lround: provide cast for wordsize-64 version if needed

Platforms with 64-bit registers where 32-bit values need to have the
high 32 bits set in a particular way need to have an explicit cast
when using the 64-bit sysdeps/ieee754/dbl-64/wordsize-64 version
of llround() as lround().  This includes tilegx32, and likely MIPS.
x32 does not need this, and AArch64 ILP32 will not either.  Require
it to be specified in sysdep.h to be explicit.

diff --git a/ChangeLog b/ChangeLog
index 0e6e224..123b0b2 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2015-01-05  Chris Metcalf  <cmetcalf@ezchip.com>
+
+       * sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c [!defined _LP64
+       && REGISTER_CAST_INT32_TO_INT64]: Provide explicit lround()
+       function with cast from llround().
+       * sysdeps/tile/sysdep.h (REGISTER_CAST_INT32_TO_INT64): Define.
+       * sysdeps/x86_64/x32/sysdep.h (REGISTER_CAST_INT32_TO_INT64):
+       Define.
+
 2015-01-05  Joseph Myers  <joseph@codesourcery.com>
 
        [BZ #17793]

diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c
index 8852601..8bb5252 100644 (file)
--- a/sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c
@@ -21,6 +21,7 @@
 #define __lround __hidden___lround
 
 #include <math.h>
+#include <sysdep.h>
 
 #include <math_private.h>
 
@@ -64,16 +65,31 @@ __llround (double x)
 
 weak_alias (__llround, llround)
 #ifdef NO_LONG_DOUBLE
-strong_alias (__llround, __lroundl)
-weak_alias (__llround, lroundl)
+strong_alias (__llround, __llroundl)
+weak_alias (__llround, llroundl)
 #endif
 
-/* long has the same width as long long on 64-bit machines.  */
+/* long has the same width as long long on LP64 machines, so use an alias.
+   If building for ILP32 on a machine with 64-bit registers, however,
+   use a cast if necessary.  */
 #undef lround
 #undef __lround
+#if !defined (_LP64) && REGISTER_CAST_INT32_TO_INT64
+long int
+__lround (double x)
+{
+  return __llround (x);
+}
+weak_alias (__lround, lround)
+# ifdef NO_LONG_DOUBLE
+strong_alias (__lround, __lroundl)
+weak_alias (__lround, lroundl)
+# endif
+#else
 strong_alias (__llround, __lround)
 weak_alias (__llround, lround)
-#ifdef NO_LONG_DOUBLE
-strong_alias (__llround, __llroundl)
-weak_alias (__llround, llroundl)
+# ifdef NO_LONG_DOUBLE
+strong_alias (__llround, __lroundl)
+weak_alias (__llround, lroundl)
+# endif
 #endif

diff --git a/sysdeps/tile/sysdep.h b/sysdeps/tile/sysdep.h
index ead9dba..7b3d873 100644 (file)
--- a/sysdeps/tile/sysdep.h
+++ b/sysdeps/tile/sysdep.h
@@ -108,3 +108,7 @@
 #endif
 
 #endif /* __ASSEMBLER__ */
+
+/* On tilegx, 32-bit values must have their high 32 bits sign extended;
+   random values are not allowed.  */
+#define REGISTER_CAST_INT32_TO_INT64 1

diff --git a/sysdeps/x86_64/x32/sysdep.h b/sysdeps/x86_64/x32/sysdep.h
index 9b87005..0cbc1a0 100644 (file)
--- a/sysdeps/x86_64/x32/sysdep.h
+++ b/sysdeps/x86_64/x32/sysdep.h
@@ -90,3 +90,7 @@
 # define R15_LP        "r15d"
 
 #endif /* __ASSEMBLER__ */
+
+/* On x32, it is not required to normalize a 64-bit value before using
+   it as a 32-bit value.  */
+#define REGISTER_CAST_INT32_TO_INT64 0