src/gromacs/simd/tests/simd.h

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   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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  35 #ifndef GMX_SIMD_TESTS_SIMD_H
  36 #define GMX_SIMD_TESTS_SIMD_H
  37
  38 /*! \internal \file
  39  * \brief
  40  * Declares fixture for testing of normal SIMD (not SIMD4) functionality.
  41  *
  42  * The SIMD tests are both simple and complicated. The actual testing logic
  43  * is \a very straightforward since we just need to test single values against
  44  * the math library, and for some math functions we need to do it in a loop.
  45  * This could have been achieved in minutes with the default Google Test tools,
  46  * if it wasn't for the problem that we cannot access or compare SIMD contents
  47  * directly without using lots of other SIMD functionality. For this reason
  48  * we have separate the basic testing of load/store operations into a separate
  49  * bootstrapping test. Once this works, we use a set of utility routines to
  50  * convert SIMD contents to/from std:vector<> and perform the rest of the tests,
  51  * which then can farmed out to the base class SimdBaseTest that is common
  52  * to SIMD and SIMD4.
  53  *
  54  * Another complication is that the width of the SIMD implementation will
  55  * depend on the hardware and precision. For some simple operations it is
  56  * sufficient to set all SIMD elements to the same value, and check that the
  57  * result is present in all elements. However, for a few more complex
  58  * instructions that might rely on shuffling under-the-hood it is important
  59  * that we can test operations with different elements. We achieve this by
  60  * having test code that can initialize a SIMD variable from an std::vector
  61  * of arbitrary length; the vector is simply repeated to fill all elements in
  62  * the SIMD variable. We also have similar routines to compare a SIMD result
  63  * with values in a vector, which returns true iff all elements match.
  64  *
  65  * This way we can write simple tests that use different values for all SIMD
  66  * elements. Personally I like using vectors of length 3, since this means
  67  * there are no simple repeated patterns in low/high halves of SIMD variables
  68  * that are 2,4,8,or 16 elements wide, and we still don't have to care about
  69  * the exact SIMD width of the underlying implementation.
  70  *
  71  * Note that this utility uses a few SIMD load/store instructions internally -
  72  * those have been tested separately in the bootstrap_loadstore.cpp file.
  73  *
  74  * \author Erik Lindahl <erik.lindahl@scilifelab.se>
  75  * \ingroup module_simd
  76  */
  77 #include <vector>
  78
  79 #include <gtest/gtest.h>
  80
  81 #include "gromacs/simd/simd.h"
  82
  83 #include "base.h"
  84 #include "data.h"
  85
  86 #if GMX_SIMD
  87
  88 namespace gmx
  89 {
  90 namespace test
  91 {
  92
  93
  94 /*! \cond internal */
  95 /*! \addtogroup module_simd */
  96 /*! \{ */
  97
  98 /* Unfortunately we cannot keep static SIMD constants in the test fixture class.
  99  * The problem is that SIMD memory need to be aligned, and in particular
 100  * this applies to automatic storage of variables in classes. For SSE registers
 101  * this means 16-byte alignment (which seems to work), but AVX requires 32-bit
 102  * alignment. At least both gcc-4.7.3 and Apple clang-5.0 (OS X 10.9) fail to
 103  * align these variables when they are stored as data in a class.
 104  *
 105  * In theory we could set some of these on-the-fly e.g. with setSimdFrom3R()
 106  * instead (although that would mean repeating code between tests), but many of
 107  * the constants depend on the current precision not to mention they
 108  * occasionally have many digits that need to be exactly right, and keeping
 109  * them in a single place makes sure they are consistent.
 110  */
 111 #if GMX_SIMD_HAVE_REAL
 112 extern const SimdReal rSimd_c0c1c2;    //!< c0,c1,c2 repeated
 113 extern const SimdReal rSimd_c3c4c5;    //!< c3,c4,c5 repeated
 114 extern const SimdReal rSimd_c6c7c8;    //!< c6,c7,c8 repeated
 115 extern const SimdReal rSimd_c3c0c4;    //!< c3,c0,c4 repeated
 116 extern const SimdReal rSimd_c4c6c8;    //!< c4,c6,c8 repeated
 117 extern const SimdReal rSimd_c7c2c3;    //!< c7,c2,c3 repeated
 118 extern const SimdReal rSimd_m0m1m2;    //!< -c0,-c1,-c2 repeated
 119 extern const SimdReal rSimd_m3m0m4;    //!< -c3,-c0,-c4 repeated
 120
 121 extern const SimdReal rSimd_2p25;      //!< Value that rounds down.
 122 extern const SimdReal rSimd_3p25;      //!< Value that rounds down.
 123 extern const SimdReal rSimd_3p75;      //!< Value that rounds up.
 124 extern const SimdReal rSimd_m2p25;     //!< Negative value that rounds up.
