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Re: [ping] Re: [Patch, libgcc] Fix build warnings in fixed-bit.c
On 15 Jun 2012, at 14:31, Iain Sandoe wrote:
> When building for, say, mips-linux-gnu, the build of objects from fixed-bit.c produces a lot of "set but not used" warnings for min_high & min_low.
>
> looking at the code, these appear to be genuine.
> Fixed as below.
>
> OK for trunk?
> Iain
>
> libgcc:
> * fixed-bit.c (SATFRACT): Adjust declarations and init for
> min_high, min_low.
>
>
> Index: libgcc/fixed-bit.c
> ===================================================================
> --- libgcc/fixed-bit.c (revision 188657)
> +++ libgcc/fixed-bit.c (working copy)
> @@ -768,11 +768,12 @@ SATFRACT (FROM_FIXED_C_TYPE a)
> #if FROM_MODE_UNSIGNED == 0
> BIG_SINT_C_TYPE high, low;
> BIG_SINT_C_TYPE max_high, max_low;
> +# if TO_MODE_UNSIGNED == 0
> BIG_SINT_C_TYPE min_high, min_low;
> +# endif
> #else
> BIG_UINT_C_TYPE high, low;
> BIG_UINT_C_TYPE max_high, max_low;
> - BIG_UINT_C_TYPE min_high, min_low;
> #endif
> #if TO_FBITS > FROM_FBITS
> BIG_UINT_C_TYPE utemp;
> @@ -819,13 +820,12 @@ SATFRACT (FROM_FIXED_C_TYPE a)
> #endif
>
> #if TO_MODE_UNSIGNED == 0
> - min_high = -1;
> stemp = (BIG_SINT_C_TYPE)1 << (BIG_WIDTH - 1);
> stemp = stemp >> (BIG_WIDTH - 1 - TO_I_F_BITS);
> +# if FROM_MODE_UNSIGNED == 0
> + min_high = -1;
> min_low = stemp;
> -#else
> - min_high = 0;
> - min_low = 0;
> +# endif
> #endif
As far as I can see, there is no need to move the min_high line. You
should just move the four lines from the setting of min_high to the
setting of min_low into the
#if FROM_MODE_UNSIGNED == 0 && TO_MODE_UNSIGNED == 0
section just below. For simplicity you should move the declarations of
min_high, min_low, and stemp into a section with the same #if.
> #if FROM_MODE_UNSIGNED == 0 && TO_MODE_UNSIGNED == 0
> @@ -973,9 +973,9 @@ SATFRACT (FROM_INT_C_TYPE a)
> FROM_INT_C_TYPE x = a;
> BIG_SINT_C_TYPE high, low;
> BIG_SINT_C_TYPE max_high, max_low;
> - BIG_SINT_C_TYPE min_high, min_low;
> #if TO_MODE_UNSIGNED == 0
> BIG_SINT_C_TYPE stemp;
> + BIG_SINT_C_TYPE min_low, min_high;
> #endif
> #if BIG_WIDTH != TO_FBITS
> BIG_UINT_C_TYPE utemp;
> @@ -1011,13 +1011,10 @@ SATFRACT (FROM_INT_C_TYPE a)
> #endif
>
> #if TO_MODE_UNSIGNED == 0
> - min_high = -1;
> stemp = (BIG_SINT_C_TYPE)1 << (BIG_WIDTH - 1);
> stemp = stemp >> (BIG_WIDTH - 1 - TO_I_F_BITS);
> min_low = stemp;
> -#else
> - min_high = 0;
> - min_low = 0;
> + min_high = -1;
> #endif
Don't move the assignment to min_high, just drop the #else part.
Ian