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* [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included @ 2015-01-20 13:32 philipp.gschwandtner at uibk dot ac.at 2015-01-20 14:10 ` [Bug tree-optimization/64689] " trippels at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: philipp.gschwandtner at uibk dot ac.at @ 2015-01-20 13:32 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64689 Bug ID: 64689 Summary: tree-vectorize generates wrong code with inlined function - minimum working example included Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: philipp.gschwandtner at uibk dot ac.at Created attachment 34500 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34500&action=edit minimum working example The tree vectorizer in gcc 4.7-4.9 appears to generate semantically incorrect code for the particular case clarified in the attached minimum working example. gcc 4.6.3 does not show this issue. In gcc 4.7.3 only one of the checks fails, in gcc 4.8.3 and 4.9.2 both of them fail (as these versions also seem to recognize case A as vectorizable). Testing was performed on an Intel Xeon E5-2699 v3 Haswell CPU running a 3.10.0-123.13.1.el7.x86_64 Linux kernel. Compile with: gcc test.c -o test -O3 -std=c99 -pedantic -Wall -Wextra -fwrapv -fno-strict-aliasing Expected output (equals gcc 4.6.3 output): Checking case A: EQUAL! Checking case B: EQUAL! Actual output (for gcc 4.8.3 and 4.9.2): Checking case A: NOT EQUAL! C1: -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, C2: -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, Checking case B: NOT EQUAL! C1: -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, C2: -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, Above output is produced when compiled with gcc 4.9.2 and 4.8.3. For gcc 4.7.3 the check for case A succeeds while the check for case B still fails. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/64689] tree-vectorize generates wrong code with inlined function - minimum working example included 2015-01-20 13:32 [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included philipp.gschwandtner at uibk dot ac.at @ 2015-01-20 14:10 ` trippels at gcc dot gnu.org 2015-01-21 9:33 ` philipp.gschwandtner at uibk dot ac.at 2015-01-21 9:38 ` trippels at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: trippels at gcc dot gnu.org @ 2015-01-20 14:10 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64689 Markus Trippelsdorf <trippels at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED CC| |trippels at gcc dot gnu.org Resolution|--- |INVALID --- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- Compile with gcc-5 and use -fsanitize=undefined: markus@x4 tmp % gcc -fsanitize=undefined test.c -o test -O3 -std=c99 -pedantic -Wall -Wextra -fwrapv -fno-strict-aliasing markus@x4 tmp % ./test test.c:67:21: runtime error: shift exponent -4 is negative test.c:68:21: runtime error: shift exponent -4 is negative ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/64689] tree-vectorize generates wrong code with inlined function - minimum working example included 2015-01-20 13:32 [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included philipp.gschwandtner at uibk dot ac.at 2015-01-20 14:10 ` [Bug tree-optimization/64689] " trippels at gcc dot gnu.org @ 2015-01-21 9:33 ` philipp.gschwandtner at uibk dot ac.at 2015-01-21 9:38 ` trippels at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: philipp.gschwandtner at uibk dot ac.at @ 2015-01-21 9:33 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64689 --- Comment #2 from Philipp Gschwandtner <philipp.gschwandtner at uibk dot ac.at> --- Thanks for the quick reply, it's an excerpt from a larger code and I wasn't aware that it's actually not C-compliant. Maybe gcc bug submission guidelines should include compiling/running with -fsanitize to check for issues like that. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/64689] tree-vectorize generates wrong code with inlined function - minimum working example included 2015-01-20 13:32 [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included philipp.gschwandtner at uibk dot ac.at 2015-01-20 14:10 ` [Bug tree-optimization/64689] " trippels at gcc dot gnu.org 2015-01-21 9:33 ` philipp.gschwandtner at uibk dot ac.at @ 2015-01-21 9:38 ` trippels at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: trippels at gcc dot gnu.org @ 2015-01-21 9:38 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64689 --- Comment #3 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- (In reply to Philipp Gschwandtner from comment #2) > Thanks for the quick reply, it's an excerpt from a larger code and I wasn't > aware that it's actually not C-compliant. > > Maybe gcc bug submission guidelines should include compiling/running with > -fsanitize to check for issues like that. Yes, that is a good idea. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-01-21 9:38 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-01-20 13:32 [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included philipp.gschwandtner at uibk dot ac.at 2015-01-20 14:10 ` [Bug tree-optimization/64689] " trippels at gcc dot gnu.org 2015-01-21 9:33 ` philipp.gschwandtner at uibk dot ac.at 2015-01-21 9:38 ` trippels at gcc dot gnu.org
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