hppa: Fix reload error with atomic code [BZ #18787]

As noted in the bug, the asm operands need to be copied to register
variables to avoid operand reloads in the principal asm of the macro.
See the arm implementation for reference.  Otherwise we get:
../sysdeps/unix/sysv/linux/hppa/bits/atomic.h:68:6: error:
	can't find a register in class 'R1_REGS' while reloading 'asm'

Build tested on trunk with gcc-4.8.  Similar patch has been tested
with 2.19 on Debian hppa-unknown-linux-gnu.

1 files changed, 17 insertions, 18 deletions

diff --git a/sysdeps/unix/sysv/linux/hppa/bits/atomic.h b/sysdeps/unix/sysv/linux/hppa/bits/atomic.h
index abde83e2f9..6e73504fee 100644
--- a/sysdeps/unix/sysv/linux/hppa/bits/atomic.h
+++ b/sysdeps/unix/sysv/linux/hppa/bits/atomic.h
@@ -56,42 +56,41 @@ typedef uintmax_t uatomic_max_t;
 #define _LWS "0xb0"
 #define _LWS_CAS "0"
 /* Note r31 is the link register.  */
-#define _LWS_CLOBBER "r1", "r26", "r25", "r24", "r23", "r22", "r21", "r20", "r28", "r31", "memory"
+#define _LWS_CLOBBER "r1", "r23", "r22", "r20", "r31", "memory"
 /* String constant for -EAGAIN.  */
 #define _ASM_EAGAIN "-11"
 /* String constant for -EDEADLOCK.  */
 #define _ASM_EDEADLOCK "-45"
 
 #if __ASSUME_LWS_CAS
-/* The only basic operation needed is compare and exchange.  */
+/* The only basic operation needed is compare and exchange.  The mem
+   pointer must be word aligned.  */
 # define atomic_compare_and_exchange_val_acq(mem, newval, oldval)	\
   ({									\
-     volatile int lws_errno;						\
-     __typeof__ (*mem) lws_ret;						\
-     asm volatile(							\
+     register long lws_errno asm("r21");				\
+     register unsigned long lws_ret asm("r28");				\
+     register unsigned long lws_mem asm("r26") = (unsigned long)(mem);	\
+     register unsigned long lws_old asm("r25") = (unsigned long)(oldval);\
+     register unsigned long lws_new asm("r24") = (unsigned long)(newval);\
+     __asm__ __volatile__(						\
 	"0:					\n\t"			\
-	"copy	%2, %%r26			\n\t"			\
-	"copy	%3, %%r25			\n\t"			\
-	"copy	%4, %%r24			\n\t"			\
 	"ble	" _LWS "(%%sr2, %%r0)		\n\t"			\
 	"ldi	" _LWS_CAS ", %%r20		\n\t"			\
-	"ldi	" _ASM_EAGAIN ", %%r24		\n\t"			\
-	"cmpb,=,n %%r24, %%r21, 0b		\n\t"			\
+	"ldi	" _ASM_EAGAIN ", %%r20		\n\t"			\
+	"cmpb,=,n %%r20, %%r21, 0b		\n\t"			\
 	"nop					\n\t"			\
-	"ldi	" _ASM_EDEADLOCK ", %%r25	\n\t"			\
-	"cmpb,=,n %%r25, %%r21, 0b		\n\t"			\
+	"ldi	" _ASM_EDEADLOCK ", %%r20	\n\t"			\
+	"cmpb,=,n %%r20, %%r21, 0b		\n\t"			\
 	"nop					\n\t"			\
-	"stw	%%r28, %0			\n\t"			\
-	"stw	%%r21, %1			\n\t"			\
-	: "=m" (lws_ret), "=m" (lws_errno)				\
-        : "r" (mem), "r" (oldval), "r" (newval)				\
+	: "=r" (lws_ret), "=r" (lws_errno)				\
+	: "r" (lws_mem), "r" (lws_old), "r" (lws_new)			\
 	: _LWS_CLOBBER							\
      );									\
 									\
-     if(lws_errno == -EFAULT || lws_errno == -ENOSYS)			\
+     if (lws_errno == -EFAULT || lws_errno == -ENOSYS)			\
 	ABORT_INSTRUCTION;						\
 									\
-     lws_ret;								\
+     (__typeof (oldval)) lws_ret;					\
    })
 
 # define atomic_compare_and_exchange_bool_acq(mem, newval, oldval)	\