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* [Bug tree-optimization/54810] New: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR @ 2012-10-04 9:48 jakub at gcc dot gnu.org 2012-10-04 9:56 ` [Bug tree-optimization/54810] " jakub at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: jakub at gcc dot gnu.org @ 2012-10-04 9:48 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54810 Bug #: 54810 Summary: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: jakub@gcc.gnu.org struct S { unsigned long w; void (*u) (void *, unsigned int, unsigned int); }; struct T; typedef void (*a_t) (struct T *); typedef void (*b_t) (struct T *); struct T { a_t a; b_t b; struct S c; int d, e, f; }; _Bool fn1 (struct T *, unsigned int); int fn2 (struct T *, unsigned int, void *, unsigned long); int fn3 (struct T *, unsigned int, unsigned int *); static _Bool foo (struct T *x, unsigned int y, unsigned int z) { unsigned int i; for (i = 0; i < z; i++) if (!fn1 (x, y + i)) return 0; return 1; } int bar (struct T *x, unsigned int y, void *z, unsigned long s) { unsigned long w = x->c.w; unsigned long q = s / w; unsigned int v; int r, i; if (s % x->c.w) return -22; if (y % x->d) return -22; x->a (x); if (foo (x, y, q) || x->f || x->e == 0) r = fn2 (x, y, z, s); else for (i = 0; i < q; i++) { r = fn3 (x, y + (i * x->d), &v); if (r != 0) break; x->c.u (z + (i * w), v, 0); } x->b (x); return r; } reports at -O2 -Wall maybe uninitialized warning. While generally it is IMHO an acceptable false positive, especially if foo doesn't get inlined, this testcase lead to me find out that while we handle _7 = _4 & 0xffff; if (_7 == 0) goto bbX; by adding ASSERT_EXPRs for _4 (in the _7 != 0 code _4 is known to be non-zero, in the _7 == 0 code it can e.g. have [0, 0xffff0000] range), we don't handle _7 = (unsigned short) _4; if (_7 == 0) goto bbX; the same way. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/54810] VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR 2012-10-04 9:48 [Bug tree-optimization/54810] New: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR jakub at gcc dot gnu.org @ 2012-10-04 9:56 ` jakub at gcc dot gnu.org 2012-10-04 10:03 ` pinskia at gcc dot gnu.org 2012-10-05 9:38 ` jakub at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: jakub at gcc dot gnu.org @ 2012-10-04 9:56 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54810 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2012-10-04 AssignedTo|unassigned at gcc dot |jakub at gcc dot gnu.org |gnu.org | Ever Confirmed|0 |1 --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-04 09:55:25 UTC --- Created attachment 28356 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28356 gcc48-pr54810.patch Untested patch. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/54810] VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR 2012-10-04 9:48 [Bug tree-optimization/54810] New: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR jakub at gcc dot gnu.org 2012-10-04 9:56 ` [Bug tree-optimization/54810] " jakub at gcc dot gnu.org @ 2012-10-04 10:03 ` pinskia at gcc dot gnu.org 2012-10-05 9:38 ` jakub at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2012-10-04 10:03 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54810 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pinskia at gcc dot gnu.org Severity|normal |enhancement ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/54810] VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR 2012-10-04 9:48 [Bug tree-optimization/54810] New: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR jakub at gcc dot gnu.org 2012-10-04 9:56 ` [Bug tree-optimization/54810] " jakub at gcc dot gnu.org 2012-10-04 10:03 ` pinskia at gcc dot gnu.org @ 2012-10-05 9:38 ` jakub at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: jakub at gcc dot gnu.org @ 2012-10-05 9:38 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54810 --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-05 09:37:32 UTC --- Author: jakub Date: Fri Oct 5 09:37:25 2012 New Revision: 192115 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192115 Log: PR tree-optimization/54810 * tree-vrp.c (register_edge_assert_for_2): Handle NAME = (unsigned) NAME2; if (NAME cmp CST) for narrowing casts to unsigned integral type like NAME = NAME2 & CST2; if (NAME cmp CST) where CST2 is the max value of the unsigned integral type. * gcc.dg/tree-ssa/vrp85.c: New test. Added: trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp85.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-vrp.c ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-10-05 9:38 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-10-04 9:48 [Bug tree-optimization/54810] New: VRP doesn't handle comparison of narrowing cast like comparison of BIT_AND_EXPR jakub at gcc dot gnu.org 2012-10-04 9:56 ` [Bug tree-optimization/54810] " jakub at gcc dot gnu.org 2012-10-04 10:03 ` pinskia at gcc dot gnu.org 2012-10-05 9:38 ` jakub at gcc dot gnu.org
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