[v2] lib/mpi: Eliminate unused umul_ppmm definitions for MIPS
diff mbox series

Message ID 20190812193256.55103-1-natechancellor@gmail.com
State Accepted
Delegated to: Herbert Xu
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Series
  • [v2] lib/mpi: Eliminate unused umul_ppmm definitions for MIPS
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Commit Message

Nathan Chancellor Aug. 12, 2019, 7:32 p.m. UTC
Clang errors out when building this macro:

lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
                umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
                ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm'
        : "=l" ((USItype)(w0)), \
                ~~~~~~~~~~^~~
lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h'
in asm
                umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
                ^
lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm'
             "=h" ((USItype)(w1)) \
             ^
2 errors generated.

The C version that is used for GCC 4.4 and up works well with clang;
however, it is not currently being used because Clang masks itself
as GCC 4.2.1 for compatibility reasons. As Nick points out, we require
GCC 4.6 and newer in the kernel so we can eliminate all of the
versioning checks and just use the C version of umul_ppmm for all
supported compilers.

Link: https://github.com/ClangBuiltLinux/linux/issues/605
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

This supersedes the following two patches:

https://lore.kernel.org/lkml/20190812033120.43013-4-natechancellor@gmail.com/

https://lore.kernel.org/lkml/20190812033120.43013-5-natechancellor@gmail.com/

I labelled this as a v2 so those don't get applied.

 lib/mpi/longlong.h | 36 +-----------------------------------
 1 file changed, 1 insertion(+), 35 deletions(-)

Comments

Nick Desaulniers Aug. 12, 2019, 7:37 p.m. UTC | #1
On Mon, Aug 12, 2019 at 12:36 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> Clang errors out when building this macro:
>
> lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a
> inline asm context requiring an l-value: remove the cast or build with
> -fheinous-gnu-extensions
>                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
>                 ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm'
>         : "=l" ((USItype)(w0)), \
>                 ~~~~~~~~~~^~~
> lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h'
> in asm
>                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
>                 ^
> lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm'
>              "=h" ((USItype)(w1)) \
>              ^
> 2 errors generated.
>
> The C version that is used for GCC 4.4 and up works well with clang;
> however, it is not currently being used because Clang masks itself
> as GCC 4.2.1 for compatibility reasons. As Nick points out, we require
> GCC 4.6 and newer in the kernel so we can eliminate all of the
> versioning checks and just use the C version of umul_ppmm for all
> supported compilers.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/605
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

LGTM thanks Nathan.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>
> This supersedes the following two patches:
>
> https://lore.kernel.org/lkml/20190812033120.43013-4-natechancellor@gmail.com/
>
> https://lore.kernel.org/lkml/20190812033120.43013-5-natechancellor@gmail.com/
>
> I labelled this as a v2 so those don't get applied.
>
>  lib/mpi/longlong.h | 36 +-----------------------------------
>  1 file changed, 1 insertion(+), 35 deletions(-)
>
> diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
> index 3bb6260d8f42..2dceaca27489 100644
> --- a/lib/mpi/longlong.h
> +++ b/lib/mpi/longlong.h
> @@ -639,30 +639,12 @@ do { \
>         **************  MIPS  *****************
>         ***************************************/
>  #if defined(__mips__) && W_TYPE_SIZE == 32
> -#if (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
>  #define umul_ppmm(w1, w0, u, v)                        \
>  do {                                           \
>         UDItype __ll = (UDItype)(u) * (v);      \
>         w1 = __ll >> 32;                        \
>         w0 = __ll;                              \
>  } while (0)
> -#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7
> -#define umul_ppmm(w1, w0, u, v) \
> -       __asm__ ("multu %2,%3" \
> -       : "=l" ((USItype)(w0)), \
> -            "=h" ((USItype)(w1)) \
> -       : "d" ((USItype)(u)), \
> -            "d" ((USItype)(v)))
> -#else
> -#define umul_ppmm(w1, w0, u, v) \
> -       __asm__ ("multu %2,%3\n" \
> -          "mflo %0\n" \
> -          "mfhi %1" \
> -       : "=d" ((USItype)(w0)), \
> -            "=d" ((USItype)(w1)) \
> -       : "d" ((USItype)(u)), \
> -            "d" ((USItype)(v)))
> -#endif
>  #define UMUL_TIME 10
>  #define UDIV_TIME 100
>  #endif /* __mips__ */
> @@ -687,7 +669,7 @@ do {                                                                        \
>                  : "d" ((UDItype)(u)),                                  \
>                    "d" ((UDItype)(v)));                                 \
>  } while (0)
> -#elif (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
> +#else
>  #define umul_ppmm(w1, w0, u, v) \
>  do {                                                                   \
>         typedef unsigned int __ll_UTItype __attribute__((mode(TI)));    \
> @@ -695,22 +677,6 @@ do {                                                                       \
>         w1 = __ll >> 64;                                                \
>         w0 = __ll;                                                      \
>  } while (0)
> -#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7
> -#define umul_ppmm(w1, w0, u, v) \
> -       __asm__ ("dmultu %2,%3" \
> -       : "=l" ((UDItype)(w0)), \
> -            "=h" ((UDItype)(w1)) \
> -       : "d" ((UDItype)(u)), \
> -            "d" ((UDItype)(v)))
> -#else
> -#define umul_ppmm(w1, w0, u, v) \
> -       __asm__ ("dmultu %2,%3\n" \
> -          "mflo %0\n" \
> -          "mfhi %1" \
> -       : "=d" ((UDItype)(w0)), \
> -            "=d" ((UDItype)(w1)) \
> -       : "d" ((UDItype)(u)), \
> -            "d" ((UDItype)(v)))
>  #endif
>  #define UMUL_TIME 20
>  #define UDIV_TIME 140
> --
> 2.23.0.rc2
>
Herbert Xu Aug. 22, 2019, 5:55 a.m. UTC | #2
On Mon, Aug 12, 2019 at 12:32:57PM -0700, Nathan Chancellor wrote:
> Clang errors out when building this macro:
> 
> lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a
> inline asm context requiring an l-value: remove the cast or build with
> -fheinous-gnu-extensions
>                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
>                 ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm'
>         : "=l" ((USItype)(w0)), \
>                 ~~~~~~~~~~^~~
> lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h'
> in asm
>                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
>                 ^
> lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm'
>              "=h" ((USItype)(w1)) \
>              ^
> 2 errors generated.
> 
> The C version that is used for GCC 4.4 and up works well with clang;
> however, it is not currently being used because Clang masks itself
> as GCC 4.2.1 for compatibility reasons. As Nick points out, we require
> GCC 4.6 and newer in the kernel so we can eliminate all of the
> versioning checks and just use the C version of umul_ppmm for all
> supported compilers.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/605
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> 
> This supersedes the following two patches:
> 
> https://lore.kernel.org/lkml/20190812033120.43013-4-natechancellor@gmail.com/
> 
> https://lore.kernel.org/lkml/20190812033120.43013-5-natechancellor@gmail.com/
> 
> I labelled this as a v2 so those don't get applied.
> 
>  lib/mpi/longlong.h | 36 +-----------------------------------
>  1 file changed, 1 insertion(+), 35 deletions(-)

