs(32 - c) & 0x1f);
+ * return pack_64(0, lo_shifted_hi);
+ * }
+ * }
+ */
+ 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 *reverse_count = nir_iabs(b, nir_iadd(b, y, nir_imm_int(b, -32)));
+ nir_ssa_def *lo_shifted = nir_ishl(b, x_lo, y);
+ nir_ssa_def *hi_shifted = nir_ishl(b, x_hi, y);
+ nir_ssa_def *lo_shifted_hi = nir_ushr(b, x_lo, reverse_count);
+
+ nir_ssa_def *res_if_lt_32 =
+ nir_pack_64_2x32_split(b, lo_shifted,
+ nir_ior(b, hi_shifted, lo_shifted_hi));
+ nir_ssa_def *res_if_ge_32 =
+ nir_pack_64_2x32_split(b, nir_imm_int(b, 0),
+ nir_ishl(b, x_lo, reverse_count));
+
+ return nir_bcsel(b,
+ nir_ieq(b, y, nir_imm_int(b, 0)), x,
+ nir_bcsel(b, nir_uge(b, y, nir_imm_int(b, 32)),
+ res_if_ge_32, res_if_lt_32));
+}
+
+static nir_ssa_def *
+lower_ishr64(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
+{
+ /* Implemented as
+ *
+ * uint64_t arshift(uint64_t x, int c)
+ * {
+ * if (c == 0) return x;
+ *
+ * uint32_t lo = LO(x);
+ * int32_t hi = HI(x);
+ *
+ * if (c < 32) {
+ * uint32_t lo_shifted = lo >> (c & 0x1f);
+ * uint32_t hi_shifted = hi >> (c & 0x1f);
+ * uint32_t hi_shifted_lo = hi << (abs(32 - c) & 0x1f);
+ * return pack_64(hi_shifted, hi_shifted_lo | lo_shifted);
+ * } else {
+ * uint32_t hi_shifted = hi >> 31;
+ * uint32_t hi_shifted_lo = hi >> (abs(32 - c) & 0x1f);
+ * return pack_64(hi_shifted, hi_shifted_lo);
+ * }
+ * }
+ */
+ 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 *reverse_count = nir_iabs(b, nir_iadd(b, y, nir_imm_int(b, -32)));
+ nir_ssa_def *lo_shifted = nir_ushr(b, x_lo, y);
+ nir_ssa_def *hi_shifted = nir_ishr(b, x_hi, y);
+ nir_ssa_def *hi_shifted_lo = nir_ishl(b, x_hi, reverse_count);
+
+ nir_ssa_def *res_if_lt_32 =
+ nir_pack_64_2x32_split(b, nir_ior(b, lo_shifted, hi_shifted_lo),
+ hi_shifted);
+ nir_ssa_def *res_if_ge_32 =
+ nir_pack_64_2x32_split(b, nir_ishr(b, x_hi, reverse_count),
+ nir_ishr(b, x_hi, nir_imm_int(b, 31)));
+
+ return nir_bcsel(b,
+ nir_ieq(b, y, nir_imm_int(b, 0)), x,
+ nir_bcsel(b, nir_uge(b, y, nir_imm_int(b, 32)),
+ res_if_ge_32, res_if_lt_32));
+}
+
+static nir_ssa_def *
+lower_ushr64(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
+{
+ /* Implemented as
+ *
+ * uint64_t rshift(uint64_t x, int c)
+ * {
+ * if (c == 0) return x;
+ *
+ * uint32_t lo = LO(x), hi = HI(x);
+ *
+ * if (c < 32) {
+ * uint32_t lo_shifted = lo >> (c & 0x1f);
+ * uint32_t hi_shifted = hi >> (c & 0x1f);
+ * uint32_t hi_shifted_lo = hi << (abs(32 - c) & 0x1f);
+ * return pack_64(hi_shifted, hi_shifted_lo | lo_shifted);
+ * } else {
+ * uint32_t hi_shifted_lo = hi >> (abs(32 - c) & 0x1f);
+ * return pack_64(0, hi_shifted_lo);
+ * }
+ * }
+ */
+
+ 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 *reverse_count = nir_iabs(b, nir_iadd(b, y, nir_imm_int(b, -32)));
+ nir_ssa_def *lo_shifted = nir_ushr(b, x_lo, y);
+ nir_ssa_def *hi_shifted = nir_ushr(b, x_hi, y);
+ nir_ssa_def *hi_shifted_lo = nir_ishl(b, x_hi, reverse_count);
+
+ nir_ssa_def *res_if_lt_32 =
+ nir_pack_64_2x32_split(b, nir_ior(b, lo_shifted, hi_shifted_lo),
+ hi_shifted);
+ nir_ssa_def *res_if_ge_32 =
+ nir_pack_64_2x32_split(b, nir_ushr(b, x_hi, reverse_count),
+ nir_imm_int(b, 0));
+
+ return nir_bcsel(b,
+ nir_ieq(b, y, nir_imm_int(b, 0)), x,
+ nir_bcsel(b, nir_uge(b, y, nir_imm_int(b, 32)),
+ res_if_ge_32, res_if_lt_32));
+}
+
static nir_ssa_def *
lower_iadd64(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
{
@@ -430,6 +562,10 @@ opcode_to_options_mask(nir_op opcode)
case nir_op_ixor:
case nir_op_inot:
return nir_lower_logic64;
+ case nir_op_ishl:
+ case nir_op_ishr:
+ case nir_op_ushr:
+ return nir_lower_shift64;
default:
return 0;
}
@@ -492,6 +628,12 @@ lower_int64_alu_instr(nir_builder *b, nir_alu_instr *alu)
return lower_ixor64(b, src[0], src[1]);
case nir_op_inot:
return lower_inot64(b, src[0]);
+ case nir_op_ishl:
+ return lower_ishl64(b, src[0], src[1]);
+ case nir_op_ishr:
+ return lower_ishr64(b, src[0], src[1]);
+ case nir_op_ushr:
+ return lower_ushr64(b, src[0], src[1]);
default:
unreachable("Invalid ALU opcode to lower");
}
--
2.16.4
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