[PATCH] target/ppc: fix unreachable code in fpu_helper.c

[PATCH] target/ppc: fix unreachable code in fpu_helper.c

[Daniel Henrique Barboza]

Commit c29018cc7395 added an env->fpscr OR operation using a ternary
that checks if 'error' is not zero:

    env->fpscr |= error ? FP_FEX : 0;

However, in the current body of do_fpscr_check_status(), 'error' is
granted to be always non-zero at that point. The result is that Coverity
is less than pleased:

  Control flow issues  (DEADCODE)
Execution cannot reach the expression "0ULL" inside this statement:
"env->fpscr |= (error ? 1073...".

Remove the ternary and always make env->fpscr |= FP_FEX.

Cc: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Cc: Richard Henderson <richard.henderson@linaro.org>
Fixes: Coverity CID 1489442
Fixes: c29018cc7395 ("target/ppc: Implemented xvf*ger*")
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/fpu_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index fed0ce420a..7ab6beadad 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -464,7 +464,7 @@ static void do_fpscr_check_status(CPUPPCState *env, uintptr_t raddr)
     }
     cs->exception_index = POWERPC_EXCP_PROGRAM;
     env->error_code = error | POWERPC_EXCP_FP;
-    env->fpscr |= error ? FP_FEX : 0;
+    env->fpscr |= FP_FEX;
     /* Deferred floating-point exception after target FPSCR update */
     if (fp_exceptions_enabled(env)) {
         raise_exception_err_ra(env, cs->exception_index,
-- 
2.36.1

Re: [PATCH] target/ppc: fix unreachable code in fpu_helper.c

[Lucas Mateus Martins Araujo e Castro]

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On 02/06/2022 16:10, Daniel Henrique Barboza wrote:
> Commit c29018cc7395 added an env->fpscr OR operation using a ternary
> that checks if 'error' is not zero:
>
>      env->fpscr |= error ? FP_FEX : 0;
>
> However, in the current body of do_fpscr_check_status(), 'error' is
> granted to be always non-zero at that point. The result is that Coverity
> is less than pleased:
>
>    Control flow issues  (DEADCODE)
> Execution cannot reach the expression "0ULL" inside this statement:
> "env->fpscr |= (error ? 1073...".
>
> Remove the ternary and always make env->fpscr |= FP_FEX.
>
> Cc: Lucas Mateus Castro (alqotel)<lucas.araujo@eldorado.org.br>
> Cc: Richard Henderson<richard.henderson@linaro.org>
> Fixes: Coverity CID 1489442
> Fixes: c29018cc7395 ("target/ppc: Implemented xvf*ger*")
> Signed-off-by: Daniel Henrique Barboza<danielhb413@gmail.com>
> ---
>
Reviewed-by: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
-- 
Lucas Mateus M. Araujo e Castro
Instituto de Pesquisas ELDORADO 
<https://www.eldorado.org.br/?utm_campaign=assinatura_de_e-mail&utm_medium=email&utm_source=RD+Station>
Departamento Computação Embarcada
Analista de Software Trainee
Aviso Legal - Disclaimer <https://www.eldorado.org.br/disclaimer.html>

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Re: [PATCH] target/ppc: fix unreachable code in fpu_helper.c

[Daniel Henrique Barboza]

Queued in gitlab.com/danielhb/qemu/tree/ppc-next. Thanks,


Daniel

On 6/2/22 16:10, Daniel Henrique Barboza wrote:
> Commit c29018cc7395 added an env->fpscr OR operation using a ternary
> that checks if 'error' is not zero:
> 
>      env->fpscr |= error ? FP_FEX : 0;
> 
> However, in the current body of do_fpscr_check_status(), 'error' is
> granted to be always non-zero at that point. The result is that Coverity
> is less than pleased:
> 
>    Control flow issues  (DEADCODE)
> Execution cannot reach the expression "0ULL" inside this statement:
> "env->fpscr |= (error ? 1073...".
> 
> Remove the ternary and always make env->fpscr |= FP_FEX.
> 
> Cc: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Fixes: Coverity CID 1489442
> Fixes: c29018cc7395 ("target/ppc: Implemented xvf*ger*")
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
>   target/ppc/fpu_helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
> index fed0ce420a..7ab6beadad 100644
> --- a/target/ppc/fpu_helper.c
> +++ b/target/ppc/fpu_helper.c
> @@ -464,7 +464,7 @@ static void do_fpscr_check_status(CPUPPCState *env, uintptr_t raddr)
>       }
>       cs->exception_index = POWERPC_EXCP_PROGRAM;
>       env->error_code = error | POWERPC_EXCP_FP;
> -    env->fpscr |= error ? FP_FEX : 0;
> +    env->fpscr |= FP_FEX;
>       /* Deferred floating-point exception after target FPSCR update */
>       if (fp_exceptions_enabled(env)) {
>           raise_exception_err_ra(env, cs->exception_index,