[PATCH] Fix simplify_const_unary_operation (PR debug/48204)

[Richard Guenther]

On Wed, Mar 23, 2011 at 9:11 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> simplify_const_unary_operation assumes it doesn't have to change anything
> in REAL_VALUE_TYPE for FLOAT_EXTEND, which is wrong when FLOAT_EXTENDing
> e.g. from SFmode to DDmode or SDmode to DFmode, where the number
> needs to be converted from binary to decimal or vice versa.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk/4.6.1?

Ok.

Thanks,
Richard.

> 2011-03-23  Jakub Jelinek  <jakub@redhat.com>
>
>        PR debug/48204
>        * simplify-rtx.c (simplify_const_unary_operation): Call
>        real_convert when changing mode class with FLOAT_EXTEND.
>
>        * gcc.dg/dfp/pr48204.c: New test.
>
> --- gcc/simplify-rtx.c.jj       2011-03-21 13:00:09.000000000 +0100
> +++ gcc/simplify-rtx.c  2011-03-23 16:39:13.000000000 +0100
> @@ -1526,7 +1526,8 @@ simplify_const_unary_operation (enum rtx
>     }
>
>   else if (GET_CODE (op) == CONST_DOUBLE
> -          && SCALAR_FLOAT_MODE_P (mode))
> +          && SCALAR_FLOAT_MODE_P (mode)
> +          && SCALAR_FLOAT_MODE_P (GET_MODE (op)))
>     {
>       REAL_VALUE_TYPE d, t;
>       REAL_VALUE_FROM_CONST_DOUBLE (d, op);
> @@ -1549,7 +1550,10 @@ simplify_const_unary_operation (enum rtx
>          d = real_value_truncate (mode, d);
>          break;
>        case FLOAT_EXTEND:
> -         /* All this does is change the mode.  */
> +         /* All this does is change the mode, unless changing
> +            mode class.  */
> +         if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (op)))
> +           real_convert (&d, mode, &d);
>          break;
>        case FIX:
>          real_arithmetic (&d, FIX_TRUNC_EXPR, &d, NULL);
> --- gcc/testsuite/gcc.dg/dfp/pr48204.c.jj       2011-03-23 16:44:09.000000000 +0100
> +++ gcc/testsuite/gcc.dg/dfp/pr48204.c  2011-03-23 16:43:35.000000000 +0100
> @@ -0,0 +1,10 @@
> +/* PR debug/48204 */
> +/* { dg-do compile } */
> +/* { dg-options "-O -fno-tree-ccp -fno-tree-dominator-opts -fno-tree-fre -g" } */
> +
> +void
> +foo (void)
> +{
> +  float cf = 3.0f;
> +  _Decimal64 d64 = cf;
> +}
>
>        Jakub
>