| Message ID | alpine.LNX.2.00.1209041121380.28649@zhemvz.fhfr.qr |
|---|---|
| State | New |
| Headers | show |
On 2012.09.04 at 11:22 +0200, Richard Guenther wrote: > > This fixes PR54458 where DOM jump threading turns a loop into > one with multiple latches but does not mark it so. > > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk. > > Richard. > > 2012-09-04 Richard Guenther <rguenther@suse.de> > > PR tree-optimization/54458 > * tree-ssa-threadupdate.c (thread_through_loop_header): If we > turn the loop into one with multiple latches mark it so. This commit causes http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54520
Index: gcc/tree-ssa-threadupdate.c =================================================================== --- gcc/tree-ssa-threadupdate.c (revision 190889) +++ gcc/tree-ssa-threadupdate.c (working copy) @@ -1037,11 +1037,21 @@ thread_through_loop_header (struct loop } free (bblocks); + /* If the new header has multiple latches mark it so. */ + FOR_EACH_EDGE (e, ei, loop->header->preds) + if (e->src->loop_father == loop + && e->src != loop->latch) + { + loop->latch = NULL; + loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES); + } + /* Cancel remaining threading requests that would make the loop a multiple entry loop. */ FOR_EACH_EDGE (e, ei, header->preds) { edge e2; + if (e->aux == NULL) continue; Index: gcc/testsuite/gcc.dg/torture/pr54458.c =================================================================== --- gcc/testsuite/gcc.dg/torture/pr54458.c (revision 0) +++ gcc/testsuite/gcc.dg/torture/pr54458.c (working copy) @@ -0,0 +1,20 @@ +/* { dg-do compile } */ + +unsigned int a, b, c; + +void +foo (unsigned int x) +{ + do + { + if (a == 0 ? 1 : 1 % a) + for (; b; b--) + lab:; + else + while (x) + ; + if (c) + goto lab; + } + while (1); +}