Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
jlebar marked 2 inline comments as done. jlebar added a comment. Repository: rL LLVM http://reviews.llvm.org/D20457 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
jlebar added a comment. Thank you for the review! http://reviews.llvm.org/D20457 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
This revision was automatically updated to reflect the committed changes. Closed by commit rL270279: Update -ffast-math documentation to match reality. (authored by jlebar). Changed prior to commit: http://reviews.llvm.org/D20457?vs=57958=57995#toc Repository: rL LLVM http://reviews.llvm.org/D20457 Files: cfe/trunk/docs/UsersManual.rst cfe/trunk/include/clang/Basic/LangOptions.def cfe/trunk/include/clang/Driver/Options.td Index: cfe/trunk/include/clang/Driver/Options.td === --- cfe/trunk/include/clang/Driver/Options.td +++ cfe/trunk/include/clang/Driver/Options.td @@ -592,9 +592,7 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Allow aggressive, lossy floating-point optimizations">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: cfe/trunk/include/clang/Basic/LangOptions.def === --- cfe/trunk/include/clang/Basic/LangOptions.def +++ cfe/trunk/include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "fast FP math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") Index: cfe/trunk/docs/UsersManual.rst === --- cfe/trunk/docs/UsersManual.rst +++ cfe/trunk/docs/UsersManual.rst @@ -1055,6 +1055,19 @@ the behavior of sanitizers in the ``cfi`` group to allow checking of cross-DSO virtual and indirect calls. +.. option:: -ffast-math + + Enable fast-math mode. This defines the ``__FAST_MATH__`` preprocessor + macro, and lets the compiler make aggressive, potentially-lossy assumptions + about floating-point math. These include: + + * Floating-point math obeys regular algebraic rules for real numbers (e.g. + ``+`` and ``*`` are associative, ``x/y == x * (1/y)``, and + ``(a + b) * c == a * c + b * c``), + * operands to floating-point operations are not equal to ``NaN`` and + ``Inf``, and + * ``+0`` and ``-0`` are interchangeable. + .. option:: -fwhole-program-vtables Enable whole-program vtable optimizations, such as single-implementation Index: cfe/trunk/include/clang/Driver/Options.td === --- cfe/trunk/include/clang/Driver/Options.td +++ cfe/trunk/include/clang/Driver/Options.td @@ -592,9 +592,7 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Allow aggressive, lossy floating-point optimizations">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: cfe/trunk/include/clang/Basic/LangOptions.def === --- cfe/trunk/include/clang/Basic/LangOptions.def +++ cfe/trunk/include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "fast FP math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") Index: cfe/trunk/docs/UsersManual.rst
Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
rsmith accepted this revision. This revision is now accepted and ready to land. Comment at: docs/UsersManual.rst:1067 @@ +1066,3 @@ + ``(a + b) * c == a * c + b * c``), + * operands to fp operations are not equal to ``NaN`` and ``Inf``, and + * ``+0`` and ``-0`` are interchangeable. fp -> floating-point Comment at: include/clang/Basic/LangOptions.def:165 @@ -164,3 +164,3 @@ COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "fast fp math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") fp -> FP http://reviews.llvm.org/D20457 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
jlebar updated this revision to Diff 57958. jlebar added a comment. Update per Richard's review. http://reviews.llvm.org/D20457 Files: docs/UsersManual.rst include/clang/Basic/LangOptions.def include/clang/Driver/Options.td Index: include/clang/Driver/Options.td === --- include/clang/Driver/Options.td +++ include/clang/Driver/Options.td @@ -592,9 +592,7 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Allow aggressive, lossy floating-point optimizations">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: include/clang/Basic/LangOptions.def === --- include/clang/Basic/LangOptions.def +++ include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "fast fp math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") Index: docs/UsersManual.rst === --- docs/UsersManual.rst +++ docs/UsersManual.rst @@ -1055,6 +1055,18 @@ the behavior of sanitizers in the ``cfi`` group to allow checking of cross-DSO virtual and indirect calls. +.. option:: -ffast-math + + Enable fast-math mode. This defines the ``__FAST_MATH__`` preprocessor + macro, and lets the compiler make aggressive, potentially-lossy assumptions + about floating-point math. These