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/**************************************************************************

 *

 * Copyright 2009 VMware, Inc.

 * All Rights Reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sub license, and/or sell copies of the Software, and to

 * permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice (including the

 * next paragraph) shall be included in all copies or substantial portions

 * of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.

 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR

 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,

 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 *

 **************************************************************************/

/**

 * @file

 * Helper functions for type conversions.

 *

 * We want to use the fastest type for a given computation whenever feasible.

 * The other side of this is that we need to be able convert between several

 * types accurately and efficiently.

 *

 * Conversion between types of different bit width is quite complex since a

 *

 * To remember there are a few invariants in type conversions:

 *

 * - register width must remain constant:

 *

 *     src_type.width * src_type.length == dst_type.width * dst_type.length

 *

 * - total number of elements must remain constant:

 *

 *     src_type.length * num_srcs == dst_type.length * num_dsts

 *

 * It is not always possible to do the conversion both accurately and

 * efficiently, usually due to lack of adequate machine instructions. In these

 * cases it is important not to cut shortcuts here and sacrifice accuracy, as

 * there this functions can be used anywhere. In the future we might have a

 * precision parameter which can gauge the accuracy vs efficiency compromise,

 * but for now if the data conversion between two stages happens to be the

 * bottleneck, then most likely should just avoid converting at all and run

 * both stages with the same type.

 *

 * Make sure to run lp_test_conv unit test after any change to this file.

 *

 * @author Jose Fonseca 

 */

#include "util/u_debug.h"

#include "util/u_math.h"

#include "util/u_half.h"

#include "util/u_cpu_detect.h"

#include "lp_bld_type.h"

#include "lp_bld_const.h"

#include "lp_bld_arit.h"

#include "lp_bld_bitarit.h"

#include "lp_bld_pack.h"

#include "lp_bld_conv.h"

#include "lp_bld_logic.h"

#include "lp_bld_intr.h"

#include "lp_bld_printf.h"

#include "lp_bld_format.h"

/**

 * Converts int16 half-float to float32

 * Note this can be performed in 1 instruction if vcvtph2ps exists (f16c/cvt16)

 * [llvm.x86.vcvtph2ps / _mm_cvtph_ps]

 *

 * @param src           value to convert

 *

 */

LLVMValueRef

lp_build_half_to_float(struct gallivm_state *gallivm,

                       LLVMValueRef src)

{

   LLVMBuilderRef builder = gallivm->builder;

   LLVMTypeRef src_type = LLVMTypeOf(src);

   unsigned src_length = LLVMGetTypeKind(src_type) == LLVMVectorTypeKind ?

                            LLVMGetVectorSize(src_type) : 1;

   struct lp_type f32_type = lp_type_float_vec(32, 32 * src_length);

   struct lp_type i32_type = lp_type_int_vec(32, 32 * src_length);

   LLVMTypeRef int_vec_type = lp_build_vec_type(gallivm, i32_type);

   LLVMValueRef h;

   if (util_cpu_caps.has_f16c && HAVE_LLVM >= 0x0301 &&

       (src_length == 4 || src_length == 8)) {

      const char *intrinsic = NULL;

      if (src_length == 4) {

         src = lp_build_pad_vector(gallivm, src, 8);

         intrinsic = "llvm.x86.vcvtph2ps.128";

      }

      else {

         intrinsic = "llvm.x86.vcvtph2ps.256";

      }

      return lp_build_intrinsic_unary(builder, intrinsic,

                                      lp_build_vec_type(gallivm, f32_type), src);

   }

   /* Convert int16 vector to int32 vector by zero ext (might generate bad code) */

   h = LLVMBuildZExt(builder, src, int_vec_type, "");

   return lp_build_smallfloat_to_float(gallivm, f32_type, h, 10, 5, 0, true);

}

/**

 * Converts float32 to int16 half-float

 * Note this can be performed in 1 instruction if vcvtps2ph exists (f16c/cvt16)

 * [llvm.x86.vcvtps2ph / _mm_cvtps_ph]

 *

 * @param src           value to convert

 *

 * Convert float32 to half floats, preserving Infs and NaNs,

 * with rounding towards zero (trunc).

