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* [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store @ 2012-09-28 10:03 joey.ye at arm dot com 2012-09-28 10:47 ` [Bug tree-optimization/54733] " rguenth at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: joey.ye at arm dot com @ 2012-09-28 10:03 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54733 Bug #: 54733 Summary: Missing opportunity to optimize endian independent load/store Classification: Unclassified Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: joey.ye@arm.com This case tries to load from memory in little-endian way, no matter what endianess current target is. On trunk 4.8 little-endian target, two byte loads should be able to combined into a single 16-byte load. int read_aux(void *, int); int read_le() { unsigned char data[2]; read_aux(data, 2); return data[0] | (data[1]<<8); } Current Tree (optimized): unsigned char data[2]; read_aux (&data, 2); D.4064_1 = data[0]; D.4065_2 = (int) D.4064_1; D.4066_3 = data[1]; D.4067_4 = (int) D.4066_3; D.4068_5 = D.4067_4 << 8; D.4063_6 = D.4068_5 | D.4065_2; data ={v} {CLOBBER}; return D.4063_6; Expected Tree (optimized): unsigned char data[2]; unsigned short *temp; unsigned in D.4064; read_aux (&data, 2); temp=&data; D.4064_1 = *temp; return D.4064_1; ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/54733] Missing opportunity to optimize endian independent load/store 2012-09-28 10:03 [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store joey.ye at arm dot com @ 2012-09-28 10:47 ` rguenth at gcc dot gnu.org 2014-03-19 6:31 ` thomas.preudhomme at arm dot com ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2012-09-28 10:47 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54733 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Status|UNCONFIRMED |NEW Last reconfirmed| |2012-09-28 Ever Confirmed|0 |1 --- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-28 10:47:44 UTC --- Confirmed. The original idea was to leverage the byte-swap pass for this. First you need to extend that to work on a memory source (which it currently does not handle), then you, in addition to detecting bswap, emit a word load and detect the "noop" pattern which then skips bswap. (the byte-swap pass was also supposed to utilize the vector shuffle engine for non-bswap shuffles). ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/54733] Missing opportunity to optimize endian independent load/store 2012-09-28 10:03 [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store joey.ye at arm dot com 2012-09-28 10:47 ` [Bug tree-optimization/54733] " rguenth at gcc dot gnu.org @ 2014-03-19 6:31 ` thomas.preudhomme at arm dot com 2014-05-23 3:34 ` thopre01 at gcc dot gnu.org 2014-05-26 13:49 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: thomas.preudhomme at arm dot com @ 2014-03-19 6:31 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54733 Thomas Preud'homme <thomas.preudhomme at arm dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |thomas.preudhomme at arm dot com --- Comment #2 from Thomas Preud'homme <thomas.preudhomme at arm dot com> --- A patch to fix this is currently under discussion on gcc-patches at: http://gcc.gnu.org/ml/gcc-patches/2014-03/msg00925.html ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/54733] Missing opportunity to optimize endian independent load/store 2012-09-28 10:03 [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store joey.ye at arm dot com 2012-09-28 10:47 ` [Bug tree-optimization/54733] " rguenth at gcc dot gnu.org 2014-03-19 6:31 ` thomas.preudhomme at arm dot com @ 2014-05-23 3:34 ` thopre01 at gcc dot gnu.org 2014-05-26 13:49 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: thopre01 at gcc dot gnu.org @ 2014-05-23 3:34 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54733 --- Comment #3 from thopre01 at gcc dot gnu.org --- Author: thopre01 Date: Fri May 23 03:33:28 2014 New Revision: 210843 URL: http://gcc.gnu.org/viewcvs?rev=210843&root=gcc&view=rev Log: 2014-05-23 Thomas Preud'homme <thomas.preudhomme@arm.com> PR tree-optimization/54733 gcc/ * tree-ssa-math-opts.c (nop_stats): New "bswap_stats" structure. (CMPNOP): Define. (find_bswap_or_nop_load): New. (find_bswap_1): Renamed to ... (find_bswap_or_nop_1): This. Also add support for memory source. (find_bswap): Renamed to ... (find_bswap_or_nop): This. Also add support for memory source and detection of bitwise operations equivalent to load in host endianness. (execute_optimize_bswap): Likewise. Also move its leading comment back in place and split statement transformation into ... (bswap_replace): This. gcc/testsuite * gcc.dg/optimize-bswapdi-3.c: New test to check extension of bswap optimization to support memory sources and bitwise operations equivalent to load in host endianness. * gcc.dg/optimize-bswaphi-1.c: Likewise. * gcc.dg/optimize-bswapsi-2.c: Likewise. * gcc.c-torture/execute/bswap-2.c: Likewise. Added: trunk/gcc/testsuite/gcc.c-torture/execute/bswap-2.c trunk/gcc/testsuite/gcc.dg/optimize-bswapdi-3.c trunk/gcc/testsuite/gcc.dg/optimize-bswaphi-1.c trunk/gcc/testsuite/gcc.dg/optimize-bswapsi-2.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-ssa-math-opts.c ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/54733] Missing opportunity to optimize endian independent load/store 2012-09-28 10:03 [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store joey.ye at arm dot com ` (2 preceding siblings ...) 2014-05-23 3:34 ` thopre01 at gcc dot gnu.org @ 2014-05-26 13:49 ` rguenth at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2014-05-26 13:49 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54733 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |FIXED Target Milestone|--- |4.10.0 --- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- Fixed. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-05-26 13:49 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-09-28 10:03 [Bug tree-optimization/54733] New: Missing opportunity to optimize endian independent load/store joey.ye at arm dot com 2012-09-28 10:47 ` [Bug tree-optimization/54733] " rguenth at gcc dot gnu.org 2014-03-19 6:31 ` thomas.preudhomme at arm dot com 2014-05-23 3:34 ` thopre01 at gcc dot gnu.org 2014-05-26 13:49 ` rguenth at gcc dot gnu.org
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