src/gromacs/simd/tests/simd.h

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  36 #ifndef GMX_SIMD_TESTS_SIMD_H
  37 #define GMX_SIMD_TESTS_SIMD_H
  38
  39 /*! \internal \file
  40  * \brief
  41  * Declares fixture for testing of normal SIMD (not SIMD4) functionality.
  42  *
  43  * The SIMD tests are both simple and complicated. The actual testing logic
  44  * is \a very straightforward since we just need to test single values against
  45  * the math library, and for some math functions we need to do it in a loop.
  46  * This could have been achieved in minutes with the default Google Test tools,
  47  * if it wasn't for the problem that we cannot access or compare SIMD contents
  48  * directly without using lots of other SIMD functionality. For this reason
  49  * we have separate the basic testing of load/store operations into a separate
  50  * bootstrapping test. Once this works, we use a set of utility routines to
  51  * convert SIMD contents to/from std:vector<> and perform the rest of the tests,
  52  * which then can farmed out to the base class SimdBaseTest that is common
  53  * to SIMD and SIMD4.
  54  *
  55  * Another complication is that the width of the SIMD implementation will
  56  * depend on the hardware and precision. For some simple operations it is
  57  * sufficient to set all SIMD elements to the same value, and check that the
  58  * result is present in all elements. However, for a few more complex
  59  * instructions that might rely on shuffling under-the-hood it is important
  60  * that we can test operations with different elements. We achieve this by
  61  * having test code that can initialize a SIMD variable from an std::vector
  62  * of arbitrary length; the vector is simply repeated to fill all elements in
  63  * the SIMD variable. We also have similar routines to compare a SIMD result
  64  * with values in a vector, which returns true iff all elements match.
  65  *
  66  * This way we can write simple tests that use different values for all SIMD
  67  * elements. Personally I like using vectors of length 3, since this means
  68  * there are no simple repeated patterns in low/high halves of SIMD variables
  69  * that are 2,4,8,or 16 elements wide, and we still don't have to care about
  70  * the exact SIMD width of the underlying implementation.
  71  *
  72  * Note that this utility uses a few SIMD load/store instructions internally -
  73  * those have been tested separately in the bootstrap_loadstore.cpp file.
  74  *
  75  * \author Erik Lindahl <erik.lindahl@scilifelab.se>
  76  * \ingroup module_simd
  77  */
  78 #include <vector>
  79
  80 #include <gtest/gtest.h>
  81
  82 #include "gromacs/simd/simd.h"
  83
  84 #include "base.h"
  85 #include "data.h"
  86
  87 #if GMX_SIMD
  88
  89 namespace gmx
  90 {
  91 namespace test
  92 {
  93
  94
  95 /*! \cond internal */
  96 /*! \addtogroup module_simd */
  97 /*! \{ */
  98
  99 /* Unfortunately we cannot keep static SIMD constants in the test fixture class.
 100  * The problem is that SIMD memory need to be aligned, and in particular
 101  * this applies to automatic storage of variables in classes. For SSE registers
 102  * this means 16-byte alignment (which seems to work), but AVX requires 32-bit
 103  * alignment. At least both gcc-4.7.3 and Apple clang-5.0 (OS X 10.9) fail to
 104  * align these variables when they are stored as data in a class.
 105  *
 106  * In theory we could set some of these on-the-fly e.g. with setSimdFrom3R()
 107  * instead (although that would mean repeating code between tests), but many of
 108  * the constants depend on the current precision not to mention they
 109  * occasionally have many digits that need to be exactly right, and keeping
 110  * them in a single place makes sure they are consistent.
 111  */
 112 #    if GMX_SIMD_HAVE_REAL
 113 extern const SimdReal rSimd_c0c1c2; //!< c0,c1,c2 repeated
 114 extern const SimdReal rSimd_c3c4c5; //!< c3,c4,c5 repeated
 115 extern const SimdReal rSimd_c6c7c8; //!< c6,c7,c8 repeated
 116 extern const SimdReal rSimd_c3c0c4; //!< c3,c0,c4 repeated
 117 extern const SimdReal rSimd_c4c6c8; //!< c4,c6,c8 repeated
 118 extern const SimdReal rSimd_c7c2c3; //!< c7,c2,c3 repeated
 119 extern const SimdReal rSimd_m0m1m2; //!< -c0,-c1,-c2 repeated
 120 extern const SimdReal rSimd_m3m0m4; //!< -c3,-c0,-c4 repeated
 121
 122 extern const SimdReal rSimd_2p25;  //!< Value that rounds down.
 123 extern const SimdReal rSimd_3p25;  //!< Value that rounds down.
 124 extern const SimdReal rSimd_3p75;  //!< Value that rounds up.
 125 extern const SimdReal rSimd_m2p25; //!< Negative value that rounds up.
 126 extern const SimdReal rSimd_m3p25; //!< Negative value that rounds up.
