Re: PATCH RFC: Add pointer overflow warnings to 4.2 branch

[Mark Mitchell <mark at codesourcery dot com>]

Ian Lance Taylor wrote:
> Here is my proposed patch to add pointer overflow warnings to the 4.2
> branch.  The pointer wraparound code in 4.2 is different from 4.3 and
> mainline, and is somewhat simpler.
>
> Any comments on this patch?

> gcc/ChangeLog:
> 2008-05-02  Ian Lance Taylor  <iant@google.com>
>
> 	* flags.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Define.
> 	* fold-const.c (fold_overflow_warning): Remove assertion.
> 	(pointer_may_wrap_p): New static function.
> 	(fold_comparison): If appropriate, test
> 	POINTER_TYPE_OVERFLOW_UNDEFINED, and issue an overflow warning.
> 	(fold_binary): Test POINTER_TYPE_OVERFLOW_UNDEFINED when
> 	reassociating a pointer type.
> 	* doc/invoke.texi (Optimize Options): Document that
> 	-fstrict-overflow applies to pointer wraparound.
>
> gcc/testsuite/ChangeLog:
> 2008-05-02  Ian Lance Taylor  <iant@google.com>
>
> 	* gcc.dg/strict-overflow-6.c: New.
> 	* gcc.dg/no-strict-overflow-7.c: New.
> 	* gcc.dg/Wstrict-overflow-22.c: New.
> 	* gcc.c-torture/compile/20080419-1.c: New.
> 	* gcc.dg/tree-ssa/loop-17.c: Use -O2.

OK.

--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713