 */

LLVMValueRef

lp_build_float_to_half(struct gallivm_state *gallivm,

                       LLVMValueRef src)

{

   LLVMBuilderRef builder = gallivm->builder;

   LLVMTypeRef f32_vec_type = LLVMTypeOf(src);

   unsigned length = LLVMGetTypeKind(f32_vec_type) == LLVMVectorTypeKind

                   ? LLVMGetVectorSize(f32_vec_type) : 1;

   struct lp_type i32_type = lp_type_int_vec(32, 32 * length);

   struct lp_type i16_type = lp_type_int_vec(16, 16 * length);

   LLVMValueRef result;

   if (util_cpu_caps.has_f16c && HAVE_LLVM >= 0x0301 &&

       (length == 4 || length == 8)) {

      struct lp_type i168_type = lp_type_int_vec(16, 16 * 8);

      unsigned mode = 3; /* same as LP_BUILD_ROUND_TRUNCATE */

      LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);

      const char *intrinsic = NULL;

      if (length == 4) {

         intrinsic = "llvm.x86.vcvtps2ph.128";

      }

      else {

         intrinsic = "llvm.x86.vcvtps2ph.256";

      }

      result = lp_build_intrinsic_binary(builder, intrinsic,

                                         lp_build_vec_type(gallivm, i168_type),

                                         src, LLVMConstInt(i32t, mode, 0));

      if (length == 4) {

         result = lp_build_extract_range(gallivm, result, 0, 4);

      }

   }

   else {

      result = lp_build_float_to_smallfloat(gallivm, i32_type, src, 10, 5, 0, true);

      /* Convert int32 vector to int16 vector by trunc (might generate bad code) */

      result = LLVMBuildTrunc(builder, result, lp_build_vec_type(gallivm, i16_type), "");

   }

   /*

    * Debugging code.

    */

   if (0) {

     LLVMTypeRef i32t = LLVMInt32TypeInContext(gallivm->context);

     LLVMTypeRef i16t = LLVMInt16TypeInContext(gallivm->context);

     LLVMTypeRef f32t = LLVMFloatTypeInContext(gallivm->context);

     LLVMValueRef ref_result = LLVMGetUndef(LLVMVectorType(i16t, length));

     unsigned i;

     LLVMTypeRef func_type = LLVMFunctionType(i16t, &f32t, 1, 0);

     LLVMValueRef func = lp_build_const_int_pointer(gallivm, func_to_pointer((func_pointer)util_float_to_half));

     func = LLVMBuildBitCast(builder, func, LLVMPointerType(func_type, 0), "util_float_to_half");

     for (i = 0; i < length; ++i) {

        LLVMValueRef index = LLVMConstInt(i32t, i, 0);

        LLVMValueRef f32 = LLVMBuildExtractElement(builder, src, index, "");

#if 0

        /* XXX: not really supported by backends */

        LLVMValueRef f16 = lp_build_intrinsic_unary(builder, "llvm.convert.to.fp16", i16t, f32);

#else

        LLVMValueRef f16 = LLVMBuildCall(builder, func, &f32, 1, "");

#endif

        ref_result = LLVMBuildInsertElement(builder, ref_result, f16, index, "");

     }

     lp_build_print_value(gallivm, "src  = ", src);

     lp_build_print_value(gallivm, "llvm = ", result);

     lp_build_print_value(gallivm, "util = ", ref_result);

     lp_build_printf(gallivm, "\n");

  }

   return result;

}

/**

 * Special case for converting clamped IEEE-754 floats to unsigned norms.

 *

 * The mathematical voodoo below may seem excessive but it is actually

 * paramount we do it this way for several reasons. First, there is no single

 * precision FP to unsigned integer conversion Intel SSE instruction. Second,

 * secondly, even if there was, since the FP's mantissa takes only a fraction

 * of register bits the typically scale and cast approach would require double

 * precision for accurate results, and therefore half the throughput

 *

 * Although the result values can be scaled to an arbitrary bit width specified

 * by dst_width, the actual result type will have the same width.

