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* [Bug tree-optimization/15473] New: [tree-ssa] Sibcall optimization for libcalls. @ 2004-05-17 0:47 kazu at cs dot umass dot edu 2004-05-17 0:57 ` [Bug tree-optimization/15473] " pinskia at gcc dot gnu dot org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: kazu at cs dot umass dot edu @ 2004-05-17 0:47 UTC (permalink / raw) To: gcc-bugs Consider: long long foo (long long a, long long b) { return a / b; } I get: foo (a, b) { <bb 0>: return a_1 / b_2; } with the assembly code being foo: subl $12, %esp pushl 28(%esp) pushl 28(%esp) pushl 28(%esp) pushl 28(%esp) call __divdi3 addl $28, %esp ret Note that the sequence of 4 pushl instructions simply copy 16 bytes from one location of the stack to another. If I create a (non-libcall) function with the same arguments like so long long div64 (long long a, long long b); long long bar (long long a, long long b) { return div64 (a, b); } I get: bar (a, b) { long long int T.0; <bb 0>: T.0_3 = div64 (a_1, b_2) [tail call]; return T.0_3; } with the assembly code being bar: jmp div64 -- Summary: [tree-ssa] Sibcall optimization for libcalls. Product: gcc Version: 3.5.0 Status: UNCONFIRMED Keywords: pessimizes-code Severity: enhancement Priority: P2 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: kazu at cs dot umass dot edu CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15473 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/15473] [tree-ssa] Sibcall optimization for libcalls. 2004-05-17 0:47 [Bug tree-optimization/15473] New: [tree-ssa] Sibcall optimization for libcalls kazu at cs dot umass dot edu @ 2004-05-17 0:57 ` pinskia at gcc dot gnu dot org 2004-05-17 19:33 ` [Bug rtl-optimization/15473] " steven at gcc dot gnu dot org 2004-08-16 0:19 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-05-17 0:57 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-05-16 11:31 ------- Confirmed, in fact it the ones done by builtin functions are already done on the tree-ssa which did not happen before the tree-ssa. -- What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever Confirmed| |1 Last reconfirmed|0000-00-00 00:00:00 |2004-05-16 11:31:55 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15473 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug rtl-optimization/15473] Sibcall optimization for libcalls. 2004-05-17 0:47 [Bug tree-optimization/15473] New: [tree-ssa] Sibcall optimization for libcalls kazu at cs dot umass dot edu 2004-05-17 0:57 ` [Bug tree-optimization/15473] " pinskia at gcc dot gnu dot org @ 2004-05-17 19:33 ` steven at gcc dot gnu dot org 2004-08-16 0:19 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: steven at gcc dot gnu dot org @ 2004-05-17 19:33 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From steven at gcc dot gnu dot org 2004-05-17 06:52 ------- This is not a tree-ssa problem, we don't even know about libcalls at the tree level (that's the whole point! or at least, one of them). If anything, this is an rtl optimization problem. This also is not code pessimization, just lack of an optimization. Please use that keyword when we _pessimize_ your code (ie "make it worse than without optimization"). You might be able to fix this when the tree profiling branch is merged. At that point you'd have the CFG, and perhaps (but I'm not sure) you can teach calls.c to build the libcall as a sibcall. -- What |Removed |Added ---------------------------------------------------------------------------- Component|tree-optimization |rtl-optimization Summary|[tree-ssa] Sibcall |Sibcall optimization for |optimization for libcalls. |libcalls. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15473 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug rtl-optimization/15473] Sibcall optimization for libcalls. 2004-05-17 0:47 [Bug tree-optimization/15473] New: [tree-ssa] Sibcall optimization for libcalls kazu at cs dot umass dot edu 2004-05-17 0:57 ` [Bug tree-optimization/15473] " pinskia at gcc dot gnu dot org 2004-05-17 19:33 ` [Bug rtl-optimization/15473] " steven at gcc dot gnu dot org @ 2004-08-16 0:19 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-08-16 0:19 UTC (permalink / raw) To: gcc-bugs -- What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Last reconfirmed|2004-05-16 11:31:55 |2004-08-16 00:19:18 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15473 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2004-08-16 0:19 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2004-05-17 0:47 [Bug tree-optimization/15473] New: [tree-ssa] Sibcall optimization for libcalls kazu at cs dot umass dot edu 2004-05-17 0:57 ` [Bug tree-optimization/15473] " pinskia at gcc dot gnu dot org 2004-05-17 19:33 ` [Bug rtl-optimization/15473] " steven at gcc dot gnu dot org 2004-08-16 0:19 ` pinskia at gcc dot gnu dot org
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