[Mesa-dev] [PATCH 1/3] amd/common: add ac_build_opencoded_fetch_format
Nicolai Hähnle
nhaehnle at gmail.com
Thu Apr 25 11:18:16 UTC 2019
From: Nicolai Hähnle <nicolai.haehnle at amd.com>
Implement software emulation of buffer_load_format for all types required
by vertex buffer fetches.
---
src/amd/common/ac_llvm_build.c | 313 +++++++++++++++++++++++++++++++++
src/amd/common/ac_llvm_build.h | 30 ++++
2 files changed, 343 insertions(+)
diff --git a/src/amd/common/ac_llvm_build.c b/src/amd/common/ac_llvm_build.c
index 4fdf73c99ba..197c58a8e45 100644
--- a/src/amd/common/ac_llvm_build.c
+++ b/src/amd/common/ac_llvm_build.c
@@ -1667,20 +1667,333 @@ ac_build_tbuffer_load_byte(struct ac_llvm_context *ctx,
res = ac_build_raw_tbuffer_load(ctx, rsrc, voffset, soffset,
immoffset, 1, dfmt, nfmt, glc, false,
false);
res = LLVMBuildTrunc(ctx->builder, res, ctx->i8, "");
}
return res;
}
+
+/**
+ * Convert an 11- or 10-bit unsigned floating point number to an f32.
+ *
+ * The input exponent is expected to be biased analogous to IEEE-754, i.e. by
+ * 2^(exp_bits-1) - 1 (as defined in OpenGL and other graphics APIs).
+ */
+static LLVMValueRef
+ac_ufN_to_float(struct ac_llvm_context *ctx, LLVMValueRef src, unsigned exp_bits, unsigned mant_bits)
+{
+ assert(LLVMTypeOf(src) == ctx->i32);
+
+ LLVMValueRef tmp;
+ LLVMValueRef mantissa;
+ mantissa = LLVMBuildAnd(ctx->builder, src, LLVMConstInt(ctx->i32, (1 << mant_bits) - 1, false), "");
+
+ /* Converting normal numbers is just a shift + correcting the exponent bias */
+ unsigned normal_shift = 23 - mant_bits;
+ unsigned bias_shift = 127 - ((1 << (exp_bits - 1)) - 1);
+ LLVMValueRef shifted, normal;
+
+ shifted = LLVMBuildShl(ctx->builder, src, LLVMConstInt(ctx->i32, normal_shift, false), "");
+ normal = LLVMBuildAdd(ctx->builder, shifted, LLVMConstInt(ctx->i32, bias_shift << 23, false), "");
+
+ /* Converting nan/inf numbers is the same, but with a different exponent update */
+ LLVMValueRef naninf;
+ naninf = LLVMBuildOr(ctx->builder, normal, LLVMConstInt(ctx->i32, 0xff << 23, false), "");
+
+ /* Converting denormals is the complex case: determine the leading zeros of the
+ * mantissa to obtain the correct shift for the mantissa and exponent correction.
