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From: Nathan Chancellor <nathan@kernel.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 2/2] powerpc/math-emu: Remove -w build flag and fix warnings
Date: Fri, 2 Sep 2022 08:37:23 -0700	[thread overview]
Message-ID: <YxIjM/jdLajq4dFk@dev-arch.thelio-3990X> (raw)
In-Reply-To: <35c86b7ca823954c6cd593acc3690dc3748da9b1.1662113301.git.christophe.leroy@csgroup.eu>

Hi Christophe,

On Fri, Sep 02, 2022 at 12:08:55PM +0200, Christophe Leroy wrote:
> As reported by Nathan, the module_init() macro was not taken into
> account because the header was missing. That means spe_mathemu_init()
> was never called.
> 
> This should have been detected by gcc at build time, but due to
> '-w' flag it went undetected.
> 
> Removing that flag leads to many warnings hence errors.
> 
> Fix those warnings then remove the -w flag.
> 
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

Thanks for figuring out what was going on here! I took this patch for a
spin with clang and it has a few more errors around
-Wimplicit-fallthrough:

    arch/powerpc/math-emu/fctiw.c:18:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
            FP_TO_INT_D(r, B, 32, 1);
            ^
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/fctiw.c:18:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    2 errors generated.
    arch/powerpc/math-emu/fctiwz.c:23:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
            FP_TO_INT_D(r, B, 32, 1);
            ^
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/fctiwz.c:23:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    2 errors generated.
    make[3]: *** [scripts/Makefile.build:249: arch/powerpc/math-emu/fctiw.o] Error 1
    make[3]: *** [scripts/Makefile.build:249: arch/powerpc/math-emu/fctiwz.o] Error 1
    arch/powerpc/math-emu/math_efp.c:282:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[1], SB, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:305:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[1], SB, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:316:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_S(vc.wp[1], SB, 32,
                                    ^
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/math_efp.c:316:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:413:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_D(vc.wp[1], DB, 32,
                                    ^
    ./include/math-emu/double.h:121:40: note: expanded from macro 'FP_TO_INT_ROUND_D'
    #define FP_TO_INT_ROUND_D(r,X,rsz,rsg)  _FP_TO_INT_ROUND(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:436:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_D(vc.dp[0], DB, 64,
                                    ^
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/math_efp.c:436:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:447:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_D(vc.wp[1], DB, 32,
                                    ^
    ./include/math-emu/double.h:121:40: note: expanded from macro 'FP_TO_INT_ROUND_D'
    #define FP_TO_INT_ROUND_D(r,X,rsz,rsg)  _FP_TO_INT_ROUND(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:458:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_D(vc.wp[1], DB, 32,
                                    ^
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/math_efp.c:458:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/double.h:120:34: note: expanded from macro 'FP_TO_INT_D'
    #define FP_TO_INT_D(r,X,rsz,rsg)        _FP_TO_INT(D,2,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:573:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[0], SB0, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:581:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[1], SB1, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:592:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[0], SB0, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:599:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_ROUND_S(vc.wp[1], SB1, 32,
                                    ^
    ./include/math-emu/single.h:110:40: note: expanded from macro 'FP_TO_INT_ROUND_S'
    #define FP_TO_INT_ROUND_S(r,X,rsz,rsg)  _FP_TO_INT_ROUND(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:770:4: note: expanded from macro '_FP_TO_INT_ROUND'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:610:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_S(vc.wp[0], SB0, 32,
                                    ^
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/math_efp.c:610:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    arch/powerpc/math-emu/math_efp.c:617:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
                                    FP_TO_INT_S(vc.wp[1], SB1, 32,
                                    ^
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:665:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_ZERO:                                                     \
              ^
    arch/powerpc/math-emu/math_efp.c:617:5: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
    ./include/math-emu/single.h:109:34: note: expanded from macro 'FP_TO_INT_S'
    #define FP_TO_INT_S(r,X,rsz,rsg)        _FP_TO_INT(S,1,r,X,rsz,rsg)
                                            ^
    ./include/math-emu/op-common.h:671:4: note: expanded from macro '_FP_TO_INT'
              case FP_CLS_NAN:                                                      \
              ^
    18 errors generated.

The following diff resolves it and does not introduce any new issues
with GCC. Would you mind squashing it in for a v2? With that:

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Cheers,
Nathan

diff --git a/include/math-emu/op-common.h b/include/math-emu/op-common.h
index 4b57bbba588a..ae73a30bf1a0 100644
--- a/include/math-emu/op-common.h
+++ b/include/math-emu/op-common.h
@@ -662,12 +662,14 @@ do {									\
 	if (X##_e < 0)								\
 	  {									\
 	    FP_SET_EXCEPTION(FP_EX_INEXACT);					\
+	    fallthrough;							\
 	  case FP_CLS_ZERO:							\
 	    r = 0;								\
 	  }									\
 	else if (X##_e >= rsize - (rsigned > 0 || X##_s)			\
 		 || (!rsigned && X##_s))					\
 	  {	/* overflow */							\
+	  fallthrough;								\
 	  case FP_CLS_NAN:                                                      \
 	  case FP_CLS_INF:							\
 	    if (rsigned == 2)							\
@@ -767,6 +769,7 @@ do {									\
 	if (X##_e >= rsize - (rsigned > 0 || X##_s)				\
 	    || (!rsigned && X##_s))						\
 	  {	/* overflow */							\
+	  fallthrough;								\
 	  case FP_CLS_NAN:                                                      \
 	  case FP_CLS_INF:							\
 	    if (!rsigned)							\

  reply	other threads:[~2022-09-02 15:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-02 10:08 [PATCH v2 1/2] powerpc/math_emu/efp: Include module.h Christophe Leroy
2022-09-02 10:08 ` [PATCH v2 2/2] powerpc/math-emu: Remove -w build flag and fix warnings Christophe Leroy
2022-09-02 15:37   ` Nathan Chancellor [this message]
2022-09-02 15:59     ` Segher Boessenkool
2022-09-02 16:11       ` Christophe Leroy
2022-09-02 16:11       ` Nathan Chancellor
2022-09-02 16:27         ` Segher Boessenkool
2022-09-02 16:00 [PATCH v2 1/2] powerpc/math_emu/efp: Include module.h Christophe Leroy
2022-09-02 16:00 ` [PATCH v2 2/2] powerpc/math-emu: Remove -w build flag and fix warnings Christophe Leroy

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