| Message ID | 20200813073712.4001404-9-kuhn.chenqun@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | trivial patchs for static code analyzer fixes | expand |
On 8/13/20 12:37 AM, Chen Qun wrote: > Clang static code analyzer show warning: > tcg/optimize.c:1267:17: warning: Value stored to 'nb_iargs' is never read > nb_iargs = 2; > ^ ~ > > Reported-by: Euler Robot <euler.robot@huawei.com> > Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com> > --- > Cc: Richard Henderson <richard.henderson@linaro.org> > Cc: Richard Henderson <rth@twiddle.net> > --- > tcg/optimize.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/tcg/optimize.c b/tcg/optimize.c > index 53aa8e5329..d5bea37290 100644 > --- a/tcg/optimize.c > +++ b/tcg/optimize.c > @@ -1264,7 +1264,6 @@ void tcg_optimize(TCGContext *s) > op->opc = opc = (opc == INDEX_op_movcond_i32 > ? INDEX_op_setcond_i32 > : INDEX_op_setcond_i64); > - nb_iargs = 2; > } > goto do_default; I prefer not to make this change. nb_iargs is the cached value that corresponds to opc, which we have just changed. If we later make a change at "do_default" that uses nb_iargs, failure to update the value here will be a very hard bug to find. I am happy to let the compiler remove this as dead code itself. r~
> > diff --git a/tcg/optimize.c b/tcg/optimize.c index > > 53aa8e5329..d5bea37290 100644 > > --- a/tcg/optimize.c > > +++ b/tcg/optimize.c > > @@ -1264,7 +1264,6 @@ void tcg_optimize(TCGContext *s) > > op->opc = opc = (opc == INDEX_op_movcond_i32 > > ? INDEX_op_setcond_i32 > > : INDEX_op_setcond_i64); > > - nb_iargs = 2; > > } > > goto do_default; > > I prefer not to make this change. > > nb_iargs is the cached value that corresponds to opc, which we have just > changed. If we later make a change at "do_default" that uses nb_iargs, > failure to update the value here will be a very hard bug to find. Hi Richard, I think you're thinking more carefully, even though ' nb_iargs' not used in 'do_default' now. However, I have only one small question. Why does 'nb_iargs' need to be assigned a value for this case branch? Other branches(eg:' CASE_OP_32_64(brcond)') have changed the opc value too. Do we need to assign a value to nb_iargs for it? Thanks.
On 8/17/20 6:04 AM, Chenqun (kuhn) wrote:
> Other branches(eg:' CASE_OP_32_64(brcond)') have changed the opc value too. Do we need to assign a value to nb_iargs for it?
In those cases nb_iargs does not change.
r~
diff --git a/tcg/optimize.c b/tcg/optimize.c index 53aa8e5329..d5bea37290 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -1264,7 +1264,6 @@ void tcg_optimize(TCGContext *s) op->opc = opc = (opc == INDEX_op_movcond_i32 ? INDEX_op_setcond_i32 : INDEX_op_setcond_i64); - nb_iargs = 2; } goto do_default;
Clang static code analyzer show warning: tcg/optimize.c:1267:17: warning: Value stored to 'nb_iargs' is never read nb_iargs = 2; ^ ~ Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com> --- Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Richard Henderson <rth@twiddle.net> --- tcg/optimize.c | 1 - 1 file changed, 1 deletion(-)