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Re: PATCH: Disable x87 inline functions for x86-64


On 06/15/2012 03:58 PM, H.J. Lu wrote:
On Thu, Jun 14, 2012 at 5:14 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
On Thu, Jun 14, 2012 at 11:19 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
On Thu, Jun 14, 2012 at 11:01 AM, Roland McGrath <roland@hack.frob.com> wrote:
I think this is probably OK, but I just don't know that much about the area.
Does this leave any function that previously had an inline and now has none?

The GCC manual seems to indicate that -mfpath=sse -msse (without -msse2)
will use x87 code for double-precision operations.  So it seems appropriate
that this mode have x87 inlines for double libm calls too.

It makes no difference for x86-64 since SSE2 is available. But it will change ia32. I think it is too late for 2.16.

Here is the updated patch to only disable x87 inline functions for x86-64.
It makes -m32 and -m64 behave the same as before.  OK to install?

Thanks.


Here is a revised patch. The output from "git diff -w" is:


diff --git a/sysdeps/i386/fpu/bits/mathinline.h
b/sysdeps/i386/fpu/bits/mathinline.h
index 5ee40a3..6446b1d 100644
--- a/sysdeps/i386/fpu/bits/mathinline.h
+++ b/sysdeps/i386/fpu/bits/mathinline.h
@@ -380,7 +380,9 @@ __NTH (floorf (float __x))
  __END_NAMESPACE_C99
  #  endif
  # endif
+#endif

+#ifndef __x86_64__
  #if ((!defined __NO_MATH_INLINES || defined __LIBC_INTERNAL_MATH_INLINES) \
       && defined __OPTIMIZE__)

@@ -963,4 +965,4 @@ __inline_mathcode2 (__ieee754_atan2, __y, __x,
  		    return __value;)
  #endif

-#endif /* __GNUC__  */
+#endif /* !__x86_64__ */

The rest is re-indenting. OK to install?


This looks fine to me.

Thanks,
Andreas
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