[PATCH] Fix recip opt ICEs with -fnon-call-exceptions (PR tree-optimization/90090)

[Richard Biener]

On Tue, 16 Apr 2019, Jakub Jelinek wrote:

> Hi!
> 
> While we in theory could move over the EH stuff from the division
> instructions to the multiplication ones (right now we do not do even that),
> we would need to add EH even to the divisions added by insert_reciprocals.
> 
> The following patch just punts on divisions that can throw internally,
> bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK.

Richard.

> If it affects some important -fnon-call-exceptions codebase and anyone is
> interested in handling it differently, it can be always reverted and handled
> properly.
> 
> 2019-04-16  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR tree-optimization/90090
> 	* tree-ssa-math-opts.c (is_division_by): Ignore divisions that can
> 	throw internally.
> 	(is_division_by_square): Likewise.  Formatting fix.
> 
> 	* g++.dg/opt/pr90090.C: New test.
> 
> --- gcc/tree-ssa-math-opts.c.jj	2019-04-08 10:11:28.620219138 +0200
> +++ gcc/tree-ssa-math-opts.c	2019-04-15 09:42:22.173868303 +0200
> @@ -334,7 +334,8 @@ is_division_by (gimple *use_stmt, tree d
>  	 /* Do not recognize x / x as valid division, as we are getting
>  	    confused later by replacing all immediate uses x in such
>  	    a stmt.  */
> -	 && gimple_assign_rhs1 (use_stmt) != def;
> +	 && gimple_assign_rhs1 (use_stmt) != def
> +	 && !stmt_can_throw_internal (cfun, use_stmt);
>  }
>  
>  /* Return TRUE if USE_STMT is a multiplication of DEF by A.  */
> @@ -367,13 +368,12 @@ is_division_by_square (gimple *use_stmt,
>  {
>    if (gimple_code (use_stmt) == GIMPLE_ASSIGN
>        && gimple_assign_rhs_code (use_stmt) == RDIV_EXPR
> -      && gimple_assign_rhs1 (use_stmt) != gimple_assign_rhs2 (use_stmt))
> +      && gimple_assign_rhs1 (use_stmt) != gimple_assign_rhs2 (use_stmt)
> +      && !stmt_can_throw_internal (cfun, use_stmt))
>      {
>        tree denominator = gimple_assign_rhs2 (use_stmt);
>        if (TREE_CODE (denominator) == SSA_NAME)
> -	{
> -	  return is_square_of (SSA_NAME_DEF_STMT (denominator), def);
> -	}
> +	return is_square_of (SSA_NAME_DEF_STMT (denominator), def);
>      }
>    return 0;
>  }
> --- gcc/testsuite/g++.dg/opt/pr90090.C.jj	2019-04-15 10:34:58.151821097 +0200
> +++ gcc/testsuite/g++.dg/opt/pr90090.C	2019-04-15 10:36:12.856620867 +0200
> @@ -0,0 +1,19 @@
> +// PR tree-optimization/90090
> +// { dg-do compile }
> +// { dg-options "-Ofast -fno-associative-math -fsignaling-nans -fno-tree-dce -fnon-call-exceptions" }
> +
> +double bar (double, double, double, double, double);
> +double baz ();
> +
> +double
> +foo (double a)
> +{
> +  try
> +    {
> +      return bar (1.0/a, 2.0/a, 4.0/a, 8.0/a, 16.0/a);
> +    }
> +  catch (...)
> +    {
> +      return baz ();
> +    }
> +}
> 
> 	Jakub
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
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