 *

 * Ex: src = { float, float, float, float }

 * return { i32, i32, i32, i32 } where each value is in [0, 2^dst_width-1].

 */

LLVMValueRef

lp_build_clamped_float_to_unsigned_norm(struct gallivm_state *gallivm,

                                        struct lp_type src_type,

                                        unsigned dst_width,

                                        LLVMValueRef src)

{

   LLVMBuilderRef builder = gallivm->builder;

   LLVMTypeRef int_vec_type = lp_build_int_vec_type(gallivm, src_type);

   LLVMValueRef res;

   unsigned mantissa;

   assert(src_type.floating);

   assert(dst_width <= src_type.width);

   src_type.sign = FALSE;

   mantissa = lp_mantissa(src_type);

   if (dst_width <= mantissa) {

      /*

       * Apply magic coefficients that will make the desired result to appear

       * in the lowest significant bits of the mantissa, with correct rounding.

       *

       * This only works if the destination width fits in the mantissa.

       */

      unsigned long long ubound;

      unsigned long long mask;

      double scale;

      double bias;

      ubound = (1ULL << dst_width);

      mask = ubound - 1;

      scale = (double)mask/ubound;

      bias = (double)(1ULL << (mantissa - dst_width));

      res = LLVMBuildFMul(builder, src, lp_build_const_vec(gallivm, src_type, scale), "");

      res = LLVMBuildFAdd(builder, res, lp_build_const_vec(gallivm, src_type, bias), "");

      res = LLVMBuildBitCast(builder, res, int_vec_type, "");

      res = LLVMBuildAnd(builder, res,

                         lp_build_const_int_vec(gallivm, src_type, mask), "");

   }

   else if (dst_width == (mantissa + 1)) {

      /*

       * The destination width matches exactly what can be represented in

       * floating point (i.e., mantissa + 1 bits). So do a straight

       * multiplication followed by casting. No further rounding is necessary.

       */

      double scale;

      scale = (double)((1ULL << dst_width) - 1);

      res = LLVMBuildFMul(builder, src,

                          lp_build_const_vec(gallivm, src_type, scale), "");

      res = LLVMBuildFPToSI(builder, res, int_vec_type, "");

   }

   else {

      /*

       * The destination exceeds what can be represented in the floating point.

       * So multiply by the largest power two we get away with, and when

       * subtract the most significant bit to rescale to normalized values.

       *

       * The largest power of two factor we can get away is

       * (1 << (src_type.width - 1)), because we need to use signed . In theory it

       * should be (1 << (src_type.width - 2)), but IEEE 754 rules states

       * INT_MIN should be returned in FPToSI, which is the correct result for

       * values near 1.0!

       *

       * This means we get (src_type.width - 1) correct bits for values near 0.0,

       * and (mantissa + 1) correct bits for values near 1.0. Equally or more

       * important, we also get exact results for 0.0 and 1.0.

       */

      unsigned n = MIN2(src_type.width - 1, dst_width);

      double scale = (double)(1ULL << n);

      unsigned lshift = dst_width - n;

      unsigned rshift = n;

      LLVMValueRef lshifted;

      LLVMValueRef rshifted;

      res = LLVMBuildFMul(builder, src,

                          lp_build_const_vec(gallivm, src_type, scale), "");

      res = LLVMBuildFPToSI(builder, res, int_vec_type, "");

      /*

       * Align the most significant bit to its final place.

       *

       * This will cause 1.0 to overflow to 0, but the later adjustment will

       * get it right.

       */

      if (lshift) {

         lshifted = LLVMBuildShl(builder, res,

                                 lp_build_const_int_vec(gallivm, src_type,

                                                        lshift), "");

      } else {

         lshifted = res;

      }

      /*

       * Align the most significant bit to the right.

       */

      rshifted =  LLVMBuildLShr(builder, res,

                                lp_build_const_int_vec(gallivm, src_type, rshift),

                                "");

      /*

       * Subtract the MSB to the LSB, therefore re-scaling from

       * (1 << dst_width) to ((1 << dst_width) - 1).

