On Tue, Apr 19, 2016 at 8:35 PM, Marek Polacek <pola...@redhat.com> wrote:
> While predicate_mem_writes has a check to skip conditions that were evaluated
> to true, it's lacking the same check for false, so we hit an assert later on.
> So I'm adding is_false_predicate. Maybe it should be added to other spots as
> well, but I'm not sure about that.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2016-04-19 Marek Polacek <pola...@redhat.com>
>
> PR tree-optimization/70725
> * tree-if-conv.c (is_false_predicate): New function.
> (predicate_mem_writes): Use it.
>
> * gcc.dg/pr70725.c: New test.
>
> diff --git gcc/testsuite/gcc.dg/pr70725.c gcc/testsuite/gcc.dg/pr70725.c
> index e69de29..fc7b674 100644
> --- gcc/testsuite/gcc.dg/pr70725.c
> +++ gcc/testsuite/gcc.dg/pr70725.c
> @@ -0,0 +1,22 @@
> +/* PR tree-optimization/70725 */
> +/* { dg-do compile } */
> +/* { dg-options "-O3" } */
> +/* { dg-additional-options "-march=skylake-avx512" { target { i?86-*-*
> x86_64-*-* } } } */
> +
> +extern short a;
> +extern int b, d;
> +extern int c[100];
> +extern int e;
> +extern int f;
> +
> +void
> +fn1 ()
> +{
> + for (; e < 2; e = e + 1)
> + d = a;
> + for (;;)
> + for (int g = 0; g < 5; g = g + 1)
> + for (int h = 0; h < 2; h = h + 1)
> + for (int i = 0; i < 3; i = i + 1)
> + c[f + i] = a && b;
> +}
> diff --git gcc/tree-if-conv.c gcc/tree-if-conv.c
> index 9e305c7..a9fbab9 100644
> --- gcc/tree-if-conv.c
> +++ gcc/tree-if-conv.c
> @@ -262,6 +262,16 @@ ifc_temp_var (tree type, tree expr, gimple_stmt_iterator
> *gsi)
> return new_name;
> }
>
> +/* Return true when COND is a false predicate. */
> +
> +static inline bool
> +is_false_predicate (tree cond)
> +{
> + return (cond == NULL_TREE
> + || cond == boolean_false_node
> + || integer_zerop (cond));
> +}
> +
> /* Return true when COND is a true predicate. */
>
> static inline bool
> @@ -1988,7 +1998,7 @@ predicate_mem_writes (loop_p loop)
> gimple *stmt;
> int index;
>
> - if (is_true_predicate (cond))
> + if (is_true_predicate (cond) || is_false_predicate (cond))
> continue;
>
> swap = false;
>
> Marek
