powerpc/math-emu: Update macros from GCC

The add_ssaaaa, sub_ddmmss, umul_ppmm and udiv_qrnnd macros originate
from GCC's longlong.h which in turn was copied from GMP's longlong.h a
few decades ago.

This was found when compiling with clang:

arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
FP_ADD_D(R, T, B);
^~~~~~~~~~~~~~~~~
...

./arch/powerpc/include/asm/sfp-machine.h:283:27: note: expanded from
macro 'sub_ddmmss'
: "=r" ((USItype)(sh)), \
~~~~~~~~~~^~~

Segher points out: this was fixed in GCC over 16 years ago
( https://gcc.gnu.org/r56600 ), and in GMP (where it comes from)
presumably before that.

Update the add_ssaaaa, sub_ddmmss, umul_ppmm and udiv_qrnnd macros to
the latest GCC version in order to git rid of the invalid casts. These
were taken as-is from GCC's longlong in order to make future syncs
obvious. Other parts of sfp-machine.h were left as-is as the file
contains more features than present in longlong.h.

Link: https://github.com/ClangBuiltLinux/linux/issues/260
Signed-off-by: Joel Stanley <[e-mail]>
Reviewed-by: Nick Desaulniers <[e-mail]>
Reviewed-by: Segher Boessenkool <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/include/asm/sfp-machine.h

···
  * respectively.  The result is placed in HIGH_SUM and LOW_SUM.  Overflow
  * (i.e. carry out) is not stored anywhere, and is lost.
  */
-#define add_ssaaaa(sh, sl, ah, al, bh, bl)				\
+#define add_ssaaaa(sh, sl, ah, al, bh, bl) \
   do {									\
     if (__builtin_constant_p (bh) && (bh) == 0)				\
-      __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{aze|addze} %0,%2"		\
-	     : "=r" ((USItype)(sh)),					\
-	       "=&r" ((USItype)(sl))					\
-	     : "%r" ((USItype)(ah)),					\
-	       "%r" ((USItype)(al)),					\
-	       "rI" ((USItype)(bl)));					\
-    else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)		\
-      __asm__ ("{a%I4|add%I4c} %1,%3,%4\n\t{ame|addme} %0,%2"		\
-	     : "=r" ((USItype)(sh)),					\
-	       "=&r" ((USItype)(sl))					\
-	     : "%r" ((USItype)(ah)),					\
-	       "%r" ((USItype)(al)),					\
-	       "rI" ((USItype)(bl)));					\
+      __asm__ ("add%I4c %1,%3,%4\n\taddze %0,%2"		\
+	     : "=r" (sh), "=&r" (sl) : "r" (ah), "%r" (al), "rI" (bl));\
+    else if (__builtin_constant_p (bh) && (bh) == ~(USItype) 0)		\
+      __asm__ ("add%I4c %1,%3,%4\n\taddme %0,%2"		\
+	     : "=r" (sh), "=&r" (sl) : "r" (ah), "%r" (al), "rI" (bl));\
     else								\
-      __asm__ ("{a%I5|add%I5c} %1,%4,%5\n\t{ae|adde} %0,%2,%3"		\
-	     : "=r" ((USItype)(sh)),					\
-	       "=&r" ((USItype)(sl))					\
-	     : "%r" ((USItype)(ah)),					\
-	       "r" ((USItype)(bh)),					\
-	       "%r" ((USItype)(al)),					\
-	       "rI" ((USItype)(bl)));					\
+      __asm__ ("add%I5c %1,%4,%5\n\tadde %0,%2,%3"		\
+	     : "=r" (sh), "=&r" (sl)					\
+	     : "%r" (ah), "r" (bh), "%r" (al), "rI" (bl));		\
   } while (0)
 
 /* sub_ddmmss is used in op-2.h and udivmodti4.c and should be equivalent to
···
  * and LOW_DIFFERENCE.  Overflow (i.e. carry out) is not stored anywhere,
  * and is lost.
  */
-#define sub_ddmmss(sh, sl, ah, al, bh, bl)				\
+#define sub_ddmmss(sh, sl, ah, al, bh, bl) \
   do {									\
     if (__builtin_constant_p (ah) && (ah) == 0)				\
-      __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfze|subfze} %0,%2"	\
-	       : "=r" ((USItype)(sh)),					\
-		 "=&r" ((USItype)(sl))					\
-	       : "r" ((USItype)(bh)),					\