       */

      res = LLVMBuildSub(builder, lshifted, rshifted, "");

   }

   return res;

}

/**

 * Inverse of lp_build_clamped_float_to_unsigned_norm above.

 * Ex: src = { i32, i32, i32, i32 } with values in range [0, 2^src_width-1]

 * return {float, float, float, float} with values in range [0, 1].

 */

LLVMValueRef

lp_build_unsigned_norm_to_float(struct gallivm_state *gallivm,

                                unsigned src_width,

                                struct lp_type dst_type,

                                LLVMValueRef src)

{

   LLVMBuilderRef builder = gallivm->builder;

   LLVMTypeRef vec_type = lp_build_vec_type(gallivm, dst_type);

   LLVMTypeRef int_vec_type = lp_build_int_vec_type(gallivm, dst_type);

   LLVMValueRef bias_;

   LLVMValueRef res;

   unsigned mantissa;

   unsigned n;

   unsigned long long ubound;

   unsigned long long mask;

   double scale;

   double bias;

   assert(dst_type.floating);

   mantissa = lp_mantissa(dst_type);

   if (src_width <= (mantissa + 1)) {

      /*

       * The source width matches fits what can be represented in floating

       * point (i.e., mantissa + 1 bits). So do a straight multiplication

       * followed by casting. No further rounding is necessary.

       */

      scale = 1.0/(double)((1ULL << src_width) - 1);

      res = LLVMBuildSIToFP(builder, src, vec_type, "");

      res = LLVMBuildFMul(builder, res,

                          lp_build_const_vec(gallivm, dst_type, scale), "");

      return res;

   }

   else {

      /*

       * The source width exceeds what can be represented in floating

       * point. So truncate the incoming values.

       */

      n = MIN2(mantissa, src_width);

      ubound = ((unsigned long long)1 << n);

      mask = ubound - 1;

      scale = (double)ubound/mask;

      bias = (double)((unsigned long long)1 << (mantissa - n));

      res = src;

      if (src_width > mantissa) {

         int shift = src_width - mantissa;

         res = LLVMBuildLShr(builder, res,

                             lp_build_const_int_vec(gallivm, dst_type, shift), "");

      }

      bias_ = lp_build_const_vec(gallivm, dst_type, bias);

      res = LLVMBuildOr(builder,

                        res,

                        LLVMBuildBitCast(builder, bias_, int_vec_type, ""), "");

      res = LLVMBuildBitCast(builder, res, vec_type, "");

      res = LLVMBuildFSub(builder, res, bias_, "");

      res = LLVMBuildFMul(builder, res, lp_build_const_vec(gallivm, dst_type, scale), "");

   }

   return res;

}

/**

 * Pick a suitable num_dsts for lp_build_conv to ensure optimal cases are used.

 *

 * Returns the number of dsts created from src

 */

int lp_build_conv_auto(struct gallivm_state *gallivm,

                       struct lp_type src_type,

                       struct lp_type* dst_type,

                       const LLVMValueRef *src,

                       unsigned num_srcs,

                       LLVMValueRef *dst)

{

   int i;

   int num_dsts = num_srcs;

   if (src_type.floating == dst_type->floating &&

       src_type.width == dst_type->width &&

       src_type.length == dst_type->length &&

       src_type.fixed == dst_type->fixed &&

       src_type.norm == dst_type->norm &&

       src_type.sign == dst_type->sign)

      return num_dsts;

   /* Special case 4x4f -> 1x16ub or 2x8f -> 1x16ub

    */

   if (src_type.floating == 1 &&

       src_type.fixed    == 0 &&

       src_type.sign     == 1 &&

       src_type.norm     == 0 &&

       src_type.width    == 32 &&

       dst_type->floating == 0 &&

       dst_type->fixed    == 0 &&

       dst_type->sign     == 0 &&

       dst_type->norm     == 1 &&

       dst_type->width    == 8)

   {

      /* Special case 4x4f --> 1x16ub */

      if (src_type.length == 4 &&

          util_cpu_caps.has_sse2)

