Re: [PATCH] Fix PR83089

[Christophe Lyon <christophe.lyon@linaro.org>]

On 22 November 2017 at 09:44, Richard Biener <rguenther@suse.de> wrote:
>
> The following fixes if-conversion to free SCEV/niter estimates because
> it DCEs stmts.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
>
> Richard.
>
> 2017-11-22  Richard Biener  <rguenther@suse.de>
>
>         PR tree-optimization/83089
>         * tree-if-conv.c (pass_if_conversion::execute): If anything
>         changed reset SCEV and free the number of iteration estimates.
>
>         * gcc.dg/pr83089.c: New testcase.
>
> Index: gcc/tree-if-conv.c
> ===================================================================
> --- gcc/tree-if-conv.c  (revision 254990)
> +++ gcc/tree-if-conv.c  (working copy)
> @@ -2959,6 +2959,12 @@ pass_if_conversion::execute (function *f
>             && !loop->dont_vectorize))
>        todo |= tree_if_conversion (loop);
>
> +  if (todo)
> +    {
> +      free_numbers_of_iterations_estimates (fun);
> +      scev_reset ();
> +    }
> +
>    if (flag_checking)
>      {
>        basic_block bb;
> Index: gcc/testsuite/gcc.dg/pr83089.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/pr83089.c      (nonexistent)
> +++ gcc/testsuite/gcc.dg/pr83089.c      (working copy)
> @@ -0,0 +1,27 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -ftree-loop-if-convert -ftree-parallelize-loops=2" } */
> +
> +int rl, s8;
> +
> +void
> +it (int zy, short int el)
> +{
> +  int hb;
> +
> +  while (el != 0)
> +    {
> +      hb = el;
> +      for (rl = 0; rl < 200; ++rl)
> +       {
> +         for (s8 = 0; s8 < 2; ++s8)
> +           {
> +           }
> +         if (s8 < 3)
> +           zy = hb;
> +         if (hb == 0)
> +           ++s8;
> +         zy += (s8 != -1);
> +       }
> +      el = zy;
> +    }
> +}

I see the new testcase failing to compile on bare-metal targets
(aarch64-elf, arm-eabi):
spawn -ignore SIGHUP
/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-aarch64-none-elf/gcc3/gcc/xgcc
-B/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-aarch64-none-elf/gcc3/gcc/
/gcc/testsuite/gcc.dg/pr83089.c -fno-diagnostics-show-caret
-fdiagnostics-color=never -O2 -ftree-loop-if-convert
-ftree-parallelize-loops=2 -S -specs=aem-ve.specs -o pr83089.s
xgcc: error: unrecognized command line option '-pthread'
compiler exited with status 1
FAIL: gcc.dg/pr83089.c (test for excess errors)

Where does that -pthread come from?