Temporarily handle COMPOUND_EXPR in convert_* (PR c++/56493)

Hi!

As discussed in the PR, ideally this should be done in the middle-end,
but no fix materialized for it during the last 18 months and is unlikely
to happen for GCC 5 either, so this patch just restores what the FEs used
to produce.  Bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2014-12-03  Jakub Jelinek  <jakub@redhat.com>

	PR c++/56493
	* convert.c (convert_to_real, convert_to_expr, convert_to_complex):
	Handle COMPOUND_EXPR.

	* c-c++-common/pr56493.c: New test.


	Jakub

On Wed, 3 Dec 2014, Jakub Jelinek wrote:

> Hi!
> 
> As discussed in the PR, ideally this should be done in the middle-end,
> but no fix materialized for it during the last 18 months and is unlikely
> to happen for GCC 5 either, so this patch just restores what the FEs used
> to produce.  Bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?

Ok.  Might want to backport this as well.

Thanks,
Richard.

> 2014-12-03  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR c++/56493
> 	* convert.c (convert_to_real, convert_to_expr, convert_to_complex):
> 	Handle COMPOUND_EXPR.
> 
> 	* c-c++-common/pr56493.c: New test.
> 
> --- gcc/convert.c.jj	2014-11-11 00:06:25.016769050 +0100
> +++ gcc/convert.c	2014-12-03 11:22:16.193539558 +0100
> @@ -99,6 +99,15 @@ convert_to_real (tree type, tree expr)
>    enum built_in_function fcode = builtin_mathfn_code (expr);
>    tree itype = TREE_TYPE (expr);
>  
> +  if (TREE_CODE (expr) == COMPOUND_EXPR)
> +    {
> +      tree t = convert_to_real (type, TREE_OPERAND (expr, 1));
> +      if (t == TREE_OPERAND (expr, 1))
> +	return expr;
> +      return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (t),
> +			 TREE_OPERAND (expr, 0), t);
> +    }    
> +
>    /* Disable until we figure out how to decide whether the functions are
>       present in runtime.  */
>    /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
> @@ -406,6 +415,15 @@ convert_to_integer (tree type, tree expr
>        return error_mark_node;
>      }
>  
> +  if (ex_form == COMPOUND_EXPR)
> +    {
> +      tree t = convert_to_integer (type, TREE_OPERAND (expr, 1));
> +      if (t == TREE_OPERAND (expr, 1))
> +	return expr;
> +      return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (t),
> +			 TREE_OPERAND (expr, 0), t);
> +    }    
> +
>    /* Convert e.g. (long)round(d) -> lround(d).  */
>    /* If we're converting to char, we may encounter differing behavior
>       between converting from double->char vs double->long->char.
> @@ -926,6 +944,14 @@ convert_to_complex (tree type, tree expr
>  
>  	if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
>  	  return expr;
> +	else if (TREE_CODE (expr) == COMPOUND_EXPR)
> +	  {
> +	    tree t = convert_to_complex (type, TREE_OPERAND (expr, 1));
> +	    if (t == TREE_OPERAND (expr, 1))
> +	      return expr;
> +	    return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR,
> +			       TREE_TYPE (t), TREE_OPERAND (expr, 0), t);
> +	  }    
>  	else if (TREE_CODE (expr) == COMPLEX_EXPR)
>  	  return fold_build2 (COMPLEX_EXPR, type,
>  			      convert (subtype, TREE_OPERAND (expr, 0)),
> --- gcc/testsuite/c-c++-common/pr56493.c.jj	2014-12-03 11:22:16.193539558 +0100
> +++ gcc/testsuite/c-c++-common/pr56493.c	2014-12-03 11:22:16.193539558 +0100
> @@ -0,0 +1,16 @@
> +/* PR c++/56493 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-gimple" } */
> +
> +unsigned long long bar (void);
> +int x;
> +
> +void
> +foo (void)
> +{
> +  x += bar ();
> +}
> +
> +/* Verify we narrow the addition from unsigned long long to unsigned int type.  */
> +/* { dg-final { scan-tree-dump "  (\[a-zA-Z._0-9]*) = \\(unsigned int\\) \[^;\n\r]*;.*  (\[a-zA-Z._0-9]*) = \\(unsigned int\\) \[^;\n\r]*;.* = \\1 \\+ \\2;" "gimple" { target { ilp32 || lp64 } } } } */
> +/* { dg-final { cleanup-tree-dump "gimple" } } */
> 
> 	Jakub
> 
>