      {

         num_dsts = (num_srcs + 3) / 4;

         dst_type->length = num_srcs * 4 >= 16 ? 16 : num_srcs * 4;

         lp_build_conv(gallivm, src_type, *dst_type, src, num_srcs, dst, num_dsts);

         return num_dsts;

      }

      /* Special case 2x8f --> 1x16ub */

      if (src_type.length == 8 &&

          util_cpu_caps.has_avx)

      {

         num_dsts = (num_srcs + 1) / 2;

         dst_type->length = num_srcs * 8 >= 16 ? 16 : num_srcs * 8;

         lp_build_conv(gallivm, src_type, *dst_type, src, num_srcs, dst, num_dsts);

         return num_dsts;

      }

   }

   /* lp_build_resize does not support M:N */

   if (src_type.width == dst_type->width) {

      lp_build_conv(gallivm, src_type, *dst_type, src, num_srcs, dst, num_dsts);

   } else {

      for (i = 0; i < num_srcs; ++i) {

         lp_build_conv(gallivm, src_type, *dst_type, &src[i], 1, &dst[i], 1);

      }

   }

   return num_dsts;

}

/**

 * Generic type conversion.

 *

 * TODO: Take a precision argument, or even better, add a new precision member

 * to the lp_type union.

 */

void

lp_build_conv(struct gallivm_state *gallivm,

              struct lp_type src_type,

              struct lp_type dst_type,

              const LLVMValueRef *src, unsigned num_srcs,

              LLVMValueRef *dst, unsigned num_dsts)

{

   LLVMBuilderRef builder = gallivm->builder;

   struct lp_type tmp_type;

   LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH];

   unsigned num_tmps;

   unsigned i;

   /* We must not loose or gain channels. Only precision */

   assert(src_type.length * num_srcs == dst_type.length * num_dsts);

   assert(src_type.length <= LP_MAX_VECTOR_LENGTH);

   assert(dst_type.length <= LP_MAX_VECTOR_LENGTH);

   assert(num_srcs <= LP_MAX_VECTOR_LENGTH);

   assert(num_dsts <= LP_MAX_VECTOR_LENGTH);

   tmp_type = src_type;

   for(i = 0; i < num_srcs; ++i) {

      assert(lp_check_value(src_type, src[i]));

      tmp[i] = src[i];

   }

   num_tmps = num_srcs;

   /* Special case 4x4f --> 1x16ub, 2x4f -> 1x8ub, 1x4f -> 1x4ub

    */

   if (src_type.floating == 1 &&

       src_type.fixed    == 0 &&

       src_type.sign     == 1 &&

       src_type.norm     == 0 &&

       src_type.width    == 32 &&

       src_type.length   == 4 &&

       dst_type.floating == 0 &&

       dst_type.fixed    == 0 &&

       dst_type.sign     == 0 &&

       dst_type.norm     == 1 &&

       dst_type.width    == 8 &&

       ((dst_type.length == 16 && 4 * num_dsts == num_srcs) ||

        (num_dsts == 1 && dst_type.length * num_srcs == 16 && num_srcs != 3)) &&

       util_cpu_caps.has_sse2)

   {

      struct lp_build_context bld;

      struct lp_type int16_type, int32_type;

      struct lp_type dst_type_ext = dst_type;

      LLVMValueRef const_255f;

      unsigned i, j;

      lp_build_context_init(&bld, gallivm, src_type);

      dst_type_ext.length = 16;

      int16_type = int32_type = dst_type_ext;

      int16_type.width *= 2;

      int16_type.length /= 2;

      int16_type.sign = 1;

      int32_type.width *= 4;

      int32_type.length /= 4;

      int32_type.sign = 1;

      const_255f = lp_build_const_vec(gallivm, src_type, 255.0f);

      for (i = 0; i < num_dsts; ++i, src += 4) {

         LLVMValueRef lo, hi;

         for (j = 0; j < dst_type.length / 4; ++j) {

            tmp[j] = LLVMBuildFMul(builder, src[j], const_255f, "");

            tmp[j] = lp_build_iround(&bld, tmp[j]);

