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* [Bug tree-optimization/36228] New: redundant runtime check while vectorizing @ 2008-05-13 13:00 razya at il dot ibm dot com 2008-05-13 13:41 ` [Bug tree-optimization/36228] " rguenth at gcc dot gnu dot org ` (4 more replies) 0 siblings, 5 replies; 6+ messages in thread From: razya at il dot ibm dot com @ 2008-05-13 13:00 UTC (permalink / raw) To: gcc-bugs /* { dg-do compile } */ /* { dg-options "-O3 -c" } */ #define COLS 8 #define ROWS 8 int t_run_test(void); int t_run_test() { int k_1,i_1, j_1; static signed char f_1[ROWS][COLS] ; static long F_1[ROWS][COLS] ; long cosMatrixA[ROWS][COLS] ; for( k_1 = 0 ; k_1 < COLS ; k_1++ ) { for( i_1 = 0 ; i_1 < ROWS ; i_1++ ) { for( j_1 = 0 ; j_1 < COLS ; j_1++ ) F_1[i_1][j_1] += f_1[i_1][k_1] * cosMatrixA[k_1][j_1] ; } } return 0; } A redundant check for aliasing is created. Looking at the vectorizer's dump, we see: versioning for alias required: can't determine dependence between F_1[i_1_41][j_1_42] and F_1[i_1_41][j_1_42] Tested on Power6. -- Summary: redundant runtime check while vectorizing Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: razya at il dot ibm dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/36228] redundant runtime check while vectorizing 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com @ 2008-05-13 13:41 ` rguenth at gcc dot gnu dot org 2008-05-14 3:59 ` spop at gcc dot gnu dot org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu dot org @ 2008-05-13 13:41 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from rguenth at gcc dot gnu dot org 2008-05-13 13:40 ------- I belive this is a known issue with the data-dependence analyzer? (I never understood why it doesn't recognize identical references...) -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |spop at gcc dot gnu dot org Severity|normal |enhancement Keywords| |missed-optimization http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/36228] redundant runtime check while vectorizing 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com 2008-05-13 13:41 ` [Bug tree-optimization/36228] " rguenth at gcc dot gnu dot org @ 2008-05-14 3:59 ` spop at gcc dot gnu dot org 2008-05-15 21:56 ` sebpop at gmail dot com ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: spop at gcc dot gnu dot org @ 2008-05-14 3:59 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from spop at gcc dot gnu dot org 2008-05-14 03:59 ------- Subject: Re: redundant runtime check while vectorizing How costly would it be if we do as a first data dependence test a call to operand_equal_p on the array references? That certainly would avoid lot of computations downstream in the data dependence test, but would be applied as an initial test to all dependence relations. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/36228] redundant runtime check while vectorizing 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com 2008-05-13 13:41 ` [Bug tree-optimization/36228] " rguenth at gcc dot gnu dot org 2008-05-14 3:59 ` spop at gcc dot gnu dot org @ 2008-05-15 21:56 ` sebpop at gmail dot com 2008-05-15 22:01 ` rguenth at gcc dot gnu dot org 2008-05-16 16:47 ` spop at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: sebpop at gmail dot com @ 2008-05-15 21:56 UTC (permalink / raw) To: gcc-bugs ------- Comment #3 from sebpop at gmail dot com 2008-05-15 21:55 ------- Subject: Re: redundant runtime check while vectorizing Here is a patch for this: > a first data dependence test a call to operand_equal_p on the array references Tested with vect.exp and tree-ssa.exp. I will send another email to gcc-patches with the patch once it passes the tests on gccfarm. Sebastian ------- Comment #4 from sebpop at gmail dot com 2008-05-15 21:55 ------- Created an attachment (id=15643) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15643&action=view) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/36228] redundant runtime check while vectorizing 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com ` (2 preceding siblings ...) 2008-05-15 21:56 ` sebpop at gmail dot com @ 2008-05-15 22:01 ` rguenth at gcc dot gnu dot org 2008-05-16 16:47 ` spop at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu dot org @ 2008-05-15 22:01 UTC (permalink / raw) To: gcc-bugs ------- Comment #5 from rguenth at gcc dot gnu dot org 2008-05-15 22:01 ------- operand_equal_p is reasonably cheap. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/36228] redundant runtime check while vectorizing 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com ` (3 preceding siblings ...) 2008-05-15 22:01 ` rguenth at gcc dot gnu dot org @ 2008-05-16 16:47 ` spop at gcc dot gnu dot org 4 siblings, 0 replies; 6+ messages in thread From: spop at gcc dot gnu dot org @ 2008-05-16 16:47 UTC (permalink / raw) To: gcc-bugs ------- Comment #7 from spop at gcc dot gnu dot org 2008-05-16 16:46 ------- Fixed. -- spop at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36228 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2008-05-16 16:47 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2008-05-13 13:00 [Bug tree-optimization/36228] New: redundant runtime check while vectorizing razya at il dot ibm dot com 2008-05-13 13:41 ` [Bug tree-optimization/36228] " rguenth at gcc dot gnu dot org 2008-05-14 3:59 ` spop at gcc dot gnu dot org 2008-05-15 21:56 ` sebpop at gmail dot com 2008-05-15 22:01 ` rguenth at gcc dot gnu dot org 2008-05-16 16:47 ` spop at gcc dot gnu dot org
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