 125 extern const SimdReal rSimd_m3p25;     //!< Negative value that rounds up.
 126 extern const SimdReal rSimd_m3p75;     //!< Negative value that rounds down.
 127 //! Three large floating-point values whose exponents are >32.
 128 extern const SimdReal rSimd_Exp;
 129
 130 #if GMX_SIMD_HAVE_LOGICAL
 131 extern const SimdReal rSimd_logicalA;         //!< Bit pattern to test logical ops
 132 extern const SimdReal rSimd_logicalB;         //!< Bit pattern to test logical ops
 133 extern const SimdReal rSimd_logicalResultOr;  //!< Result or bitwise 'or' of A and B
 134 extern const SimdReal rSimd_logicalResultAnd; //!< Result or bitwise 'and' of A and B
 135 #endif                                        // GMX_SIMD_HAVE_LOGICAL
 136
 137 #    if GMX_SIMD_HAVE_DOUBLE && GMX_DOUBLE
 138 // Make sure we also test exponents outside single precision when we use double
 139 extern const SimdReal rSimd_ExpDouble;
 140 #    endif
 141 // Magic FP numbers corresponding to specific bit patterns
 142 extern const SimdReal rSimd_Bits1;       //!< Pattern F0 repeated to fill single/double.
 143 extern const SimdReal rSimd_Bits2;       //!< Pattern CC repeated to fill single/double.
 144 extern const SimdReal rSimd_Bits3;       //!< Pattern C0 repeated to fill single/double.
 145 extern const SimdReal rSimd_Bits4;       //!< Pattern 0C repeated to fill single/double.
 146 extern const SimdReal rSimd_Bits5;       //!< Pattern FC repeated to fill single/double.
 147 extern const SimdReal rSimd_Bits6;       //!< Pattern 3C repeated to fill single/double.
 148 #endif                                   // GMX_SIMD_HAVE_REAL
 149 #if GMX_SIMD_HAVE_INT32_ARITHMETICS
 150 extern const SimdInt32 iSimd_1_2_3;      //!< Three generic ints.
 151 extern const SimdInt32 iSimd_4_5_6;      //!< Three generic ints.
 152 extern const SimdInt32 iSimd_7_8_9;      //!< Three generic ints.
 153 extern const SimdInt32 iSimd_5_7_9;      //!< iSimd_1_2_3 + iSimd_4_5_6.
 154 extern const SimdInt32 iSimd_1M_2M_3M;   //!< Term1 for 32bit add/sub.
 155 extern const SimdInt32 iSimd_4M_5M_6M;   //!< Term2 for 32bit add/sub.
 156 extern const SimdInt32 iSimd_5M_7M_9M;   //!< iSimd_1M_2M_3M + iSimd_4M_5M_6M.
 157 #endif
 158 #if GMX_SIMD_HAVE_INT32_LOGICAL
 159 extern const SimdInt32 iSimd_0xF0F0F0F0; //!< Bitpattern to test integer logical operations.
 160 extern const SimdInt32 iSimd_0xCCCCCCCC; //!< Bitpattern to test integer logical operations.
 161 #endif
 162
 163
 164 /*! \internal
 165  * \brief
 166  * Test fixture for SIMD tests.
 167  *
 168  * This is a very simple test fixture that basically just takes the common
 169  * SIMD/SIMD4 functionality from SimdBaseTest and creates wrapper routines
 170  * specific for normal SIMD functionality.
 171  */
 172 class SimdTest : public SimdBaseTest
 173 {
 174     public:
 175 #if GMX_SIMD_HAVE_REAL
 176         /*! \brief Compare two real SIMD variables for approximate equality.
 177          *
 178          * This is an internal implementation routine. YOu should always use
 179          * GMX_EXPECT_SIMD_REAL_NEAR() instead.
 180          *
 181          * This routine is designed according to the Google test specs, so the char
 182          * strings will describe the arguments to the macro.
 183          *
 184          * The comparison is applied to each element, and it returns true if each element
 185          * in the SIMD test variable is within the class tolerances of the corresponding
 186          * reference element.
 187          */
 188
 189
 190             ::testing::AssertionResult
 191         compareSimdRealUlp(const char * refExpr, const char * tstExpr,
 192                            const SimdReal ref, const SimdReal tst);
 193
 194         /*! \brief Compare two real SIMD variables for exact equality.
 195          *
 196          * This is an internal implementation routine. YOu should always use
 197          * GMX_EXPECT_SIMD_REAL_NEAR() instead.
 198          *
 199          * This routine is designed according to the Google test specs, so the char
 200          * strings will describe the arguments to the macro.
 201          *
 202          * The comparison is applied to each element, and it returns true if each element
 203          * in the SIMD test variable is within the class tolerances of the corresponding
 204          * reference element.
