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* [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering @ 2008-02-25 20:05 bergner at gcc dot gnu dot org 2008-02-25 20:51 ` [Bug rtl-optimization/35371] " bergner at gcc dot gnu dot org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: bergner at gcc dot gnu dot org @ 2008-02-25 20:05 UTC (permalink / raw) To: gcc-bugs We fail to correctly order the operands for the indexed store within the loop below. This seems to be caused by a missing REG_POINTER attribute, so the code added for PR28690 doesn't have a chance of getting the ordering correct. An interesting thing is that if we replace the global array with an "extern int *reg_values;", then we get the ordering correct. bergner@etna:~/gcc/tests> cat a2-loop.c int reg_values[1024]; void clear_table (unsigned int n) { unsigned int i; for (i = 0; i < n; i++) reg_values[i] = 0; } The "bad" code gen looks like (using -O2 -S): clear_table: cmpwi 0,3,0 beqlr- 0 lis 9,reg_values@ha slwi 3,3,2 la 9,reg_values@l(9) li 11,0 li 0,0 .p2align 4,,15 .L3: stwx 0,11,9 addi 11,11,4 cmpw 7,11,3 bne+ 7,.L3 blr It's another question on why this isn't using an update form store and branch on count loop, to halve the size of the loop. The loop size is particularly glaring when you use -O2 -funroll-loops, then we get 8 indexed stores (all with the wrong operand order) and 8 addi's...but I guess that's for another bugzilla. -- Summary: Missing REG_POINTER attribute causes bad indexed load/store operand ordering Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: bergner at gcc dot gnu dot org ReportedBy: bergner at gcc dot gnu dot org GCC build triplet: powerpc64-linux GCC host triplet: powerpc64-linux GCC target triplet: powerpc64-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35371 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/35371] Missing REG_POINTER attribute causes bad indexed load/store operand ordering 2008-02-25 20:05 [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering bergner at gcc dot gnu dot org @ 2008-02-25 20:51 ` bergner at gcc dot gnu dot org 2008-02-26 1:56 ` bergner at gcc dot gnu dot org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: bergner at gcc dot gnu dot org @ 2008-02-25 20:51 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from bergner at gcc dot gnu dot org 2008-02-25 20:50 ------- Created an attachment (id=15231) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15231&action=view) Patch to GCSE to copy REG_POINTER attribute over to new pseudos. The culprit here is GCSE. When GCSE creates a pseudo to copy a reaching expression into, it fails to copy the POINTER attribute over. I'm testing the attached patch. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35371 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/35371] Missing REG_POINTER attribute causes bad indexed load/store operand ordering 2008-02-25 20:05 [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering bergner at gcc dot gnu dot org 2008-02-25 20:51 ` [Bug rtl-optimization/35371] " bergner at gcc dot gnu dot org @ 2008-02-26 1:56 ` bergner at gcc dot gnu dot org 2008-02-26 1:57 ` bergner at gcc dot gnu dot org 2008-04-08 15:42 ` bergner at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: bergner at gcc dot gnu dot org @ 2008-02-26 1:56 UTC (permalink / raw) To: gcc-bugs -- bergner at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Ever Confirmed|0 |1 Last reconfirmed|0000-00-00 00:00:00 |2008-02-26 01:55:49 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35371 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/35371] Missing REG_POINTER attribute causes bad indexed load/store operand ordering 2008-02-25 20:05 [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering bergner at gcc dot gnu dot org 2008-02-25 20:51 ` [Bug rtl-optimization/35371] " bergner at gcc dot gnu dot org 2008-02-26 1:56 ` bergner at gcc dot gnu dot org @ 2008-02-26 1:57 ` bergner at gcc dot gnu dot org 2008-04-08 15:42 ` bergner at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: bergner at gcc dot gnu dot org @ 2008-02-26 1:57 UTC (permalink / raw) To: gcc-bugs -- bergner at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Known to fail| |4.3.0 4.4.0 Priority|P3 |P2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35371 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/35371] Missing REG_POINTER attribute causes bad indexed load/store operand ordering 2008-02-25 20:05 [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering bergner at gcc dot gnu dot org ` (2 preceding siblings ...) 2008-02-26 1:57 ` bergner at gcc dot gnu dot org @ 2008-04-08 15:42 ` bergner at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: bergner at gcc dot gnu dot org @ 2008-04-08 15:42 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from bergner at gcc dot gnu dot org 2008-04-08 15:41 ------- An updated patch (minus the rtlanal.c which has since been reverted) has fixed this problem. http://gcc.gnu.org/ml/gcc-patches/2008-03/msg02044.html -- bergner at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35371 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-04-08 15:42 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2008-02-25 20:05 [Bug rtl-optimization/35371] New: Missing REG_POINTER attribute causes bad indexed load/store operand ordering bergner at gcc dot gnu dot org 2008-02-25 20:51 ` [Bug rtl-optimization/35371] " bergner at gcc dot gnu dot org 2008-02-26 1:56 ` bergner at gcc dot gnu dot org 2008-02-26 1:57 ` bergner at gcc dot gnu dot org 2008-04-08 15:42 ` bergner at gcc dot gnu dot org
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