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| author | Richard Biener <rguenther@suse.de> | 2022-11-28 09:19:33 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-11-28 10:04:42 +0100 |
| commit | 238cf114de16518c6569f0cdd2c4d6211ac98a74 (patch) | |
| tree | f2d074e9a906b6019c3e3f9649ae8782ea172f09 | |
| parent | 0976b012d89e3d819d83cdaf0dab05925b3eb3a0 (diff) | |
| download | gcc-238cf114de16518c6569f0cdd2c4d6211ac98a74.zip gcc-238cf114de16518c6569f0cdd2c4d6211ac98a74.tar.gz gcc-238cf114de16518c6569f0cdd2c4d6211ac98a74.tar.bz2 | |
tree-optimization/107876 - unswitching of switch
The following shows a missed update of dominators when unswitching
removes unreachable edges from switch stmts it unswitches. Fixed
by wiping dominator info in that case.
PR tree-optimization/107876
* tree-ssa-loop-unswitch.cc (clean_up_after_unswitching): Wipe
dominator info if we removed an edge.
* g++.dg/tree-ssa/pr107876.C: New testcase.
| -rw-r--r-- | gcc/testsuite/g++.dg/tree-ssa/pr107876.C | 38 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-unswitch.cc | 10 |
2 files changed, 47 insertions, 1 deletions
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr107876.C b/gcc/testsuite/g++.dg/tree-ssa/pr107876.C new file mode 100644 index 0000000..6cff2f1 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr107876.C @@ -0,0 +1,38 @@ +// { dg-do compile } +// { dg-require-effective-target c++11 } +// { dg-options "-O2 -funswitch-loops --param max-unswitch-insns=5 -fdump-tree-unswitch-details" } + +class X { +public: + X(); + X(const X&); + X(const volatile X &); + ~X(); +}; + +X test17(int i) { + if (false) { + impossible: + if (i == 3) + return X(); + } + + while (true) { + X x; + if (i == 0) + return x; + if (i == 1) + break; + if (i == 2) + continue; + if (i == 3) + goto impossible; + if (i == 4) + __builtin_exit(1); + if (i == 5) + return x; + } + return X(); +} + +// { dg-final { scan-tree-dump "unswitching loop 1 on .switch. with condition: i_\[0-9\]+\\(D\\) == 2" "unswitch" } } diff --git a/gcc/tree-ssa-loop-unswitch.cc b/gcc/tree-ssa-loop-unswitch.cc index 186ae95..e8c9bd6 100644 --- a/gcc/tree-ssa-loop-unswitch.cc +++ b/gcc/tree-ssa-loop-unswitch.cc @@ -1631,6 +1631,7 @@ clean_up_after_unswitching (int ignored_edge_flag) basic_block bb; edge e; edge_iterator ei; + bool removed_edge = false; FOR_EACH_BB_FN (bb, cfun) { @@ -1655,7 +1656,10 @@ clean_up_after_unswitching (int ignored_edge_flag) to preserve its edge. But we can remove the non-default CASE sharing the edge. */ if (e != default_e) - remove_edge (e); + { + remove_edge (e); + removed_edge = true; + } } else { @@ -1672,6 +1676,10 @@ clean_up_after_unswitching (int ignored_edge_flag) FOR_EACH_EDGE (e, ei, bb->succs) e->flags &= ~ignored_edge_flag; } + + /* If we removed an edge we possibly have to recompute dominators. */ + if (removed_edge) + free_dominance_info (CDI_DOMINATORS); } /* Loop unswitching pass. */ |