 127 extern const SimdReal rSimd_m3p75; //!< Negative value that rounds down.
 128 //! Three large floating-point values whose exponents are >32.
 129 extern const SimdReal rSimd_Exp;
 130
 131 #        if GMX_SIMD_HAVE_LOGICAL
 132 extern const SimdReal rSimd_logicalA;         //!< Bit pattern to test logical ops
 133 extern const SimdReal rSimd_logicalB;         //!< Bit pattern to test logical ops
 134 extern const SimdReal rSimd_logicalResultOr;  //!< Result or bitwise 'or' of A and B
 135 extern const SimdReal rSimd_logicalResultAnd; //!< Result or bitwise 'and' of A and B
 136 #        endif                                // GMX_SIMD_HAVE_LOGICAL
 137
 138 #        if GMX_SIMD_HAVE_DOUBLE && GMX_DOUBLE
 139 // Make sure we also test exponents outside single precision when we use double
 140 extern const SimdReal rSimd_ExpDouble1;
 141 extern const SimdReal rSimd_ExpDouble2;
 142 #        endif
 143 // Magic FP numbers corresponding to specific bit patterns
 144 extern const SimdReal rSimd_Bits1; //!< Pattern F0 repeated to fill single/double.
 145 extern const SimdReal rSimd_Bits2; //!< Pattern CC repeated to fill single/double.
 146 extern const SimdReal rSimd_Bits3; //!< Pattern C0 repeated to fill single/double.
 147 extern const SimdReal rSimd_Bits4; //!< Pattern 0C repeated to fill single/double.
 148 extern const SimdReal rSimd_Bits5; //!< Pattern FC repeated to fill single/double.
 149 extern const SimdReal rSimd_Bits6; //!< Pattern 3C repeated to fill single/double.
 150 #    endif                         // GMX_SIMD_HAVE_REAL
 151 #    if GMX_SIMD_HAVE_INT32_ARITHMETICS
 152 extern const SimdInt32 iSimd_1_2_3;    //!< Three generic ints.
 153 extern const SimdInt32 iSimd_4_5_6;    //!< Three generic ints.
 154 extern const SimdInt32 iSimd_7_8_9;    //!< Three generic ints.
 155 extern const SimdInt32 iSimd_5_7_9;    //!< iSimd_1_2_3 + iSimd_4_5_6.
 156 extern const SimdInt32 iSimd_1M_2M_3M; //!< Term1 for 32bit add/sub.
 157 extern const SimdInt32 iSimd_4M_5M_6M; //!< Term2 for 32bit add/sub.
 158 extern const SimdInt32 iSimd_5M_7M_9M; //!< iSimd_1M_2M_3M + iSimd_4M_5M_6M.
 159 #    endif
 160 #    if GMX_SIMD_HAVE_INT32_LOGICAL
 161 extern const SimdInt32 iSimd_0xF0F0F0F0; //!< Bitpattern to test integer logical operations.
 162 extern const SimdInt32 iSimd_0xCCCCCCCC; //!< Bitpattern to test integer logical operations.
 163 #    endif
 164
 165
 166 /*! \internal
 167  * \brief
 168  * Test fixture for SIMD tests.
 169  *
 170  * This is a very simple test fixture that basically just takes the common
 171  * SIMD/SIMD4 functionality from SimdBaseTest and creates wrapper routines
 172  * specific for normal SIMD functionality.
 173  */
 174 class SimdTest : public SimdBaseTest
 175 {
 176 public:
 177 #    if GMX_SIMD_HAVE_REAL
 178     /*! \brief Compare two real SIMD variables for approximate equality.
 179      *
 180      * This is an internal implementation routine. YOu should always use
 181      * GMX_EXPECT_SIMD_REAL_NEAR() instead.
 182      *
 183      * This routine is designed according to the Google test specs, so the char
 184      * strings will describe the arguments to the macro.
 185      *
 186      * The comparison is applied to each element, and it returns true if each element
 187      * in the SIMD test variable is within the class tolerances of the corresponding
 188      * reference element.
 189      */
 190
 191
 192     ::testing::AssertionResult
 193     compareSimdRealUlp(const char* refExpr, const char* tstExpr, SimdReal ref, SimdReal tst);
 194
 195     /*! \brief Compare two real SIMD variables for exact equality.
 196      *
 197      * This is an internal implementation routine. YOu should always use
 198      * GMX_EXPECT_SIMD_REAL_NEAR() instead.
 199      *
 200      * This routine is designed according to the Google test specs, so the char
 201      * strings will describe the arguments to the macro.
 202      *
 203      * The comparison is applied to each element, and it returns true if each element
 204      * in the SIMD test variable is within the class tolerances of the corresponding
 205      * reference element.
