On Wed, 13 Dec 2017, Jakub Jelinek wrote:
> Hi!
>
> This patch fixes 2 issues in format_floating. One is that when determining
> precision, we should consider solely the type *printf* will read the
> argument as (i.e. double unless L or ll modifier is used, in which case
> long double), not the type of the argument, because the corresponding
> argument could have any type, even not floating, or say __float128 etc.
>
> This is fixed in the first 2 hunks.
>
> The last hunk is to treat REAL_CSTs arguments of incompatible types
> as unknown argument, we really don't know what say __float128 passed to
> %f or double passed to %La will do; that is something diagnosed by -Wformat,
> so the patch just treats it as arbitrary value of the type.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Richard.
> 2017-12-13 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/83198
> * gimple-ssa-sprintf.c (format_floating): Set type solely based on
> dir.modifier, regardless of TREE_TYPE (arg). Assume non-REAL_CST
> value if arg is a REAL_CST with incompatible type.
>
> * gcc.dg/pr83198.c: New test.
>
> --- gcc/gimple-ssa-sprintf.c.jj 2017-11-03 15:37:04.000000000 +0100
> +++ gcc/gimple-ssa-sprintf.c 2017-12-13 13:37:59.289435623 +0100
> @@ -1885,6 +1885,8 @@ static fmtresult
> format_floating (const directive &dir, tree arg)
> {
> HOST_WIDE_INT prec[] = { dir.prec[0], dir.prec[1] };
> + tree type = (dir.modifier == FMT_LEN_L || dir.modifier == FMT_LEN_ll
> + ? long_double_type_node : double_type_node);
>
> /* For an indeterminate precision the lower bound must be assumed
> to be zero. */
> @@ -1892,10 +1894,6 @@ format_floating (const directive &dir, t
> {
> /* Get the number of fractional decimal digits needed to represent
> the argument without a loss of accuracy. */
> - tree type = arg ? TREE_TYPE (arg) :
> - (dir.modifier == FMT_LEN_L || dir.modifier == FMT_LEN_ll
> - ? long_double_type_node : double_type_node);
> -
> unsigned fmtprec
> = REAL_MODE_FORMAT (TYPE_MODE (type))->p;
>
> @@ -1946,7 +1944,9 @@ format_floating (const directive &dir, t
> }
> }
>
> - if (!arg || TREE_CODE (arg) != REAL_CST)
> + if (!arg
> + || TREE_CODE (arg) != REAL_CST
> + || !useless_type_conversion_p (type, TREE_TYPE (arg)))
> return format_floating (dir, prec);
>
> /* The minimum and maximum number of bytes produced by the directive. */
> --- gcc/testsuite/gcc.dg/pr83198.c.jj 2017-12-13 13:43:36.056192309 +0100
> +++ gcc/testsuite/gcc.dg/pr83198.c 2017-12-13 13:47:11.716474956 +0100
> @@ -0,0 +1,18 @@
> +/* PR tree-optimization/83198 */
> +/* { dg-do compile } */
> +/* { dg-options "-Wall -Wno-format" } */
> +
> +int
> +foo (char *d[6], int x)
> +{
> + int r = 0;
> + r += __builtin_sprintf (d[0], "%f", x);
> + r += __builtin_sprintf (d[1], "%a", x);
> + r += __builtin_sprintf (d[2], "%f", "foo");
> + r += __builtin_sprintf (d[3], "%a", "bar");
> +#ifdef __SIZEOF_FLOAT128__
> + r += __builtin_sprintf (d[4], "%a", 1.0Q);
> + r += __builtin_sprintf (d[5], "%Lf", 1.0Q);
> +#endif
> + return r;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
