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[Bug tree-optimization/32328] [4.2/4.3 Regression] -fstrict-aliasing causes skipped code
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Jul 2007 15:51:44 -0000
- Subject: [Bug tree-optimization/32328] [4.2/4.3 Regression] -fstrict-aliasing causes skipped code
- References: <bug-32328-14702@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #19 from rguenth at gcc dot gnu dot org 2007-07-16 15:51 -------
The backported patch causes
FAIL: gcc.c-torture/execute/pr28778.c execution, -O2
FAIL: gcc.c-torture/execute/pr28778.c execution, -Os
DCE removes
-
-<L1>:;
- list[3] = 42;
we have one added constraint:
blist.0_7 = blist_1
+*blist.0_7 = &ANYTHING
ESCAPED_VARS = blist.0_7
IL differences after alias1 are
@@ -251,12 +247,11 @@
list[3] = 42;
blist_6 = &list;
- # list_8 = PHI <list_4(3), list_5(4)>;
# blist_1 = PHI <blist_3(3), blist_6(4)>;
<L2>:;
blist.0_7 = (const GLint *) blist_1;
- # list_10 = V_MAY_DEF <list_8>;
- # NONLOCAL.44_11 = V_MAY_DEF <NONLOCAL.44_9>;
+ # NONLOCAL.44_10 = V_MAY_DEF <NONLOCAL.44_8>;
+ # SMT.45_11 = V_MAY_DEF <SMT.45_9>;
aglChoosePixelFormat (blist.0_7);
return;
we also have
+NULL = &ANYTHING
but this doesn't result in IL differences.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32328