         }

         if (num_srcs == 1) {

            tmp[1] = tmp[0];

         }

         /* relying on clamping behavior of sse2 intrinsics here */

         lo = lp_build_pack2(gallivm, int32_type, int16_type, tmp[0], tmp[1]);

         if (num_srcs < 4) {

            hi = lo;

         }

         else {

            hi = lp_build_pack2(gallivm, int32_type, int16_type, tmp[2], tmp[3]);

         }

         dst[i] = lp_build_pack2(gallivm, int16_type, dst_type_ext, lo, hi);

      }

      if (num_srcs < 4) {

         dst[0] = lp_build_extract_range(gallivm, dst[0], 0, dst_type.length);

      }

      return;

   }

   /* Special case 2x8f --> 1x16ub, 1x8f ->1x8ub

    */

   else if (src_type.floating == 1 &&

      src_type.fixed    == 0 &&

      src_type.sign     == 1 &&

      src_type.norm     == 0 &&

      src_type.width    == 32 &&

      src_type.length   == 8 &&

      dst_type.floating == 0 &&

      dst_type.fixed    == 0 &&

      dst_type.sign     == 0 &&

      dst_type.norm     == 1 &&

      dst_type.width    == 8 &&

      ((dst_type.length == 16 && 2 * num_dsts == num_srcs) ||

       (num_dsts == 1 && dst_type.length * num_srcs == 8)) &&

      util_cpu_caps.has_avx) {

      struct lp_build_context bld;

      struct lp_type int16_type, int32_type;

      struct lp_type dst_type_ext = dst_type;

      LLVMValueRef const_255f;

      unsigned i;

      lp_build_context_init(&bld, gallivm, src_type);

      dst_type_ext.length = 16;

      int16_type = int32_type = dst_type_ext;

      int16_type.width *= 2;

      int16_type.length /= 2;

      int16_type.sign = 1;

      int32_type.width *= 4;

      int32_type.length /= 4;

      int32_type.sign = 1;

      const_255f = lp_build_const_vec(gallivm, src_type, 255.0f);

      for (i = 0; i < num_dsts; ++i, src += 2) {

         LLVMValueRef lo, hi, a, b;

         a = LLVMBuildFMul(builder, src[0], const_255f, "");

         a = lp_build_iround(&bld, a);

         tmp[0] = lp_build_extract_range(gallivm, a, 0, 4);

         tmp[1] = lp_build_extract_range(gallivm, a, 4, 4);

         /* relying on clamping behavior of sse2 intrinsics here */

         lo = lp_build_pack2(gallivm, int32_type, int16_type, tmp[0], tmp[1]);

         if (num_srcs == 1) {

            hi = lo;

         }

         else {

            b = LLVMBuildFMul(builder, src[1], const_255f, "");

            b = lp_build_iround(&bld, b);

            tmp[2] = lp_build_extract_range(gallivm, b, 0, 4);

            tmp[3] = lp_build_extract_range(gallivm, b, 4, 4);

            hi = lp_build_pack2(gallivm, int32_type, int16_type, tmp[2], tmp[3]);

         }

         dst[i] = lp_build_pack2(gallivm, int16_type, dst_type_ext, lo, hi);

      }

      if (num_srcs == 1) {

         dst[0] = lp_build_extract_range(gallivm, dst[0], 0, dst_type.length);

      }

      return;

   }

   /* Special case -> 16bit half-float

    */

   else if (dst_type.floating && dst_type.width == 16)

   {

      /* Only support src as 32bit float currently */

      assert(src_type.floating && src_type.width == 32);

      for(i = 0; i < num_tmps; ++i)

         dst[i] = lp_build_float_to_half(gallivm, tmp[i]);

      return;

   }

   /* Pre convert half-floats to floats

    */

   else if (src_type.floating && src_type.width == 16)

   {

      for(i = 0; i < num_tmps; ++i)

         tmp[i] = lp_build_half_to_float(gallivm, tmp[i]);

      tmp_type.width = 32;