+ */
+ LLVMValueRef denormal;
+ LLVMValueRef params[2] = {
+ mantissa,
+ ctx->i1true, /* result can be undef when arg is 0 */
+ };
+ LLVMValueRef ctlz = ac_build_intrinsic(ctx, "llvm.ctlz.i32", ctx->i32,
+ params, 2, AC_FUNC_ATTR_READNONE);
+
+ /* Shift such that the leading 1 ends up as the LSB of the exponent field. */
+ tmp = LLVMBuildSub(ctx->builder, ctlz, LLVMConstInt(ctx->i32, 8, false), "");
+ denormal = LLVMBuildShl(ctx->builder, mantissa, tmp, "");
+
+ unsigned denormal_exp = bias_shift + (32 - mant_bits) - 1;
+ tmp = LLVMBuildSub(ctx->builder, LLVMConstInt(ctx->i32, denormal_exp, false), ctlz, "");
+ tmp = LLVMBuildShl(ctx->builder, tmp, LLVMConstInt(ctx->i32, 23, false), "");
+ denormal = LLVMBuildAdd(ctx->builder, denormal, tmp, "");
+
+ /* Select the final result. */
+ LLVMValueRef result;
+
+ tmp = LLVMBuildICmp(ctx->builder, LLVMIntUGE, src,
+ LLVMConstInt(ctx->i32, ((1 << exp_bits) - 1) << mant_bits, false), "");
+ result = LLVMBuildSelect(ctx->builder, tmp, naninf, normal, "");
+
+ tmp = LLVMBuildICmp(ctx->builder, LLVMIntUGE, src,
+ LLVMConstInt(ctx->i32, 1 << mant_bits, false), "");
+ result = LLVMBuildSelect(ctx->builder, tmp, result, denormal, "");
+
+ tmp = LLVMBuildICmp(ctx->builder, LLVMIntNE, src, ctx->i32_0, "");
+ result = LLVMBuildSelect(ctx->builder, tmp, result, ctx->i32_0, "");
+
+ return ac_to_float(ctx, result);
+}
+
+/**
+ * Generate a fully general open coded buffer format fetch with all required
+ * fixups suitable for vertex fetch, using non-format buffer loads.
+ *
+ * Some combinations of argument values have special interpretations:
+ * - size = 8 bytes, format = fixed indicates PIPE_FORMAT_R11G11B10_FLOAT
+ * - size = 8 bytes, format != {float,fixed} indicates a 2_10_10_10 data format
+ *
+ * \param log_size log(size of channel in bytes)
+ * \param num_channels number of channels (1 to 4)
+ * \param format AC_FETCH_FORMAT_xxx value
+ * \param reverse whether XYZ channels are reversed
+ * \param known_aligned whether the source is known to be aligned to hardware's
+ * effective element size for loading the given format
+ * (note: this means dword alignment for 8_8_8_8, 16_16, etc.)
+ * \param rsrc buffer resource descriptor
+ * \return the resulting vector of floats or integers bitcast to <4 x i32>
+ */
+LLVMValueRef
+ac_build_opencoded_load_format(struct ac_llvm_context *ctx,
+ unsigned log_size,
+ unsigned num_channels,
+ unsigned format,
+ bool reverse,
+ bool known_aligned,
+ LLVMValueRef rsrc,
+ LLVMValueRef vindex,
+ LLVMValueRef voffset,
+ LLVMValueRef soffset,
+ bool glc,
+ bool slc,
+ bool can_speculate)
+{
+ LLVMValueRef tmp;
+ unsigned load_log_size = log_size;
+ unsigned load_num_channels = num_channels;
+ if (log_size == 3) {
+ load_log_size = 2;
+ if (format == AC_FETCH_FORMAT_FLOAT) {
+ load_num_channels = 2 * num_channels;
+ } else {
+ load_num_channels = 1; /* 10_11_11 or 2_10_10_10 */
+ }
+ }
+
