The Intel compiler supports the option "-fp-model=(source|double|extended)" which causes the compiler to use a wider type for intermediate floating point calculations. Also supported is a way to embed this effect in the source program with #pragma float_control(source|double|extended). This patch proposes to extend pragma float_control syntax, and also to support a new floating point option via "-ffp-eval-method=(source|double|extended)"
Note that the C floating point working group has proposed nearly identical pragma semantics in http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1974.pdf like this
#pragma STDC FENV_FLT_EVAL_METHOD width
I would like to add support for this also, but it's not in this patch.
I'm going to add an inline question about how to redefine FLT_EVAL_METHOD macro
The ICL option with description of semantics is at this url, https://software.intel.com/content/www/us/en/develop/documentation/cpp-compiler-developer-guide-and-reference/top/compiler-reference/compiler-options/compiler-option-details/floating-point-options/fp-model-fp.html