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[Bug target/37176] [arm] Optimizer omits loop condition leading to failing code
- From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 29 Aug 2008 05:33:34 -0000
- Subject: [Bug target/37176] [arm] Optimizer omits loop condition leading to failing code
- References: <bug-37176-16618@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #3 from pinskia at gcc dot gnu dot org 2008-08-29 05:33 -------
Oh I see the issue, it is due to the way prefetch is defined. It is defined
incorrectly. The asm does basically:
char a = *(char*)possible_NULL_POINTER;
if (!possible_NULL_POINTER)
break;
Now this is really valid for the compiler to assume (I never got this point to
Ian who did the fix for it). Anyways GCC behavior was changed back with:
2008-07-23 Ian Lance Taylor <iant@google.com>
* tree-vrp.c (infer_value_range): Ignore asm statements when
looking for memory accesses for -fdelete-null-pointer-checks.
Anyways you should be using __builtin_prefetch instead.
Which was in 4.3.2.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.3.2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37176