https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91638
Carl Love <cel at us dot ibm.com> changed:
What |Removed |Added
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CC| |cel at us dot ibm.com
--- Comment #3 from Carl Love <cel at us dot ibm.com> ---
I have looked at what -mlong-double-64 and -mlong-double-128 do.
The -mlong-double-64 tells GCC to use the 64-bit IEEE floating point format.
The -mlong-double-128 tells GCC to use 128-bit floating point format. On
ppc64, there are actually two 128-bit floating point formats that are
supported. So it looks to me like the user should also specify either
-mabi=ieeelongdouble to get the 128-bit IEEE floating point format or
-mabi=ibmlongdouble to get the IBM 128-bit floating point format.
I created a patch that updates the output of the gcc --target-help command to
print the following:
-mlong-double- Use -mlong-double-64 for 64-bit IEEE floating
point format. Use -mlong-double-128 and
-mabi=ieeelongdouble for 128-bit IEEE floating
point format. Use -mlong-double-128 and
-mabi=ibmlongdouble for 128-bit IBM floating
point format.
Please let me know if this description is accurate and better. Suggestions on
improvements are always welcome.