+ int log_recombine = 0;
+ if (ctx->chip_class == SI && !known_aligned) {
+ /* Avoid alignment restrictions by loading one byte at a time. */
+ load_num_channels <<= load_log_size;
+ log_recombine = load_log_size;
+ load_log_size = 0;
+ } else if (load_num_channels == 2 || load_num_channels == 4) {
+ log_recombine = -util_logbase2(load_num_channels);
+ load_num_channels = 1;
+ load_log_size += -log_recombine;
+ }
+
+ assert(load_log_size >= 2 || HAVE_LLVM >= 0x0900);
+
+ LLVMValueRef loads[32]; /* up to 32 bytes */
+ for (unsigned i = 0; i < load_num_channels; ++i) {
+ tmp = LLVMBuildAdd(ctx->builder, soffset,
+ LLVMConstInt(ctx->i32, i << load_log_size, false), "");
+ if (HAVE_LLVM >= 0x0800) {
+ LLVMTypeRef channel_type = load_log_size == 0 ? ctx->i8 :
+ load_log_size == 1 ? ctx->i16 : ctx->i32;
+ unsigned num_channels = 1 << (MAX2(load_log_size, 2) - 2);
+ loads[i] = ac_build_llvm8_buffer_load_common(
+ ctx, rsrc, vindex, voffset, tmp,
+ num_channels, channel_type, glc, slc,
+ can_speculate, false, true);
+ } else {
+ tmp = LLVMBuildAdd(ctx->builder, voffset, tmp, "");
+ loads[i] = ac_build_buffer_load_common(
+ ctx, rsrc, vindex, tmp,
+ 1 << (load_log_size - 2), glc, slc, can_speculate, false);
+ }
+ if (load_log_size >= 2)
+ loads[i] = ac_to_integer(ctx, loads[i]);
+ }
+
+ if (log_recombine > 0) {
+ /* Recombine bytes if necessary (SI only) */
+ LLVMTypeRef dst_type = log_recombine == 2 ? ctx->i32 : ctx->i16;
+ LLVMValueRef accum;
+
+ for (unsigned src = 0, dst = 0; src < load_num_channels; ++dst) {
+ for (unsigned i = 0; i < (1 << log_recombine); ++i, ++src) {
+ tmp = LLVMBuildZExt(ctx->builder, loads[src], dst_type, "");
+ if (i == 0) {
+ accum = tmp;
+ } else {
+ tmp = LLVMBuildShl(ctx->builder, tmp,
+ LLVMConstInt(dst_type, 8 * i, false), "");
+ accum = LLVMBuildOr(ctx->builder, accum, tmp, "");
+ }
+ }
+ loads[dst] = accum;
+ }
+ } else if (log_recombine < 0) {
+ /* Split vectors of dwords */
+ if (load_log_size > 2) {
+ assert(load_num_channels == 1);
+ LLVMValueRef loaded = loads[0];
+ unsigned log_split = load_log_size - 2;
+ log_recombine += log_split;
+ load_num_channels = 1 << log_split;
+ load_log_size = 2;
+ for (unsigned i = 0; i < load_num_channels; ++i) {
+ tmp = LLVMConstInt(ctx->i32, i, false);
+ loads[i] = LLVMBuildExtractElement(ctx->builder, loaded, tmp, "");
+ }
+ }
+
+ /* Further split dwords and shorts if required */
+ if (log_recombine < 0) {
+ for (unsigned src = load_num_channels,
+ dst = load_num_channels << -log_recombine;
+ src > 0; --src) {
+ unsigned dst_bits = 1 << (3 + load_log_size + log_recombine);
+ LLVMTypeRef dst_type = LLVMIntTypeInContext(ctx->context, dst_bits);
+ LLVMValueRef loaded = loads[src - 1];
+ LLVMTypeRef loaded_type = LLVMTypeOf(loaded);
+ for (unsigned i = 1 << -log_recombine; i > 0; --i, --dst) {
+ tmp = LLVMConstInt(loaded_type, dst_bits * (i - 1), false);
+ tmp = LLVMBuildLShr(ctx->builder, loaded, tmp, "");