include: + + * Floating-point math obeys regular algebraic rules for real numbers (e.g. + ``+`` and ``*`` are associative, ``x/y == x * (1/y)``, and + ``(a + b) * c == a * c + b * c``), + * operands to fp operations are not equal to ``NaN`` and ``Inf``, and + * ``+0`` and ``-0`` are interchangeable. + .. option:: -fwhole-program-vtables Enable whole-program vtable optimizations, such as single-implementation Index: include/clang/Driver/Options.td === --- include/clang/Driver/Options.td +++ include/clang/Driver/Options.td @@ -592,9 +592,7 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Allow aggressive, lossy floating-point optimizations">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: include/clang/Basic/LangOptions.def === --- include/clang/Basic/LangOptions.def +++ include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "fast fp math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") Index: docs/UsersManual.rst === --- docs/UsersManual.rst +++ docs/UsersManual.rst @@ -1055,6 +1055,18 @@ the behavior of sanitizers in the ``cfi`` group to allow checking of cross-DSO virtual and indirect calls. +.. option:: -ffast-math + + Enable fast-math mode. This defines the ``__FAST_MATH__`` preprocessor + macro, and lets the compiler make aggressive, potentially-lossy assumptions
Re: [PATCH] D20457: Update -ffast-math documentation to match reality.
On Thu, May 19, 2016 at 6:11 PM, Justin Lebar via cfe-commits < cfe-commits@lists.llvm.org> wrote: > jlebar created this revision. > jlebar added a reviewer: rsmith. > jlebar added a subscriber: cfe-commits. > > http://reviews.llvm.org/D20457 > > Files: > include/clang/Basic/LangOptions.def > include/clang/Driver/Options.td > > Index: include/clang/Driver/Options.td > === > --- include/clang/Driver/Options.td > +++ include/clang/Driver/Options.td > @@ -592,9 +592,13 @@ > def : Flag<["-"], "fno-extended-identifiers">, Group, > Flags<[Unsupported]>; > def fhosted : Flag<["-"], "fhosted">, Group; > def ffast_math : Flag<["-"], "ffast-math">, Group, > Flags<[CC1Option]>, > - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect > on " > - "optimizations, but provides a preprocessor macro > __FAST_MATH__ the " > - "same as GCC's -ffast-math flag">; > + HelpText<"Enable fast-math mode. This defines the __FAST_MATH__ > preprocessor " > + "macro, and lets the compiler make aggressive, potentially > unsafe " > + "assumptions about floating-point math. These include: " > + "Floating-point math obeys regular algebraic rules for real " > + "numbers (e.g. + and * are associative, and x/y == x * (1/y)), > " > + "operands to fp operations are not equal to NaN and Inf, and > +0 " > + "and -0 are interchangeable.">; > This is significantly too long for HelpText. The current help text for this flag is already too long: $ clang --help [...] -fembed-bitcode Embed LLVM IR bitcode as data -femit-all-declsEmit all declarations, even if unused -femulated-tls Use emutls functions to access thread_local variables -fexceptionsEnable support for exception handling -ffast-math Enable the *frontend*'s 'fast-math' mode. This has no effect on optimizations, but provides a preprocessor macro __FAST_MATH__ the same as GCC's -ffast-math flag -ffixed-r9 Reserve the r9 register (ARM only) -ffixed-x18 Reserve the x18 register (AArch64 only) [...] Can you move this to UsersManual.rst instead, and put something short here instead, like "Allow aggressive, lossy floating-point optimizations"? def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; > def fmath_errno : Flag<["-"], "fmath-errno">, Group, > Flags<[CC1Option]>, >HelpText<"Require math functions to indicate errors by setting errno">; > Index: include/clang/Basic/LangOptions.def > === > --- include/clang/Basic/LangOptions.def > +++ include/clang/Basic/LangOptions.def > @@ -162,7 +162,7 @@ > COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") > COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined > macro") > COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined > macro") > -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined > macro") > +COMPATIBLE_LANGOPT(FastMath , 1, 0, "Fast fp math optimizations, > and __FAST_MATH__ predefined macro") > Something like "fast FP math [...]" would fit better into the diagnostics where this appears. > COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ > predefined macro") > COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") > > > > > ___ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > > ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D20457: Update -ffast-math documentation to match reality.