   }

   /*

    * Clamp if necessary

    */

   if(memcmp(&src_type, &dst_type, sizeof src_type) != 0) {

      struct lp_build_context bld;

      double src_min = lp_const_min(src_type);

      double dst_min = lp_const_min(dst_type);

      double src_max = lp_const_max(src_type);

      double dst_max = lp_const_max(dst_type);

      LLVMValueRef thres;

      lp_build_context_init(&bld, gallivm, tmp_type);

      if(src_min < dst_min) {

         if(dst_min == 0.0)

            thres = bld.zero;

         else

            thres = lp_build_const_vec(gallivm, src_type, dst_min);

         for(i = 0; i < num_tmps; ++i)

            tmp[i] = lp_build_max(&bld, tmp[i], thres);

      }

      if(src_max > dst_max) {

         if(dst_max == 1.0)

            thres = bld.one;

         else

            thres = lp_build_const_vec(gallivm, src_type, dst_max);

         for(i = 0; i < num_tmps; ++i)

            tmp[i] = lp_build_min(&bld, tmp[i], thres);

      }

   }

   /*

    * Scale to the narrowest range

    */

   if(dst_type.floating) {

      /* Nothing to do */

   }

   else if(tmp_type.floating) {

      if(!dst_type.fixed && !dst_type.sign && dst_type.norm) {

         for(i = 0; i < num_tmps; ++i) {

            tmp[i] = lp_build_clamped_float_to_unsigned_norm(gallivm,

                                                             tmp_type,

                                                             dst_type.width,

                                                             tmp[i]);

         }

         tmp_type.floating = FALSE;

      }

      else {

         double dst_scale = lp_const_scale(dst_type);

         LLVMTypeRef tmp_vec_type;

         if (dst_scale != 1.0) {

            LLVMValueRef scale = lp_build_const_vec(gallivm, tmp_type, dst_scale);

            for(i = 0; i < num_tmps; ++i)

               tmp[i] = LLVMBuildFMul(builder, tmp[i], scale, "");

         }

         /* Use an equally sized integer for intermediate computations */

         tmp_type.floating = FALSE;

         tmp_vec_type = lp_build_vec_type(gallivm, tmp_type);

         for(i = 0; i < num_tmps; ++i) {

#if 0

            if(dst_type.sign)

               tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, "");

            else

               tmp[i] = LLVMBuildFPToUI(builder, tmp[i], tmp_vec_type, "");

#else

           /* FIXME: there is no SSE counterpart for LLVMBuildFPToUI */

            tmp[i] = LLVMBuildFPToSI(builder, tmp[i], tmp_vec_type, "");

#endif

         }

      }

   }

   else {

      unsigned src_shift = lp_const_shift(src_type);

      unsigned dst_shift = lp_const_shift(dst_type);

      unsigned src_offset = lp_const_offset(src_type);

      unsigned dst_offset = lp_const_offset(dst_type);

      /* Compensate for different offsets */

      if (dst_offset > src_offset && src_type.width > dst_type.width) {

         for (i = 0; i < num_tmps; ++i) {

            LLVMValueRef shifted;

            LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type, src_shift - 1);

            if(src_type.sign)

               shifted = LLVMBuildAShr(builder, tmp[i], shift, "");

            else

               shifted = LLVMBuildLShr(builder, tmp[i], shift, "");

            tmp[i] = LLVMBuildSub(builder, tmp[i], shifted, "");

         }

      }

      if(src_shift > dst_shift) {

         LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type,

                                                     src_shift - dst_shift);

         for(i = 0; i < num_tmps; ++i)

            if(src_type.sign)

               tmp[i] = LLVMBuildAShr(builder, tmp[i], shift, "");

            else

               tmp[i] = LLVMBuildLShr(builder, tmp[i], shift, "");

      }

   }

   /*

    * Truncate or expand bit width

    *

    * No data conversion should happen here, although the sign bits are

    * crucial to avoid bad clamping.