+ loads[dst - 1] = LLVMBuildTrunc(ctx->builder, tmp, dst_type, "");
+ }
+ }
+ }
+ }
+
+ if (log_size == 3) {
+ if (format == AC_FETCH_FORMAT_FLOAT) {
+ for (unsigned i = 0; i < num_channels; ++i) {
+ tmp = ac_build_gather_values(ctx, &loads[2 * i], 2);
+ loads[i] = LLVMBuildBitCast(ctx->builder, tmp, ctx->f64, "");
+ }
+ } else if (format == AC_FETCH_FORMAT_FIXED) {
+ /* 10_11_11_FLOAT */
+ LLVMValueRef data = loads[0];
+ LLVMValueRef i32_2047 = LLVMConstInt(ctx->i32, 2047, false);
+ LLVMValueRef r = LLVMBuildAnd(ctx->builder, data, i32_2047, "");
+ tmp = LLVMBuildLShr(ctx->builder, data, LLVMConstInt(ctx->i32, 11, false), "");
+ LLVMValueRef g = LLVMBuildAnd(ctx->builder, tmp, i32_2047, "");
+ LLVMValueRef b = LLVMBuildLShr(ctx->builder, data, LLVMConstInt(ctx->i32, 22, false), "");
+
+ loads[0] = ac_to_integer(ctx, ac_ufN_to_float(ctx, r, 5, 6));
+ loads[1] = ac_to_integer(ctx, ac_ufN_to_float(ctx, g, 5, 6));
+ loads[2] = ac_to_integer(ctx, ac_ufN_to_float(ctx, b, 5, 5));
+
+ num_channels = 3;
+ log_size = 2;
+ format = AC_FETCH_FORMAT_FLOAT;
+ } else {
+ /* 2_10_10_10 data formats */
+ LLVMValueRef data = loads[0];
+ LLVMTypeRef i10 = LLVMIntTypeInContext(ctx->context, 10);
+ LLVMTypeRef i2 = LLVMIntTypeInContext(ctx->context, 2);
+ loads[0] = LLVMBuildTrunc(ctx->builder, data, i10, "");
+ tmp = LLVMBuildLShr(ctx->builder, data, LLVMConstInt(ctx->i32, 10, false), "");
+ loads[1] = LLVMBuildTrunc(ctx->builder, tmp, i10, "");
+ tmp = LLVMBuildLShr(ctx->builder, data, LLVMConstInt(ctx->i32, 20, false), "");
+ loads[2] = LLVMBuildTrunc(ctx->builder, tmp, i10, "");
+ tmp = LLVMBuildLShr(ctx->builder, data, LLVMConstInt(ctx->i32, 30, false), "");
+ loads[3] = LLVMBuildTrunc(ctx->builder, tmp, i2, "");
+
+ num_channels = 4;
+ }
+ }
+
+ if (format == AC_FETCH_FORMAT_FLOAT) {
+ if (log_size != 2) {
+ for (unsigned chan = 0; chan < num_channels; ++chan) {
+ tmp = ac_to_float(ctx, loads[chan]);
+ if (log_size == 3)
+ tmp = LLVMBuildFPTrunc(ctx->builder, tmp, ctx->f32, "");
+ else if (log_size == 1)
+ tmp = LLVMBuildFPExt(ctx->builder, tmp, ctx->f32, "");
+ loads[chan] = ac_to_integer(ctx, tmp);
+ }
+ }
+ } else if (format == AC_FETCH_FORMAT_UINT) {
+ if (log_size != 2) {
+ for (unsigned chan = 0; chan < num_channels; ++chan)
+ loads[chan] = LLVMBuildZExt(ctx->builder, loads[chan], ctx->i32, "");
+ }
+ } else if (format == AC_FETCH_FORMAT_SINT) {
+ if (log_size != 2) {
+ for (unsigned chan = 0; chan < num_channels; ++chan)
+ loads[chan] = LLVMBuildSExt(ctx->builder, loads[chan], ctx->i32, "");
+ }
+ } else {
+ bool unsign = format == AC_FETCH_FORMAT_UNORM ||
+ format == AC_FETCH_FORMAT_USCALED ||
+ format == AC_FETCH_FORMAT_UINT;
+
+ for (unsigned chan = 0; chan < num_channels; ++chan) {
+ if (unsign) {
+ tmp = LLVMBuildUIToFP(ctx->builder, loads[chan], ctx->f32, "");
+ } else {
+ tmp = LLVMBuildSIToFP(ctx->builder, loads[chan], ctx->f32, "");
+ }
+
