src/gallium/drivers/llvmpipe/lp_bld_logic.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2009 VMware, Inc.
   4  * All Rights Reserved.
   5  *
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   7  * copy of this software and associated documentation files (the
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  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
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  26  **************************************************************************/
  27
  28 /**
  29  * @file
  30  * Helper functions for logical operations.
  31  *
  32  * @author Jose Fonseca <jfonseca@vmware.com>
  33  */
  34
  35
  36 #include "util/u_cpu_detect.h"
  37 #include "util/u_debug.h"
  38
  39 #include "lp_bld_type.h"
  40 #include "lp_bld_const.h"
  41 #include "lp_bld_intr.h"
  42 #include "lp_bld_logic.h"
  43
  44
  45 /**
  46  * Build code to compare two values 'a' and 'b' of 'type' using the given func.
  47  * \param func  one of PIPE_FUNC_x
  48  */
  49 LLVMValueRef
  50 lp_build_compare(LLVMBuilderRef builder,
  51                  const struct lp_type type,
  52                  unsigned func,
  53                  LLVMValueRef a,
  54                  LLVMValueRef b)
  55 {
  56    LLVMTypeRef vec_type = lp_build_vec_type(type);
  57    LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
  58    LLVMValueRef zeros = LLVMConstNull(int_vec_type);
  59    LLVMValueRef ones = LLVMConstAllOnes(int_vec_type);
  60    LLVMValueRef cond;
  61    LLVMValueRef res;
  62    unsigned i;
  63
  64    assert(func >= PIPE_FUNC_NEVER);
  65    assert(func <= PIPE_FUNC_ALWAYS);
  66
  67    if(func == PIPE_FUNC_NEVER)
  68       return zeros;
  69    if(func == PIPE_FUNC_ALWAYS)
  70       return ones;
  71
  72    /* TODO: optimize the constant case */
  73
  74    /* XXX: It is not clear if we should use the ordered or unordered operators */
  75
  76 #if defined(PIPE_ARCH_X86) || defined(PIPE_ARCH_X86_64)
  77    if(type.width * type.length == 128) {
  78       if(type.floating && util_cpu_caps.has_sse) {
  79          /* float[4] comparison */
  80          LLVMValueRef args[3];
  81          unsigned cc;
  82          boolean swap;
  83
  84          swap = FALSE;
  85          switch(func) {
  86          case PIPE_FUNC_EQUAL:
  87             cc = 0;
  88             break;
  89          case PIPE_FUNC_NOTEQUAL:
  90             cc = 4;
  91             break;
  92          case PIPE_FUNC_LESS:
  93             cc = 1;
  94             break;
  95          case PIPE_FUNC_LEQUAL:
  96             cc = 2;
  97             break;
  98          case PIPE_FUNC_GREATER:
  99             cc = 1;
 100             swap = TRUE;
 101             break;
 102          case PIPE_FUNC_GEQUAL:
 103             cc = 2;
 104             swap = TRUE;
 105             break;
 106          default:
 107             assert(0);
 108             return lp_build_undef(type);
 109          }
 110
 111          if(swap) {
 112             args[0] = b;
 113             args[1] = a;
 114          }
 115          else {
 116             args[0] = a;
 117             args[1] = b;
 118          }
 119
 120          args[2] = LLVMConstInt(LLVMInt8Type(), cc, 0);
 121          res = lp_build_intrinsic(builder,
 122                                   "llvm.x86.sse.cmp.ps",
 123                                   vec_type,
 124                                   args, 3);
 125          res = LLVMBuildBitCast(builder, res, int_vec_type, "");
 126          return res;
 127       }
 128       else if(util_cpu_caps.has_sse2) {
 129          /* int[4] comparison */
 130          static const struct {
 131             unsigned swap:1;
 132             unsigned eq:1;
 133             unsigned gt:1;
 134             unsigned not:1;
 135          } table[] = {
 136             {0, 0, 0, 1}, /* PIPE_FUNC_NEVER */
 137             {1, 0, 1, 0}, /* PIPE_FUNC_LESS */
 138             {0, 1, 0, 0}, /* PIPE_FUNC_EQUAL */
 139             {0, 0, 1, 1}, /* PIPE_FUNC_LEQUAL */
 140             {0, 0, 1, 0}, /* PIPE_FUNC_GREATER */
 141             {0, 1, 0, 1}, /* PIPE_FUNC_NOTEQUAL */
 142             {1, 0, 1, 1}, /* PIPE_FUNC_GEQUAL */
 143             {0, 0, 0, 0}  /* PIPE_FUNC_ALWAYS */
 144          };
 145          const char *pcmpeq;
 146          const char *pcmpgt;
 147          LLVMValueRef args[2];
 148          LLVMValueRef res;
 149
 150          switch (type.width) {
 151          case 8:
 152             pcmpeq = "llvm.x86.sse2.pcmpeq.b";
 153             pcmpgt = "llvm.x86.sse2.pcmpgt.b";
 154             break;
 155          case 16:
 156             pcmpeq = "llvm.x86.sse2.pcmpeq.w";
 157             pcmpgt = "llvm.x86.sse2.pcmpgt.w";
 158             break;
 159          case 32:
 160             pcmpeq = "llvm.x86.sse2.pcmpeq.d";
 161             pcmpgt = "llvm.x86.sse2.pcmpgt.d";
 162             break;
 163          default:
 164             assert(0);
 165             return lp_build_undef(type);
 166          }
 167
 168          /* There are no signed byte and unsigned word/dword comparison
 169           * instructions. So flip the sign bit so that the results match.