Patch applied.  Thanks.

Patch
diff mbox series

diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
index 3bb6260d8f42..2dceaca27489 100644
--- a/lib/mpi/longlong.h
+++ b/lib/mpi/longlong.h
@@ -639,30 +639,12 @@  do { \
 	**************  MIPS  *****************
 	***************************************/
 #if defined(__mips__) && W_TYPE_SIZE == 32
-#if (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
 #define umul_ppmm(w1, w0, u, v)			\
 do {						\
 	UDItype __ll = (UDItype)(u) * (v);	\
 	w1 = __ll >> 32;			\
 	w0 = __ll;				\
 } while (0)
-#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7
-#define umul_ppmm(w1, w0, u, v) \
-	__asm__ ("multu %2,%3" \
-	: "=l" ((USItype)(w0)), \
-	     "=h" ((USItype)(w1)) \
-	: "d" ((USItype)(u)), \
-	     "d" ((USItype)(v)))
-#else
-#define umul_ppmm(w1, w0, u, v) \
-	__asm__ ("multu %2,%3\n" \
-	   "mflo %0\n" \
-	   "mfhi %1" \
-	: "=d" ((USItype)(w0)), \
-	     "=d" ((USItype)(w1)) \
-	: "d" ((USItype)(u)), \
-	     "d" ((USItype)(v)))
-#endif
 #define UMUL_TIME 10
 #define UDIV_TIME 100
 #endif /* __mips__ */
@@ -687,7 +669,7 @@  do {									\
 		 : "d" ((UDItype)(u)),					\
 		   "d" ((UDItype)(v)));					\
 } while (0)
-#elif (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
+#else
 #define umul_ppmm(w1, w0, u, v) \
 do {									\
 	typedef unsigned int __ll_UTItype __attribute__((mode(TI)));	\
@@ -695,22 +677,6 @@  do {									\
 	w1 = __ll >> 64;						\
 	w0 = __ll;							\
 } while (0)
-#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7
-#define umul_ppmm(w1, w0, u, v) \
-	__asm__ ("dmultu %2,%3" \
-	: "=l" ((UDItype)(w0)), \
-	     "=h" ((UDItype)(w1)) \
-	: "d" ((UDItype)(u)), \
-	     "d" ((UDItype)(v)))
-#else
-#define umul_ppmm(w1, w0, u, v) \
-	__asm__ ("dmultu %2,%3\n" \
-	   "mflo %0\n" \
-	   "mfhi %1" \
-	: "=d" ((UDItype)(w0)), \
-	     "=d" ((UDItype)(w1)) \
-	: "d" ((UDItype)(u)), \
-	     "d" ((UDItype)(v)))
 #endif
 #define UMUL_TIME 20
 #define UDIV_TIME 140