+ LLVMValueRef scale = NULL;
+ if (format == AC_FETCH_FORMAT_FIXED) {
+ assert(log_size == 2);
+ scale = LLVMConstReal(ctx->f32, 1.0 / 0x10000);
+ } else if (format == AC_FETCH_FORMAT_UNORM) {
+ unsigned bits = LLVMGetIntTypeWidth(LLVMTypeOf(loads[chan]));
+ scale = LLVMConstReal(ctx->f32, 1.0 / (((uint64_t)1 << bits) - 1));
+ } else if (format == AC_FETCH_FORMAT_SNORM) {
+ unsigned bits = LLVMGetIntTypeWidth(LLVMTypeOf(loads[chan]));
+ scale = LLVMConstReal(ctx->f32, 1.0 / (((uint64_t)1 << (bits - 1)) - 1));
+ }
+ if (scale)
+ tmp = LLVMBuildFMul(ctx->builder, tmp, scale, "");
+
+ if (format == AC_FETCH_FORMAT_SNORM) {
+ /* Clamp to [-1, 1] */
+ LLVMValueRef neg_one = LLVMConstReal(ctx->f32, -1.0);
+ LLVMValueRef clamp =
+ LLVMBuildFCmp(ctx->builder, LLVMRealULT, tmp, neg_one, "");
+ tmp = LLVMBuildSelect(ctx->builder, clamp, neg_one, tmp, "");
+ }
+
+ loads[chan] = ac_to_integer(ctx, tmp);
+ }
+ }
+
+ while (num_channels < 4) {
+ if (format == AC_FETCH_FORMAT_UINT || format == AC_FETCH_FORMAT_SINT) {
+ loads[num_channels] = num_channels == 3 ? ctx->i32_1 : ctx->i32_0;
+ } else {
+ loads[num_channels] = ac_to_integer(ctx, num_channels == 3 ? ctx->f32_1 : ctx->f32_0);
+ }
+ num_channels++;
+ }
+
+ if (reverse) {
+ tmp = loads[0];
+ loads[0] = loads[2];
+ loads[2] = tmp;
+ }
+
+ return ac_build_gather_values(ctx, loads, 4);
+}
+
static void
ac_build_llvm8_tbuffer_store(struct ac_llvm_context *ctx,
LLVMValueRef rsrc,
LLVMValueRef vdata,
LLVMValueRef vindex,
LLVMValueRef voffset,
LLVMValueRef soffset,
unsigned num_channels,
unsigned dfmt,
unsigned nfmt,
diff --git a/src/amd/common/ac_llvm_build.h b/src/amd/common/ac_llvm_build.h
index f4cee667153..71f903361db 100644
--- a/src/amd/common/ac_llvm_build.h
+++ b/src/amd/common/ac_llvm_build.h
@@ -350,20 +350,50 @@ ac_build_raw_tbuffer_load(struct ac_llvm_context *ctx,
LLVMValueRef voffset,
LLVMValueRef soffset,
LLVMValueRef immoffset,
unsigned num_channels,
unsigned dfmt,
unsigned nfmt,
bool glc,
bool slc,
bool can_speculate);
+/* For ac_build_fetch_format.
+ *
+ * Note: FLOAT must be 0 (used for convenience of encoding in radeonsi).
+ */
+enum {
+ AC_FETCH_FORMAT_FLOAT = 0,
+ AC_FETCH_FORMAT_FIXED,
+ AC_FETCH_FORMAT_UNORM,
+ AC_FETCH_FORMAT_SNORM,
+ AC_FETCH_FORMAT_USCALED,
+ AC_FETCH_FORMAT_SSCALED,
+ AC_FETCH_FORMAT_UINT,
+ AC_FETCH_FORMAT_SINT,
+};
+
+LLVMValueRef
+ac_build_opencoded_load_format(struct ac_llvm_context *ctx,
+ unsigned log_size,
+ unsigned num_channels,
+ unsigned format,
+ bool reverse,
+ bool known_aligned,
+ LLVMValueRef rsrc,
+ LLVMValueRef vindex,
+ LLVMValueRef voffset,
+ LLVMValueRef soffset,
+ bool glc,
+ bool slc,
+ bool can_speculate);
+
void
ac_build_tbuffer_store_short(struct ac_llvm_context *ctx,
LLVMValueRef rsrc,
LLVMValueRef vdata,
LLVMValueRef voffset,
LLVMValueRef soffset,
bool glc,
bool writeonly_memory);
void
--
2.20.1
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