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* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> @ 2005-11-25 6:17 ` pinskia at gcc dot gnu dot org 2005-11-26 18:08 ` pinskia at gcc dot gnu dot org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-11-25 6:17 UTC (permalink / raw) To: gcc-bugs ------- Comment #4 from pinskia at gcc dot gnu dot org 2005-11-25 06:17 ------- Ok, I have a patch which copies the code for Real divides into the int divides, though it adds !flag_wrapv. Though I am worry about the non truncate divide, I think it should be the same for them but for some reason I am worried. -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |pinskia at gcc dot gnu dot |dot org |org Status|NEW |ASSIGNED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> 2005-11-25 6:17 ` [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv pinskia at gcc dot gnu dot org @ 2005-11-26 18:08 ` pinskia at gcc dot gnu dot org 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-11-26 18:08 UTC (permalink / raw) To: gcc-bugs ------- Comment #5 from pinskia at gcc dot gnu dot org 2005-11-26 18:08 ------- Patch posted: http://gcc.gnu.org/ml/gcc-patches/2005-11/msg01850.html -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- URL| |http://gcc.gnu.org/ml/gcc- | |patches/2005- | |11/msg01850.html Keywords| |patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> 2005-11-25 6:17 ` [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv pinskia at gcc dot gnu dot org 2005-11-26 18:08 ` pinskia at gcc dot gnu dot org @ 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org 2005-12-12 20:09 ` pinskia at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-11-26 22:18 UTC (permalink / raw) To: gcc-bugs ------- Comment #6 from pinskia at gcc dot gnu dot org 2005-11-26 22:18 ------- Subject: Bug 23669 Author: pinskia Date: Sat Nov 26 22:18:04 2005 New Revision: 107543 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107543 Log: 2005-11-26 Andrew Pinski <pinskia@physics.uc.edu> PR middle-end/23669 * fold-const.c (fold_binary): Convert -A/-B to A/B for signed types when overflow is undefined. 2005-11-26 Andrew Pinski <pinskia@physics.uc.edu> PR middle-end/23669 * gcc.dg/tree-ssa/divide-1.c: New test. * gcc.dg/tree-ssa/divide-2.c: New test. Added: trunk/gcc/testsuite/gcc.dg/tree-ssa/divide-1.c trunk/gcc/testsuite/gcc.dg/tree-ssa/divide-2.c Modified: trunk/gcc/ChangeLog trunk/gcc/fold-const.c trunk/gcc/testsuite/ChangeLog -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> ` (2 preceding siblings ...) 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org @ 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org 2005-12-12 20:09 ` pinskia at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-11-26 22:18 UTC (permalink / raw) To: gcc-bugs ------- Comment #7 from pinskia at gcc dot gnu dot org 2005-11-26 22:18 ------- Fixed. -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> ` (3 preceding siblings ...) 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org @ 2005-12-12 20:09 ` pinskia at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-12-12 20:09 UTC (permalink / raw) To: gcc-bugs -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |4.2.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] New: fold does convert (-a)/10 into a/-10. @ 2005-09-01 2:04 pinskia at gcc dot gnu dot org 2005-10-01 17:34 ` [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv pinskia at gcc dot gnu dot org 0 siblings, 1 reply; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-09-01 2:04 UTC (permalink / raw) To: gcc-bugs Another idea from LLVM. The following two functions should be the same asm: int f(int a) { return (-a)/10; } int f1(int a) { return a/-10; } ---- We currently get on PPC: _f: lis r0,0x6666 neg r3,r3 ori r0,r0,26215 mulhw r0,r3,r0 srawi r3,r3,31 srawi r0,r0,2 subf r3,r3,r0 blr _f1: lis r0,0x6666 ori r0,r0,26215 mulhw r0,r3,r0 srawi r3,r3,31 srawi r0,r0,2 subf r3,r0,r3 blr As you can see f1 has one less instruction which should be better. -- Summary: fold does convert (-a)/10 into a/-10. Product: gcc Version: 4.1.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P2 Component: middle-end AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: pinskia at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org OtherBugsDependingO 19987 nThis: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv 2005-09-01 2:04 [Bug middle-end/23669] New: fold does convert (-a)/10 into a/-10 pinskia at gcc dot gnu dot org @ 2005-10-01 17:34 ` pinskia at gcc dot gnu dot org 0 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-10-01 17:34 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-10-01 17:34 ------- (In reply to comment #2) > Those expressions are only the same for floating point types. But -a for INT_MIN is undefined for signed type since it is an overflow. So the conversion is only valid for -fno-wrapv which is default for C, C++, Ada, and fortran. -- What |Removed |Added ---------------------------------------------------------------------------- Summary|fold does convert (-a)/10 |fold does convert (-a)/10 |into a/-10. |into a/-10 with -fno-wrapv http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23669 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-12-12 20:09 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <bug-23669-6528@http.gcc.gnu.org/bugzilla/> 2005-11-25 6:17 ` [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv pinskia at gcc dot gnu dot org 2005-11-26 18:08 ` pinskia at gcc dot gnu dot org 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org 2005-11-26 22:18 ` pinskia at gcc dot gnu dot org 2005-12-12 20:09 ` pinskia at gcc dot gnu dot org 2005-09-01 2:04 [Bug middle-end/23669] New: fold does convert (-a)/10 into a/-10 pinskia at gcc dot gnu dot org 2005-10-01 17:34 ` [Bug middle-end/23669] fold does convert (-a)/10 into a/-10 with -fno-wrapv pinskia at gcc dot gnu dot org
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