[PATCH] D72841: [RFC] Add support for pragma float_control, to control precision and exception behavior at the source level

[Melanie Blower via Phabricator via cfe-commits]

mibintc updated this revision to Diff 243888.
mibintc added a comment.
Herald added subscribers: kbarton, jvesely, nemanjai.

This patch is a work in progress.

The problem that I want to work on next is that the scope is wrong when the pragma token is seen following the right brace of a function body. In this patch I worked around that problem by modifying the test case to insert bogus "class ResetScope;" to force the scope back to file-level before each pragma that occurs at file scope. You can see that workaround in the test case clang/test/CodeGen/fp-floatcontrol-stack.cpp

These are the main differences with previous version of this patch:

1. per Andy Kaylor's comments in the llvm-dev discussion "Floating Point semantic modes", I changed the -ffp-model=precise to be the default. I changed ffp-model=precise to set -ffp-contract=on [previously it was -ffp-contract=fast].  This caused the need to change some tests because the LLVM IR now has the "contract" bit enabled.
2. I put FMF into the FPOptions struct.  As I mentioned in a previous comment, I have a request to allow changing the REASSOC bit via source pragma. I plan to submit that in a separate patch.  Putting FMF into FPOptions allows the fast bits to be set or disabled via pragma float_control precise, Andy had suggested this change in his code review.
3. I put Andy's distillation of floating point options and floating point modes into UsersManual.rst
4. I changed how the strictfp attribute was set on functions, now it's set if the strict mode is enabled in the function body e.g. either by the option level or a float_control pragma

Still needs to be done:

1. The problem with the file scope I mentioned above
2. I assume that the 2 denormal settings need to be added to FPOptions.
3. Required diagnostics a la MSVC that Andy mentioned in llvm-dev discussion "Floating Point semantic modes"
4. What else?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72841/new/

https://reviews.llvm.org/D72841

Files:
  clang/docs/LanguageExtensions.rst
  clang/docs/UsersManual.rst
  clang/include/clang/AST/Stmt.h
  clang/include/clang/Basic/DiagnosticParseKinds.td
  clang/include/clang/Basic/LangOptions.def
  clang/include/clang/Basic/LangOptions.h
  clang/include/clang/Basic/PragmaKinds.h
  clang/include/clang/Basic/TokenKinds.def
  clang/include/clang/Parse/Parser.h
  clang/include/clang/Sema/Sema.h
  clang/lib/CodeGen/CGExprScalar.cpp
  clang/lib/CodeGen/CodeGenFunction.cpp
  clang/lib/CodeGen/CodeGenFunction.h
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/lib/Parse/ParseDeclCXX.cpp
  clang/lib/Parse/ParsePragma.cpp
  clang/lib/Parse/ParseStmt.cpp
  clang/lib/Parse/Parser.cpp
  clang/lib/Sema/Sema.cpp
  clang/lib/Sema/SemaAttr.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/lib/Sema/SemaStmt.cpp
  clang/test/CodeGen/constrained-math-builtins.c
  clang/test/CodeGen/fast-math.c
  clang/test/CodeGen/fp-contract-on-pragma.cpp
  clang/test/CodeGen/fp-contract-pragma.cpp
  clang/test/CodeGen/fp-floatcontrol-class.cpp
  clang/test/CodeGen/fp-floatcontrol-pragma.cpp
  clang/test/CodeGen/fp-floatcontrol-stack.cpp
  clang/test/CodeGen/fpconstrained.c
  clang/test/CodeGen/fpconstrained.cpp
  clang/test/CodeGen/ppc-emmintrin.c
  clang/test/CodeGen/ppc-xmmintrin.c
  clang/test/CodeGenOpenCL/builtins-amdgcn-dl-insts.cl
  clang/test/CodeGenOpenCL/builtins-amdgcn-gfx9.cl
  clang/test/CodeGenOpenCL/builtins-amdgcn-interp.cl
  clang/test/CodeGenOpenCL/builtins-amdgcn-mfma.cl
  clang/test/CodeGenOpenCL/builtins-amdgcn-vi.cl
  clang/test/CodeGenOpenCL/builtins-amdgcn.cl
  clang/test/CodeGenOpenCL/builtins-f16.cl
  clang/test/CodeGenOpenCL/builtins-r600.cl
  clang/test/CodeGenOpenCL/relaxed-fpmath.cl
  clang/test/CodeGenOpenCL/single-precision-constant.cl
  clang/test/Driver/fp-model.c
  clang/test/Parser/fp-floatcontrol-syntax.cpp
  llvm/include/llvm/IR/IRBuilder.h

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