    */

   {

      struct lp_type new_type;

      new_type = tmp_type;

      new_type.sign   = dst_type.sign;

      new_type.width  = dst_type.width;

      new_type.length = dst_type.length;

      lp_build_resize(gallivm, tmp_type, new_type, tmp, num_srcs, tmp, num_dsts);

      tmp_type = new_type;

      num_tmps = num_dsts;

   }

   /*

    * Scale to the widest range

    */

   if(src_type.floating) {

      /* Nothing to do */

   }

   else if(!src_type.floating && dst_type.floating) {

      if(!src_type.fixed && !src_type.sign && src_type.norm) {

         for(i = 0; i < num_tmps; ++i) {

            tmp[i] = lp_build_unsigned_norm_to_float(gallivm,

                                                     src_type.width,

                                                     dst_type,

                                                     tmp[i]);

         }

         tmp_type.floating = TRUE;

      }

      else {

         double src_scale = lp_const_scale(src_type);

         LLVMTypeRef tmp_vec_type;

         /* Use an equally sized integer for intermediate computations */

         tmp_type.floating = TRUE;

         tmp_type.sign = TRUE;

         tmp_vec_type = lp_build_vec_type(gallivm, tmp_type);

         for(i = 0; i < num_tmps; ++i) {

#if 0

            if(dst_type.sign)

               tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, "");

            else

               tmp[i] = LLVMBuildUIToFP(builder, tmp[i], tmp_vec_type, "");

#else

            /* FIXME: there is no SSE counterpart for LLVMBuildUIToFP */

            tmp[i] = LLVMBuildSIToFP(builder, tmp[i], tmp_vec_type, "");

#endif

          }

          if (src_scale != 1.0) {

             LLVMValueRef scale = lp_build_const_vec(gallivm, tmp_type, 1.0/src_scale);

             for(i = 0; i < num_tmps; ++i)

                tmp[i] = LLVMBuildFMul(builder, tmp[i], scale, "");

          }

      }

    }

    else {

       unsigned src_shift = lp_const_shift(src_type);

       unsigned dst_shift = lp_const_shift(dst_type);

       unsigned src_offset = lp_const_offset(src_type);

       unsigned dst_offset = lp_const_offset(dst_type);

       if (src_shift < dst_shift) {

          LLVMValueRef pre_shift[LP_MAX_VECTOR_LENGTH];

          LLVMValueRef shift = lp_build_const_int_vec(gallivm, tmp_type, dst_shift - src_shift);

          for (i = 0; i < num_tmps; ++i) {

             pre_shift[i] = tmp[i];

             tmp[i] = LLVMBuildShl(builder, tmp[i], shift, "");

          }

          /* Compensate for different offsets */

          if (dst_offset > src_offset) {

             for (i = 0; i < num_tmps; ++i) {

                tmp[i] = LLVMBuildSub(builder, tmp[i], pre_shift[i], "");

             }

          }

       }

    }

   for(i = 0; i < num_dsts; ++i) {

      dst[i] = tmp[i];

      assert(lp_check_value(dst_type, dst[i]));

   }

}

/**

 * Bit mask conversion.

 *

 * This will convert the integer masks that match the given types.

 *

 * The mask values should 0 or -1, i.e., all bits either set to zero or one.

 * Any other value will likely cause unpredictable results.

 *

 * This is basically a very trimmed down version of lp_build_conv.

 */

void

lp_build_conv_mask(struct gallivm_state *gallivm,

                   struct lp_type src_type,

                   struct lp_type dst_type,

                   const LLVMValueRef *src, unsigned num_srcs,

                   LLVMValueRef *dst, unsigned num_dsts)

{

   /* We must not loose or gain channels. Only precision */

   assert(src_type.length * num_srcs == dst_type.length * num_dsts);

   /*

    * Drop

    *

    * We assume all values are 0 or -1

    */

   src_type.floating = FALSE;

   src_type.fixed = FALSE;

   src_type.sign = TRUE;

   src_type.norm = FALSE;

   dst_type.floating = FALSE;

   dst_type.fixed = FALSE;

   dst_type.sign = TRUE;

   dst_type.norm = FALSE;

   /*

    * Truncate or expand bit width

    */

   lp_build_resize(gallivm, src_type, dst_type, src, num_srcs, dst, num_dsts);

}