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* [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets @ 2011-01-10 0:01 kkojima at gcc dot gnu.org 2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: kkojima at gcc dot gnu.org @ 2011-01-10 0:01 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239 Summary: (int)&func & 3 is always optimized to 0 on some targets Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: kkojima@gcc.gnu.org Targets like arm, hppa and sh64 use the lower bits of the address of functions for special purposes. Even on those targets, ---- extern void plabel32_function (void); int is_plabel32 (void) { return ((unsigned long) &plabel32_function & 3); } ---- which was the test case of PR 35705, is wrongly compiled with -O2. It seems that tree-bit-ccp optimization evaluates the expression ((unsigned long) &plabel32_function & 3) to zero always. With -fno-tree-bit-ccp, the result looks OK. For example, arm-eabi compiler outputs mov r0, #0 bx lr with -O2 and ldr r0, .L2 and r0, r0, #3 bx lr .L3: .align 2 .L2: .word plabel32_function with -O2 -fno-tree-bit-ccp. I've got similar results for hppa and sh64 compilers. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets 2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org @ 2011-01-11 13:03 ` rguenth at gcc dot gnu.org 2011-01-11 14:33 ` rguenth at gcc dot gnu.org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2011-01-11 13:03 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2011.01.11 12:53:34 AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org |gnu.org | Target Milestone|--- |4.6.0 Summary|(int)&func & 3 is always |[4.6 Regression] (int)&func |optimized to 0 on some |& 3 is always optimized to |targets |0 on some targets Ever Confirmed|0 |1 --- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-11 12:53:34 UTC --- Confirmed, mine. The fix for PR35705 only extracts alignment information from function decls for the single case &fn & 1. That's odd. I'm going to simply punt for function-decls for now. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets 2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org 2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org @ 2011-01-11 14:33 ` rguenth at gcc dot gnu.org 2011-01-11 23:17 ` kkojima at gcc dot gnu.org 2011-01-12 13:10 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2011-01-11 14:33 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239 --- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-11 14:23:23 UTC --- Author: rguenth Date: Tue Jan 11 14:23:20 2011 New Revision: 168661 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=168661 Log: 2011-01-11 Richard Guenther <rguenther@suse.de> PR tree-optimization/47239 * tree-ssa-ccp.c (get_value_from_alignment): Punt for FUNCTION_DECLs. Modified: trunk/gcc/ChangeLog trunk/gcc/tree-ssa-ccp.c ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets 2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org 2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org 2011-01-11 14:33 ` rguenth at gcc dot gnu.org @ 2011-01-11 23:17 ` kkojima at gcc dot gnu.org 2011-01-12 13:10 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: kkojima at gcc dot gnu.org @ 2011-01-11 23:17 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239 --- Comment #3 from Kazumoto Kojima <kkojima at gcc dot gnu.org> 2011-01-11 23:14:45 UTC --- I've tried 168661 with arm, hppa and sh64 cc1's. The problem has gone away on all these 3 targets. Thanks! ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets 2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org ` (2 preceding siblings ...) 2011-01-11 23:17 ` kkojima at gcc dot gnu.org @ 2011-01-12 13:10 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2011-01-12 13:10 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED --- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-12 12:10:05 UTC --- Fixed. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-01-12 12:10 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org 2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org 2011-01-11 14:33 ` rguenth at gcc dot gnu.org 2011-01-11 23:17 ` kkojima at gcc dot gnu.org 2011-01-12 13:10 ` rguenth at gcc dot gnu.org
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