amd/common: add ac_build_opencoded_fetch_format
authorNicolai Hähnle <nicolai.haehnle@amd.com>
Fri, 29 Mar 2019 22:03:51 +0000 (23:03 +0100)
committerNicolai Hähnle <nicolai.haehnle@amd.com>
Mon, 13 May 2019 15:07:23 +0000 (17:07 +0200)
Implement software emulation of buffer_load_format for all types required
by vertex buffer fetches.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
src/amd/common/ac_llvm_build.c
src/amd/common/ac_llvm_build.h

index 22b771db7749ec792b216f0e14eab13837b39815..f1ed68d5df36266f17ad516499834123e35cd68a 100644 (file)
@@ -1673,6 +1673,319 @@ ac_build_tbuffer_load_byte(struct ac_llvm_context *ctx,
 
        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;
+
+               for (unsigned src = 0, dst = 0; src < load_num_channels; ++dst) {
+                       LLVMValueRef accum = NULL;
+                       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,
index 98f856106d67ec0615f964e0479160bd356e8e9c..c284526727ae685ba1bf69a0b531ff5c0ebd36f4 100644 (file)
@@ -357,6 +357,36 @@ ac_build_raw_tbuffer_load(struct ac_llvm_context *ctx,
                          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,