 170           */
 171          if(table[func].gt &&
 172             ((type.width == 8 && type.sign) ||
 173              (type.width != 8 && !type.sign))) {
 174             LLVMValueRef msb = lp_build_int_const_scalar(type, (unsigned long long)1 << (type.width - 1));
 175             a = LLVMBuildXor(builder, a, msb, "");
 176             b = LLVMBuildXor(builder, b, msb, "");
 177          }
 178
 179          if(table[func].swap) {
 180             args[0] = b;
 181             args[1] = a;
 182          }
 183          else {
 184             args[0] = a;
 185             args[1] = b;
 186          }
 187
 188          if(table[func].eq)
 189             res = lp_build_intrinsic(builder, pcmpeq, vec_type, args, 2);
 190          else if (table[func].gt)
 191             res = lp_build_intrinsic(builder, pcmpgt, vec_type, args, 2);
 192          else
 193             res = LLVMConstNull(vec_type);
 194
 195          if(table[func].not)
 196             res = LLVMBuildNot(builder, res, "");
 197
 198          return res;
 199       }
 200    }
 201 #endif
 202
 203    if(type.floating) {
 204       LLVMRealPredicate op;
 205       switch(func) {
 206       case PIPE_FUNC_NEVER:
 207          op = LLVMRealPredicateFalse;
 208          break;
 209       case PIPE_FUNC_ALWAYS:
 210          op = LLVMRealPredicateTrue;
 211          break;
 212       case PIPE_FUNC_EQUAL:
 213          op = LLVMRealUEQ;
 214          break;
 215       case PIPE_FUNC_NOTEQUAL:
 216          op = LLVMRealUNE;
 217          break;
 218       case PIPE_FUNC_LESS:
 219          op = LLVMRealULT;
 220          break;
 221       case PIPE_FUNC_LEQUAL:
 222          op = LLVMRealULE;
 223          break;
 224       case PIPE_FUNC_GREATER:
 225          op = LLVMRealUGT;
 226          break;
 227       case PIPE_FUNC_GEQUAL:
 228          op = LLVMRealUGE;
 229          break;
 230       default:
 231          assert(0);
 232          return lp_build_undef(type);
 233       }
 234
 235 #if 0
 236       /* XXX: Although valid IR, no LLVM target currently support this */
 237       cond = LLVMBuildFCmp(builder, op, a, b, "");
 238       res = LLVMBuildSelect(builder, cond, ones, zeros, "");
 239 #else
 240       debug_printf("%s: warning: using slow element-wise vector comparison\n",
 241                    __FUNCTION__);
 242       res = LLVMGetUndef(int_vec_type);
 243       for(i = 0; i < type.length; ++i) {
 244          LLVMValueRef index = LLVMConstInt(LLVMInt32Type(), i, 0);
 245          cond = LLVMBuildFCmp(builder, op,
 246                               LLVMBuildExtractElement(builder, a, index, ""),
 247                               LLVMBuildExtractElement(builder, b, index, ""),
 248                               "");
 249          cond = LLVMBuildSelect(builder, cond,
 250                                 LLVMConstExtractElement(ones, index),
 251                                 LLVMConstExtractElement(zeros, index),
 252                                 "");
 253          res = LLVMBuildInsertElement(builder, res, cond, index, "");
 254       }
 255 #endif
 256    }
 257    else {
 258       LLVMIntPredicate op;
 259       switch(func) {
 260       case PIPE_FUNC_EQUAL:
 261          op = LLVMIntEQ;
 262          break;
 263       case PIPE_FUNC_NOTEQUAL:
 264          op = LLVMIntNE;
 265          break;
 266       case PIPE_FUNC_LESS:
 267          op = type.sign ? LLVMIntSLT : LLVMIntULT;
 268          break;
 269       case PIPE_FUNC_LEQUAL:
 270          op = type.sign ? LLVMIntSLE : LLVMIntULE;
 271          break;
 272       case PIPE_FUNC_GREATER:
 273          op = type.sign ? LLVMIntSGT : LLVMIntUGT;
 274          break;
 275       case PIPE_FUNC_GEQUAL:
 276          op = type.sign ? LLVMIntSGE : LLVMIntUGE;
 277          break;
 278       default:
 279          assert(0);
 280          return lp_build_undef(type);
 281       }
 282
 283 #if 0
 284       /* XXX: Although valid IR, no LLVM target currently support this */
 285       cond = LLVMBuildICmp(builder, op, a, b, "");
 286       res = LLVMBuildSelect(builder, cond, ones, zeros, "");
 287 #else
 288       debug_printf("%s: warning: using slow element-wise int vector comparison\n",
 289                    __FUNCTION__);
 290       res = LLVMGetUndef(int_vec_type);
 291       for(i = 0; i < type.length; ++i) {
 292          LLVMValueRef index = LLVMConstInt(LLVMInt32Type(), i, 0);
 293          cond = LLVMBuildICmp(builder, op,
 294                               LLVMBuildExtractElement(builder, a, index, ""),
 295                               LLVMBuildExtractElement(builder, b, index, ""),
 296                               "");
 297          cond = LLVMBuildSelect(builder, cond,
 298                                 LLVMConstExtractElement(ones, index),
 299                                 LLVMConstExtractElement(zeros, index),
 300                                 "");
 301          res = LLVMBuildInsertElement(builder, res, cond, index, "");
 302       }
 303 #endif
 304    }
 305
 306    return res;
 307 }
 308
 309
 310
 311 /**
 312  * Build code to compare two values 'a' and 'b' using the given func.
