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| author | Richard Biener <rguenther@suse.de> | 2022-08-19 15:11:14 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-09-29 09:34:00 +0200 |
| commit | a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d (patch) | |
| tree | 67f6b47a8a794aa643f366698bf2ee4e8407d691 | |
| parent | f758d447d7f4699253c9f8ee345ba9b8357cdb22 (diff) | |
| download | gcc-a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d.zip gcc-a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d.tar.gz gcc-a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d.tar.bz2 | |
tree-optimization/105646 - re-interpret always executed in uninit diag
The following fixes PR105646, not diagnosing
int f1();
int f3(){
auto const & a = f1();
bool v3{v3};
return a;
}
with optimization because the early uninit diagnostic pass only
diagnoses always executed cases. The patch does this by
re-interpreting what always executed means and choosing to
ignore exceptional and abnormal control flow for this. At the
same time it improves things as suggested in a comment - when
the value-numbering run done without optimizing figures there's
a fallthru path, consider blocks on it as always executed.
PR tree-optimization/105646
* tree-ssa-uninit.cc (warn_uninitialized_vars): Pre-compute
the set of fallthru reachable blocks from function entry
and use that to determine wlims.always_executed.
* g++.dg/uninit-pr105646.C: New testcase.
| -rw-r--r-- | gcc/testsuite/g++.dg/uninit-pr105646.C | 17 | ||||
| -rw-r--r-- | gcc/tree-ssa-uninit.cc | 10 |
2 files changed, 25 insertions, 2 deletions
diff --git a/gcc/testsuite/g++.dg/uninit-pr105646.C b/gcc/testsuite/g++.dg/uninit-pr105646.C new file mode 100644 index 0000000..48ceb98 --- /dev/null +++ b/gcc/testsuite/g++.dg/uninit-pr105646.C @@ -0,0 +1,17 @@ +// { dg-do compile } +// { dg-require-effective-target c++11 } +// { dg-options "-O2 -Wuninitialized" } + +int f1(); +int f2(){ + bool v2{v2}; // { dg-warning "is used uninitialized" } + auto const & a = f1(); + return a; +} +int f3(){ + auto const & a = f1(); + // Diagnose the following when optimizing and as unconditional + // uninitialized use despite f1 possibly throwing + bool v3{v3}; // { dg-warning "is used uninitialized" } + return a; +} diff --git a/gcc/tree-ssa-uninit.cc b/gcc/tree-ssa-uninit.cc index eae29f8..bde2399 100644 --- a/gcc/tree-ssa-uninit.cc +++ b/gcc/tree-ssa-uninit.cc @@ -991,14 +991,20 @@ warn_uninitialized_vars (bool wmaybe_uninit) auto_bb_flag ft_reachable (cfun); /* Mark blocks that are always executed when we ignore provably - not executed edges. */ + not executed and EH and abnormal edges. */ basic_block bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); while (!(bb->flags & ft_reachable)) { bb->flags |= ft_reachable; + edge e = find_fallthru_edge (bb->succs); + if (e && e->flags & EDGE_EXECUTABLE) + { + bb = e->dest; + continue; + } /* Find a single executable edge. */ edge_iterator ei; - edge e, ee = NULL; + edge ee = NULL; FOR_EACH_EDGE (e, ei, bb->succs) if (e->flags & EDGE_EXECUTABLE) { |