jlebar created this revision. jlebar added a reviewer: rsmith. jlebar added a subscriber: cfe-commits. http://reviews.llvm.org/D20457 Files: include/clang/Basic/LangOptions.def include/clang/Driver/Options.td Index: include/clang/Driver/Options.td === --- include/clang/Driver/Options.td +++ include/clang/Driver/Options.td @@ -592,9 +592,13 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Enable fast-math mode. This defines the __FAST_MATH__ preprocessor " + "macro, and lets the compiler make aggressive, potentially unsafe " + "assumptions about floating-point math. These include: " + "Floating-point math obeys regular algebraic rules for real " + "numbers (e.g. + and * are associative, and x/y == x * (1/y)), " + "operands to fp operations are not equal to NaN and Inf, and +0 " + "and -0 are interchangeable.">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: include/clang/Basic/LangOptions.def === --- include/clang/Basic/LangOptions.def +++ include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "Fast fp math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") Index: include/clang/Driver/Options.td === --- include/clang/Driver/Options.td +++ include/clang/Driver/Options.td @@ -592,9 +592,13 @@ def : Flag<["-"], "fno-extended-identifiers">, Group, Flags<[Unsupported]>; def fhosted : Flag<["-"], "fhosted">, Group; def ffast_math : Flag<["-"], "ffast-math">, Group, Flags<[CC1Option]>, - HelpText<"Enable the *frontend*'s 'fast-math' mode. This has no effect on " - "optimizations, but provides a preprocessor macro __FAST_MATH__ the " - "same as GCC's -ffast-math flag">; + HelpText<"Enable fast-math mode. This defines the __FAST_MATH__ preprocessor " + "macro, and lets the compiler make aggressive, potentially unsafe " + "assumptions about floating-point math. These include: " + "Floating-point math obeys regular algebraic rules for real " + "numbers (e.g. + and * are associative, and x/y == x * (1/y)), " + "operands to fp operations are not equal to NaN and Inf, and +0 " + "and -0 are interchangeable.">; def fno_fast_math : Flag<["-"], "fno-fast-math">, Group; def fmath_errno : Flag<["-"], "fmath-errno">, Group, Flags<[CC1Option]>, HelpText<"Require math functions to indicate errors by setting errno">; Index: include/clang/Basic/LangOptions.def === --- include/clang/Basic/LangOptions.def +++ include/clang/Basic/LangOptions.def @@ -162,7 +162,7 @@ COMPATIBLE_LANGOPT(GNUInline , 1, 0, "GNU inline semantics") COMPATIBLE_LANGOPT(NoInlineDefine, 1, 0, "__NO_INLINE__ predefined macro") COMPATIBLE_LANGOPT(Deprecated, 1, 0, "__DEPRECATED predefined macro") -COMPATIBLE_LANGOPT(FastMath , 1, 0, "__FAST_MATH__ predefined macro") +COMPATIBLE_LANGOPT(FastMath , 1, 0, "Fast fp math optimizations, and __FAST_MATH__ predefined macro") COMPATIBLE_LANGOPT(FiniteMathOnly, 1, 0, "__FINITE_MATH_ONLY__ predefined macro") COMPATIBLE_LANGOPT(UnsafeFPMath , 1, 0, "Unsafe Floating Point Math") ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
