[PATCH] D93769: RFC [clang] Add support for option -ffp-eval-method and extend #pragma float_control similarly

[Melanie Blower via Phabricator via cfe-commits]

mibintc created this revision.
mibintc added reviewers: kpn, sepavloff, andrew.w.kaylor, rjmccall.
Herald added subscribers: dexonsmith, dang.
mibintc requested review of this revision.
Herald added a project: clang.

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


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93769

Files:
  clang/docs/LanguageExtensions.rst
  clang/docs/UsersManual.rst
  clang/include/clang/Basic/FPOptions.def
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Basic/LangOptions.h
  clang/include/clang/Basic/PragmaKinds.h
  clang/include/clang/Driver/Options.td
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Parse/ParsePragma.cpp
  clang/lib/Sema/SemaAttr.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/test/CodeGen/fp-floatcontrol-pragma.cpp

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