 313  * \param func  one of PIPE_FUNC_x
 314  */
 315 LLVMValueRef
 316 lp_build_cmp(struct lp_build_context *bld,
 317              unsigned func,
 318              LLVMValueRef a,
 319              LLVMValueRef b)
 320 {
 321    return lp_build_compare(bld->builder, bld->type, func, a, b);
 322 }
 323
 324
 325 LLVMValueRef
 326 lp_build_select(struct lp_build_context *bld,
 327                 LLVMValueRef mask,
 328                 LLVMValueRef a,
 329                 LLVMValueRef b)
 330 {
 331    struct lp_type type = bld->type;
 332    LLVMValueRef res;
 333
 334    if(a == b)
 335       return a;
 336
 337    if(type.floating) {
 338       LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
 339       a = LLVMBuildBitCast(bld->builder, a, int_vec_type, "");
 340       b = LLVMBuildBitCast(bld->builder, b, int_vec_type, "");
 341    }
 342
 343    a = LLVMBuildAnd(bld->builder, a, mask, "");
 344
 345    /* This often gets translated to PANDN, but sometimes the NOT is
 346     * pre-computed and stored in another constant. The best strategy depends
 347     * on available registers, so it is not a big deal -- hopefully LLVM does
 348     * the right decision attending the rest of the program.
 349     */
 350    b = LLVMBuildAnd(bld->builder, b, LLVMBuildNot(bld->builder, mask, ""), "");
 351
 352    res = LLVMBuildOr(bld->builder, a, b, "");
 353
 354    if(type.floating) {
 355       LLVMTypeRef vec_type = lp_build_vec_type(type);
 356       res = LLVMBuildBitCast(bld->builder, res, vec_type, "");
 357    }
 358
 359    return res;
 360 }
 361
 362
 363 LLVMValueRef
 364 lp_build_select_aos(struct lp_build_context *bld,
 365                     LLVMValueRef a,
 366                     LLVMValueRef b,
 367                     const boolean cond[4])
 368 {
 369    const struct lp_type type = bld->type;
 370    const unsigned n = type.length;
 371    unsigned i, j;
 372
 373    if(a == b)
 374       return a;
 375    if(cond[0] && cond[1] && cond[2] && cond[3])
 376       return a;
 377    if(!cond[0] && !cond[1] && !cond[2] && !cond[3])
 378       return b;
 379    if(a == bld->undef || b == bld->undef)
 380       return bld->undef;
 381
 382    /*
 383     * There are three major ways of accomplishing this:
 384     * - with a shuffle,
 385     * - with a select,
 386     * - or with a bit mask.
 387     *
 388     * Select isn't supported for vector types yet.
 389     * The flip between these is empirical and might need to be.
 390     */
 391    if (n <= 4) {
 392       /*
 393        * Shuffle.
 394        */
 395       LLVMTypeRef elem_type = LLVMInt32Type();
 396       LLVMValueRef shuffles[LP_MAX_VECTOR_LENGTH];
 397
 398       for(j = 0; j < n; j += 4)
 399          for(i = 0; i < 4; ++i)
 400             shuffles[j + i] = LLVMConstInt(elem_type, (cond[i] ? 0 : n) + j + i, 0);
 401
 402       return LLVMBuildShuffleVector(bld->builder, a, b, LLVMConstVector(shuffles, n), "");
 403    }
 404    else {
 405 #if 0
 406       /* XXX: Unfortunately select of vectors do not work */
 407       /* Use a select */
 408       LLVMTypeRef elem_type = LLVMInt1Type();
 409       LLVMValueRef cond[LP_MAX_VECTOR_LENGTH];
 410
 411       for(j = 0; j < n; j += 4)
 412          for(i = 0; i < 4; ++i)
 413             cond[j + i] = LLVMConstInt(elem_type, cond[i] ? 1 : 0, 0);
 414
 415       return LLVMBuildSelect(bld->builder, LLVMConstVector(cond, n), a, b, "");
 416 #else
 417       LLVMValueRef mask = lp_build_const_mask_aos(type, cond);
 418       return lp_build_select(bld, mask, a, b);
 419 #endif
 420    }
 421 }