FIX validate for PPC Mac OS X - Evac.h

1 files changed, 10 insertions, 1 deletions

diff --git a/rts/sm/Evac.h b/rts/sm/Evac.h
index c0aeeb546d..beaba755c1 100644
--- a/rts/sm/Evac.h
+++ b/rts/sm/Evac.h
@@ -12,7 +12,16 @@
  * ---------------------------------------------------------------------------*/
 
 // Use a register argument for evacuate, if available.
-#if __GNUC__ >= 2
+// Earlier, the regparm attribute was used whenever __GNUC__ >= 2, but this
+// generated warnings on PPC. So the use is restricted further.
+// See http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html that says
+//     regparm (number)
+//         On the Intel 386, the regparm attribute causes the compiler to pass
+//         arguments number one to number if they are of integral type in
+//         registers EAX, EDX, and ECX instead of on the stack. Functions that
+//         take a variable number of arguments will continue to be passed all of
+//         their arguments on the stack.
+#if __GNUC__ >= 2 && (defined(x86_64_TARGET_ARCH) || defined(i386_TARGET_ARCH))
 #define REGPARM1 __attribute__((regparm(1)))
 #else
 #define REGPARM1