Index: CMakeLists.txt =================================================================== --- CMakeLists.txt +++ CMakeLists.txt @@ -52,6 +52,13 @@ add_definitions(-w) endif() +# Tests that use floating point math should have different tolerances when +# fast-math and fp-contract are enabled. +# TODO: Check to see if these settings are consistent with the compile options. +option(ENABLE_FAST_MATH "Allow value changing FP optimizations" OFF) +# In most cases clang uses fp-contract=on by default +option(ENABLE_FP_CONTRACT "Allow fused multiply and add instructions" ON) + # We want reproducible builds, so using __DATE__ and __TIME__ is bad add_definitions(-Werror=date-time) Index: SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/CMakeLists.txt =================================================================== --- SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/CMakeLists.txt +++ SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/CMakeLists.txt @@ -1,9 +1,13 @@ set(POLYBENCH_UTILS SingleSource/Benchmarks/Polybench/utilities ) list(APPEND CFLAGS -I ${CMAKE_SOURCE_DIR}/${POLYBENCH_UTILS} -DPOLYBENCH_DUMP_ARRAYS) set(HASH_PROGRAM_OUTPUT 1) -add_definitions(-DFP_ABSTOLERANCE=1e-5) -# Floating point contraction must be suppressed due to accuracy issues -list(APPEND CXXFLAGS -ffp-contract=off -DFMA_DISABLED=1) -list(APPEND CFLAGS -ffp-contract=off -DFMA_DISABLED=1) - +if(ENABLE_FAST_MATH) + add_definitions(-DFP_TOLERANCE=4.5e-16) + add_definitions(-DENABLE_FP_TOLERANCE_CHECK=1) +elseif(ENABLE_FP_CONTRACT) + add_definitions(-DFP_TOLERANCE=4.5e-16) + add_definitions(-DENABLE_FP_TOLERANCE_CHECK=1) +else() + add_definitions(-DFP_TOLERANCE=0.0) +endif() llvm_singlesource() Index: SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/atax.c =================================================================== --- SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/atax.c +++ SingleSource/Benchmarks/Polybench/linear-algebra/kernels/atax/atax.c @@ -77,17 +77,15 @@ } -#if !FMA_DISABLED -// NOTE: FMA_DISABLED is true for targets where FMA contraction causes -// discrepancies which cause the accuracy checks to fail. -// In this case, the test runs with the option -ffp-contract=off +#if ENABLE_FP_TOLERANCE_CHECK static void -kernel_atax_StrictFP(int nx, int ny, - DATA_TYPE POLYBENCH_2D(A,NX,NY,nx,ny), - DATA_TYPE POLYBENCH_1D(x,NY,ny), - DATA_TYPE POLYBENCH_1D(y,NY,ny), - DATA_TYPE POLYBENCH_1D(tmp,NX,nx)) +kernel_atax_ValueSafe(int nx, int ny, + DATA_TYPE POLYBENCH_2D(A,NX,NY,nx,ny), + DATA_TYPE POLYBENCH_1D(x,NY,ny), + DATA_TYPE POLYBENCH_1D(y,NY,ny), + DATA_TYPE POLYBENCH_1D(tmp,NX,nx)) { +#pragma float_control(precise, on) #pragma STDC FP_CONTRACT OFF int i, j; @@ -104,28 +102,36 @@ } /* Return 0 when one of the elements of arrays A and B do not match within the - allowed FP_ABSTOLERANCE. Return 1 when all elements match. */ + allowed FP_TOLERANCE. Return 1 when all elements match. */ static int check_FP(int ny, DATA_TYPE POLYBENCH_1D(A,NY,ny), DATA_TYPE POLYBENCH_1D(B,NY,ny)) { int i; - double AbsTolerance = FP_ABSTOLERANCE; + double RelTolerance = FP_TOLERANCE; for (i = 0; i < _PB_NY; i++) { double V1 = A[i]; double V2 = B[i]; - double Diff = fabs(V1 - V2); - if (Diff > AbsTolerance) { - fprintf(stderr, "A[%d] = %lf and B[%d] = %lf differ more than" - " FP_ABSTOLERANCE = %lf\n", i, V1, i, V2, AbsTolerance); + double RelDiff; + // If either value is zero, should we add an epsilon? + if (V2) + RelDiff = fabs(V1/V2 - 1.0); + else if (V1) + RelDiff = fabs(V2/V1 - 1.0); + else + RelDiff = 0; // Both zero. = fabs(V1/V2 - 1.0d); + if (RelDiff > RelTolerance) { + fprintf(stderr, "A[%d] = %lf and B[%d] = %lf differ by %le," + " more than FP_TOLERANCE = %le\n", i, V1, i, V2, + RelDiff, RelTolerance); return 0; } } return 1; } -#endif +#endif // ENABLE_FP_TOLERANCE_CHECK int main(int argc, char** argv) { @@ -137,9 +143,9 @@ POLYBENCH_2D_ARRAY_DECL(A, DATA_TYPE, NX, NY, nx, ny); POLYBENCH_1D_ARRAY_DECL(x, DATA_TYPE, NY, ny); POLYBENCH_1D_ARRAY_DECL(y, DATA_TYPE, NY, ny); -#if !FMA_DISABLED - POLYBENCH_1D_ARRAY_DECL(y_StrictFP, DATA_TYPE, NY, ny); -#endif +#if ENABLE_FP_TOLERANCE_CHECK + POLYBENCH_1D_ARRAY_DECL(y_ValueSafe, DATA_TYPE, NY, ny); +#endif // ENABLE_FP_TOLERANCE_CHECK POLYBENCH_1D_ARRAY_DECL(tmp, DATA_TYPE, NX, nx); /* Initialize array(s). */ @@ -159,30 +165,30 @@ polybench_stop_instruments; polybench_print_instruments; -#if FMA_DISABLED +#if !ENABLE_FP_TOLERANCE_CHECK /* Prevent dead-code elimination. All live-out data must be printed by the function call in argument. */ polybench_prevent_dce(print_array(nx, POLYBENCH_ARRAY(y))); -#else - kernel_atax_StrictFP (nx, ny, +#else // ENABLE_FP_TOLERANCE_CHECK + kernel_atax_ValueSafe (nx, ny, POLYBENCH_ARRAY(A), POLYBENCH_ARRAY(x), - POLYBENCH_ARRAY(y_StrictFP), + POLYBENCH_ARRAY(y_ValueSafe), POLYBENCH_ARRAY(tmp)); - if (!check_FP(ny, POLYBENCH_ARRAY(y), POLYBENCH_ARRAY(y_StrictFP))) + if (!check_FP(ny, POLYBENCH_ARRAY(y), POLYBENCH_ARRAY(y_ValueSafe))) return 1; /* Prevent dead-code elimination. All live-out data must be printed by the function call in argument. */ - polybench_prevent_dce(print_array(nx, POLYBENCH_ARRAY(y_StrictFP))); -#endif + polybench_prevent_dce(print_array(nx, POLYBENCH_ARRAY(y_ValueSafe))); +#endif // ENABLE_FP_TOLERANCE_CHECK /* Be clean. */ POLYBENCH_FREE_ARRAY(A); POLYBENCH_FREE_ARRAY(x); POLYBENCH_FREE_ARRAY(y); -#if !FMA_DISABLED - POLYBENCH_FREE_ARRAY(y_StrictFP); +#if ENABLE_FP_TOLERANCE_CHECK + POLYBENCH_FREE_ARRAY(y_ValueSafe); #endif POLYBENCH_FREE_ARRAY(tmp);