Re: [PATCH] Fix PR83089

[Richard Biener <rguenther@suse.de>]

On Wed, 22 Nov 2017, Christophe Lyon wrote:

> 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?

From some specs processing I guess.  Didn't think that it could
happen for a compile only testcase.

Fixed with

2017-11-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83089
	* gcc.dg/pr83089.c: Require pthread.

Index: gcc/testsuite/gcc.dg/pr83089.c
===================================================================
--- gcc/testsuite/gcc.dg/pr83089.c	(revision 255060)
+++ gcc/testsuite/gcc.dg/pr83089.c	(working copy)
@@ -1,4 +1,5 @@
 /* { dg-do compile } */
+/* { dg-require-effective-target pthread } */
 /* { dg-options "-O2 -ftree-loop-if-convert -ftree-parallelize-loops=2" } */
 
 int rl, s8;