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| author | Jan Hubicka <jh@suse.cz> | 2022-06-24 13:52:44 +0200 |
|---|---|---|
| committer | Jan Hubicka <jh@suse.cz> | 2022-06-24 13:52:44 +0200 |
| commit | 7fd34782b95bbe1b4dc9936b8923f86d4aaee379 (patch) | |
| tree | fa668f35065c45cf9fd948e8f08572d4e351e561 /gcc | |
| parent | 268b5c81e93ac3ff44fc8ace22ce504d8faa4b07 (diff) | |
| download | gcc-7fd34782b95bbe1b4dc9936b8923f86d4aaee379.zip gcc-7fd34782b95bbe1b4dc9936b8923f86d4aaee379.tar.gz gcc-7fd34782b95bbe1b4dc9936b8923f86d4aaee379.tar.bz2 | |
Fix stmt_kills_ref_p WRT external throws
Add missing check to stmt_kills_ref_p for case that function
is terminated by EH before call return value kills the ref. In the PR
I tried to construct testcase but I don't know how to do that until I
annotate EH code with fnspec attributes which I will do in separate patch
and add a testcase.
PR ipa/106057
* tree-ssa-alias.cc (stmt_kills_ref_p): Check for external throw.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/tree-ssa-alias.cc | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc index b1e7a2d..782266b 100644 --- a/gcc/tree-ssa-alias.cc +++ b/gcc/tree-ssa-alias.cc @@ -87,10 +87,11 @@ along with GCC; see the file COPYING3. If not see This function tries to disambiguate two reference trees. - bool ptr_deref_may_alias_global_p (tree) + bool ptr_deref_may_alias_global_p (tree, bool) This function queries if dereferencing a pointer variable may - alias global memory. + alias global memory. If bool argument is true, global memory + is considered to also include function local memory that escaped. More low-level disambiguators are available and documented in this file. Low-level disambiguators dealing with points-to @@ -3333,11 +3334,18 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref) && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME /* The assignment is not necessarily carried out if it can throw and we can catch it in the current function where we could inspect - the previous value. + the previous value. Similarly if the function can throw externally + and the ref does not die on the function return. ??? We only need to care about the RHS throwing. For aggregate assignments or similar calls and non-call exceptions the LHS - might throw as well. */ - && !stmt_can_throw_internal (cfun, stmt)) + might throw as well. + ??? We also should care about possible longjmp, but since we + do not understand that longjmp is not using global memory we will + not consider a kill here since the function call will be considered + as possibly using REF. */ + && !stmt_can_throw_internal (cfun, stmt) + && (!stmt_can_throw_external (cfun, stmt) + || !ref_may_alias_global_p (ref, false))) { tree lhs = gimple_get_lhs (stmt); /* If LHS is literally a base of the access we are done. */ @@ -3434,8 +3442,12 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref) && node->binds_to_current_def_p () && (summary = get_modref_function_summary (node)) != NULL && summary->kills.length () + /* Check that we can not trap while evaulating function + parameters. This check is overly conservative. */ && (!cfun->can_throw_non_call_exceptions - || !stmt_can_throw_internal (cfun, stmt))) + || (!stmt_can_throw_internal (cfun, stmt) + && (!stmt_can_throw_external (cfun, stmt) + || !ref_may_alias_global_p (ref, false))))) { for (auto kill : summary->kills) { |