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Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math and the Fortran-specific -fno-protect-parens and -fstack-arrays.
Enable handling of OpenMP directives "#pragma omp" in C/C++ and
"!$omp" in Fortran. When -fopenmp is specified, the compiler
generates parallel code according to the OpenMP Application
Program Interface v4.0
Enable handling of OpenMP's SIMD directives with "#pragma omp" in C/C++ and "!$omp" in Fortran. Other OpenMP directives are ignored.
Generate code for 32-bit or 64-bit ABI.
Intel AVX-512 Foundation instructions (AVX-512F) are the base of Intel AVX-512. They include extensions of the Intel AVX and Intel AVX2 family of SIMD instructions but are encoded using EVEX encoding scheme with support for 512-bit vector registers, up to 32 vector registers in 64-bit mode, and conditional processing using opmask registers.
Intel AVX-512 Conflict Detection instructions (AVX-512CD) provide efficient conflict detection to allow more loops to be vectorized.
Intel AVX-512 Exponential and Reciprocal instructions (AVX-512ER) are designed to provide building blocks for accelerating certain transcendental math computations.
Intel AVX-512 Prefetch instructions (AVX-512PF) are new instructions that can be useful for reducing memory operation latency exposure that involve gather/scatter instructions.
Generate instructions for Intel's Ivy Bridge CPU. In contrast to -mtune=cpu-type, which merely tunes the generated code for the specified cpu-type, -march=cpu-type allows GCC to generate code that may not run at all on processors other than the one indicated. Specifying -march=cpu-type implies -mtune=cpu-type.
Intel Ivy Bridge CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, POPCNT, AVX, AES, PCLMUL, FSGSBASE, RDRND and F16C instruction set support.
Invoke the GNU C compiler
Invoke the GNU C++ compiler
Invoke the GNU Fortran compiler