 205          */
 206         ::testing::AssertionResult
 207         compareSimdEq(const char * refExpr, const char * tstExpr,
 208                       const SimdReal ref, const SimdReal tst);
 209
 210         /*! \brief Compare two 32-bit integer SIMD variables.
 211          *
 212          * This is an internal implementation routine. YOu should always use
 213          * GMX_EXPECT_SIMD_INT_EQ() instead.
 214          *
 215          * This routine is designed according to the Google test specs, so the char
 216          * strings will describe the arguments to the macro, while the SIMD and
 217          * tolerance arguments are used to decide if the values are approximately equal.
 218          *
 219          * The comparison is applied to each element, and it returns true if each element
 220          * in the SIMD variable tst is identical to the corresponding reference element.
 221          */
 222         ::testing::AssertionResult
 223         compareSimdEq(const char * refExpr, const char *  tstExpr,
 224                       const SimdInt32 ref, const SimdInt32 tst);
 225 #endif
 226 };
 227
 228 #if GMX_SIMD_HAVE_REAL
 229 /*! \brief Convert SIMD real to std::vector<real>.
 230  *
 231  * The returned vector will have the same length as the SIMD width.
 232  */
 233 std::vector<real> simdReal2Vector(const SimdReal simd);
 234
 235 /*! \brief Return floating-point SIMD value from std::vector<real>.
 236  *
 237  * If the vector is longer than SIMD width, only the first elements will be used.
 238  * If it is shorter, the contents will be repeated to fill the SIMD register.
 239  */
 240 SimdReal   vector2SimdReal(const std::vector<real> &v);
 241
 242 /*! \brief Set SIMD register contents from three real values.
 243  *
 244  * Our reason for using three values is that 3 is not a factor in any known
 245  * SIMD width, so this way there will not be any simple repeated patterns e.g.
 246  * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 247  */
 248 SimdReal   setSimdRealFrom3R(real r0, real r1, real r2);
 249
 250 /*! \brief Set SIMD register contents from single real value.
 251  *
 252  * All elements is set from the given value. This is effectively the same
 253  * operation as simdSet1(), but is implemented using only load/store
 254  * operations that have been tested separately in the bootstrapping tests.
 255  */
 256 SimdReal   setSimdRealFrom1R(real value);
 257
 258 /*! \brief Test if a SIMD real is bitwise identical to reference SIMD value. */
 259 #define GMX_EXPECT_SIMD_REAL_EQ(ref, tst)   EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 260
 261 /*! \brief Test if a SIMD is bitwise identical to reference SIMD value. */
 262 #define GMX_EXPECT_SIMD_EQ(ref, tst)   EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 263
 264 /*! \brief Test if a SIMD real is within tolerance of reference SIMD value. */
 265 #define GMX_EXPECT_SIMD_REAL_NEAR(ref, tst) EXPECT_PRED_FORMAT2(compareSimdRealUlp, ref, tst)
 266
 267 /*! \brief Convert SIMD integer to std::vector<int>.
 268  *
 269  * The returned vector will have the same length as the SIMD width.
 270  */
 271 std::vector<int>   simdInt2Vector(const SimdInt32 simd);
 272
 273 /*! \brief Return 32-bit integer SIMD value from std::vector<int>.
 274  *
 275  * If the vector is longer than SIMD width, only the first elements will be used.
 276  * If it is shorter, the contents will be repeated to fill the SIMD register.
 277  */
 278 SimdInt32   vector2SimdInt(const std::vector<int> &v);
 279
 280 /*! \brief Set SIMD register contents from three int values.
 281  *
 282  * Our reason for using three values is that 3 is not a factor in any known
 283  * SIMD width, so this way there will not be any simple repeated patterns e.g.
 284  * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 285  */
 286 SimdInt32   setSimdIntFrom3I(int i0, int i1, int i2);
 287
 288 /*! \brief Set SIMD register contents from single integer value.
 289  *
 290  * All elements is set from the given value. This is effectively the same
 291  * operation as simdSet1I(), but is implemented using only load/store
 292  * operations that have been tested separately in the bootstrapping tests.
 293  */
 294 SimdInt32   setSimdIntFrom1I(int value);
 295
 296 /*! \brief Macro that checks SIMD integer expression against SIMD or reference int.
 297  *
 298  * If the reference argument is a scalar integer it will be expanded into
 299  * the width of the SIMD register and tested against all elements.
 300  */
 301 #define GMX_EXPECT_SIMD_INT_EQ(ref, tst)    EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 302
 303 #endif  // GMX_SIMD_HAVE_REAL
 304
 305 /*! \} */
 306 /*! \endcond */
 307
 308 }      // namespace
 309 }      // namespace
 310
 311 #endif // GMX_SIMD
 312
 313 #endif // GMX_SIMD_TESTS_SIMD_H