 206      */
 207     ::testing::AssertionResult compareSimdEq(const char* refExpr, const char* tstExpr, SimdReal ref, SimdReal tst);
 208
 209     /*! \brief Compare two 32-bit integer SIMD variables.
 210      *
 211      * This is an internal implementation routine. YOu should always use
 212      * GMX_EXPECT_SIMD_INT_EQ() instead.
 213      *
 214      * This routine is designed according to the Google test specs, so the char
 215      * strings will describe the arguments to the macro, while the SIMD and
 216      * tolerance arguments are used to decide if the values are approximately equal.
 217      *
 218      * The comparison is applied to each element, and it returns true if each element
 219      * in the SIMD variable tst is identical to the corresponding reference element.
 220      */
 221     ::testing::AssertionResult compareSimdEq(const char* refExpr, const char* tstExpr, SimdInt32 ref, SimdInt32 tst);
 222 #    endif
 223 };
 224
 225 #    if GMX_SIMD_HAVE_REAL
 226 /*! \brief Convert SIMD real to std::vector<real>.
 227  *
 228  * The returned vector will have the same length as the SIMD width.
 229  */
 230 std::vector<real> simdReal2Vector(SimdReal simd);
 231
 232 /*! \brief Return floating-point SIMD value from std::vector<real>.
 233  *
 234  * If the vector is longer than SIMD width, only the first elements will be used.
 235  * If it is shorter, the contents will be repeated to fill the SIMD register.
 236  */
 237 SimdReal vector2SimdReal(const std::vector<real>& v);
 238
 239 /*! \brief Set SIMD register contents from three real values.
 240  *
 241  * Our reason for using three values is that 3 is not a factor in any known
 242  * SIMD width, so this way there will not be any simple repeated patterns e.g.
 243  * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 244  */
 245 SimdReal setSimdRealFrom3R(real r0, real r1, real r2);
 246
 247 /*! \brief Set SIMD register contents from single real value.
 248  *
 249  * All elements is set from the given value. This is effectively the same
 250  * operation as simdSet1(), but is implemented using only load/store
 251  * operations that have been tested separately in the bootstrapping tests.
 252  */
 253 SimdReal setSimdRealFrom1R(real value);
 254
 255 /*! \brief Test if a SIMD real is bitwise identical to reference SIMD value. */
 256 #        define GMX_EXPECT_SIMD_REAL_EQ(ref, tst) EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 257
 258 /*! \brief Test if a SIMD is bitwise identical to reference SIMD value. */
 259 #        define GMX_EXPECT_SIMD_EQ(ref, tst) EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 260
 261 /*! \brief Test if a SIMD real is within tolerance of reference SIMD value. */
 262 #        define GMX_EXPECT_SIMD_REAL_NEAR(ref, tst) \
 263             EXPECT_PRED_FORMAT2(compareSimdRealUlp, ref, tst)
 264
 265 /*! \brief Convert SIMD integer to std::vector<int>.
 266  *
 267  * The returned vector will have the same length as the SIMD width.
 268  */
 269 std::vector<std::int32_t> simdInt2Vector(SimdInt32 simd);
 270
 271 /*! \brief Return 32-bit integer SIMD value from std::vector<int>.
 272  *
 273  * If the vector is longer than SIMD width, only the first elements will be used.
 274  * If it is shorter, the contents will be repeated to fill the SIMD register.
 275  */
 276 SimdInt32 vector2SimdInt(const std::vector<std::int32_t>& v);
 277
 278 /*! \brief Set SIMD register contents from three int values.
 279  *
 280  * Our reason for using three values is that 3 is not a factor in any known
 281  * SIMD width, so this way there will not be any simple repeated patterns e.g.
 282  * between the low/high 64/128/256 bits in the SIMD register, which could hide bugs.
 283  */
 284 SimdInt32 setSimdIntFrom3I(int i0, int i1, int i2);
 285
 286 /*! \brief Set SIMD register contents from single integer value.
 287  *
 288  * All elements is set from the given value. This is effectively the same
 289  * operation as simdSet1I(), but is implemented using only load/store
 290  * operations that have been tested separately in the bootstrapping tests.
 291  */
 292 SimdInt32 setSimdIntFrom1I(int value);
 293
 294 /*! \brief Macro that checks SIMD integer expression against SIMD or reference int.
 295  *
 296  * If the reference argument is a scalar integer it will be expanded into
 297  * the width of the SIMD register and tested against all elements.
 298  */
 299 #        define GMX_EXPECT_SIMD_INT_EQ(ref, tst) EXPECT_PRED_FORMAT2(compareSimdEq, ref, tst)
 300
 301 #    endif // GMX_SIMD_HAVE_REAL
 302
 303 /*! \} */
 304 /*! \endcond */
 305
 306 } // namespace test
 307 } // namespace gmx
 308
 309 #endif // GMX_SIMD
 310
 311 #endif // GMX_SIMD_TESTS_SIMD_H