-		 "rI" ((USItype)(al)),					\
-		 "r" ((USItype)(bl)));					\
-    else if (__builtin_constant_p (ah) && (ah) ==~(USItype) 0)		\
-      __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{sfme|subfme} %0,%2"	\
-	       : "=r" ((USItype)(sh)),					\
-		 "=&r" ((USItype)(sl))					\
-	       : "r" ((USItype)(bh)),					\
-		 "rI" ((USItype)(al)),					\
-		 "r" ((USItype)(bl)));					\
+      __asm__ ("subf%I3c %1,%4,%3\n\tsubfze %0,%2"	\
+	       : "=r" (sh), "=&r" (sl) : "r" (bh), "rI" (al), "r" (bl));\
+    else if (__builtin_constant_p (ah) && (ah) == ~(USItype) 0)		\
+      __asm__ ("subf%I3c %1,%4,%3\n\tsubfme %0,%2"	\
+	       : "=r" (sh), "=&r" (sl) : "r" (bh), "rI" (al), "r" (bl));\
     else if (__builtin_constant_p (bh) && (bh) == 0)			\
-      __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{ame|addme} %0,%2"		\
-	       : "=r" ((USItype)(sh)),					\
-		 "=&r" ((USItype)(sl))					\
-	       : "r" ((USItype)(ah)),					\
-		 "rI" ((USItype)(al)),					\
-		 "r" ((USItype)(bl)));					\
-    else if (__builtin_constant_p (bh) && (bh) ==~(USItype) 0)		\
-      __asm__ ("{sf%I3|subf%I3c} %1,%4,%3\n\t{aze|addze} %0,%2"		\
-	       : "=r" ((USItype)(sh)),					\
-		 "=&r" ((USItype)(sl))					\
-	       : "r" ((USItype)(ah)),					\
-		 "rI" ((USItype)(al)),					\
-		 "r" ((USItype)(bl)));					\
+      __asm__ ("subf%I3c %1,%4,%3\n\taddme %0,%2"		\
+	       : "=r" (sh), "=&r" (sl) : "r" (ah), "rI" (al), "r" (bl));\
+    else if (__builtin_constant_p (bh) && (bh) == ~(USItype) 0)		\
+      __asm__ ("subf%I3c %1,%4,%3\n\taddze %0,%2"		\
+	       : "=r" (sh), "=&r" (sl) : "r" (ah), "rI" (al), "r" (bl));\
     else								\
-      __asm__ ("{sf%I4|subf%I4c} %1,%5,%4\n\t{sfe|subfe} %0,%3,%2"	\
-	       : "=r" ((USItype)(sh)),					\
-		 "=&r" ((USItype)(sl))					\
-	       : "r" ((USItype)(ah)),					\
-		 "r" ((USItype)(bh)),					\
-		 "rI" ((USItype)(al)),					\
-		 "r" ((USItype)(bl)));					\
+      __asm__ ("subf%I4c %1,%5,%4\n\tsubfe %0,%3,%2"	\
+	       : "=r" (sh), "=&r" (sl)					\
+	       : "r" (ah), "r" (bh), "rI" (al), "r" (bl));		\
   } while (0)
 
 /* asm fragments for mul and div */
···
  * UWtype integers MULTIPLER and MULTIPLICAND, and generates a two UWtype
  * word product in HIGH_PROD and LOW_PROD.
  */
-#define umul_ppmm(ph, pl, m0, m1)					\
+#define umul_ppmm(ph, pl, m0, m1) \
   do {									\
     USItype __m0 = (m0), __m1 = (m1);					\
-    __asm__ ("mulhwu %0,%1,%2"						\
-	     : "=r" ((USItype)(ph))					\
-	     : "%r" (__m0),						\
-               "r" (__m1));						\
+    __asm__ ("mulhwu %0,%1,%2" : "=r" (ph) : "%r" (m0), "r" (m1));	\
     (pl) = __m0 * __m1;							\
   } while (0)
 
···
  * significant bit of DENOMINATOR must be 1, then the pre-processor symbol
  * UDIV_NEEDS_NORMALIZATION is defined to 1.
  */
-#define udiv_qrnnd(q, r, n1, n0, d)					\
+#define udiv_qrnnd(q, r, n1, n0, d) \
   do {									\
-    UWtype __d1, __d0, __q1, __q0, __r1, __r0, __m;			\
+    UWtype __d1, __d0, __q1, __q0;					\
+    UWtype __r1, __r0, __m;						\
     __d1 = __ll_highpart (d);						\
     __d0 = __ll_lowpart (d);						\
 									\
···
     if (__r1 < __m)							\
       {									\
 	__q1--, __r1 += (d);						\
-	if (__r1 >= (d)) /* we didn't get carry when adding to __r1 */	\
+	if (__r1 >= (d)) /* i.e. we didn't get carry when adding to __r1 */\
 	  if (__r1 < __m)						\
 	    __q1--, __r1 += (d);					\
       }									\