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| author | Joseph Myers <joseph@codesourcery.com> | 2021-09-15 22:57:35 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2021-09-15 22:57:35 +0000 |
| commit | 4b6574a6f63b6c766f27be4a0b4c9376a35a4bd5 (patch) | |
| tree | ba1ed4258b6617f7fbde8ef9a0665fdf859cb955 /math | |
| parent | 5604830dea207bbd5fd5dbe087cc7ca30b527bb5 (diff) | |
| download | glibc-4b6574a6f63b6c766f27be4a0b4c9376a35a4bd5.tar.gz glibc-4b6574a6f63b6c766f27be4a0b4c9376a35a4bd5.tar.xz glibc-4b6574a6f63b6c766f27be4a0b4c9376a35a4bd5.zip | |
Redirect fma calls to __fma in libm
include/math.h has a mechanism to redirect internal calls to various libm functions, that can often be inlined by the compiler, to call non-exported __* names for those functions in the case when the calls aren't inlined, with the redirection being disabled when NO_MATH_REDIRECT. Add fma to the functions to which this mechanism is applied. At present, libm-internal fma calls (generally to __builtin_fma* functions) are only done when it's known the call will be inlined, with alternative code not relying on an fma operation being used in the caller otherwise. This patch is in preparation for adding the TS 18661 / C2X narrowing fma functions to glibc; it will be natural for the narrowing function implementations to call the underlying fma functions unconditionally, with this either being inlined or resulting in an __fma* call. (Using two levels of round-to-odd computation like that, in the case where there isn't an fma hardware instruction, isn't optimal but is certainly a lot simpler for the initial implementation than writing different narrowing fma implementations for all the various pairs of formats.) Tested with build-many-glibcs.py that installed stripped shared libraries are unchanged by the patch (using <https://sourceware.org/pipermail/libc-alpha/2021-September/130991.html> to fix installed library stripping in build-many-glibcs.py). Also tested for x86_64.
Diffstat (limited to 'math')
| -rw-r--r-- | math/s_fma.c | 1 | ||||
| -rw-r--r-- | math/s_fmaf.c | 1 | ||||
| -rw-r--r-- | math/s_fmal.c | 1 |
3 files changed, 3 insertions, 0 deletions
diff --git a/math/s_fma.c b/math/s_fma.c index 5b0afde6b8..2dc5c5d2cb 100644 --- a/math/s_fma.c +++ b/math/s_fma.c @@ -16,6 +16,7 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ +#define NO_MATH_REDIRECT #include <math.h> #include <libm-alias-double.h> diff --git a/math/s_fmaf.c b/math/s_fmaf.c index 401f0fc5ae..f1ba0a0c49 100644 --- a/math/s_fmaf.c +++ b/math/s_fmaf.c @@ -16,6 +16,7 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ +#define NO_MATH_REDIRECT #include <math.h> #include <libm-alias-float.h> diff --git a/math/s_fmal.c b/math/s_fmal.c index 6b13ea1d5f..47a68ed235 100644 --- a/math/s_fmal.c +++ b/math/s_fmal.c @@ -16,6 +16,7 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ +#define NO_MATH_REDIRECT #include <math.h> #include <libm-alias-ldouble.h> |