diff options
| -rw-r--r-- | gcc/ipa-modref.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c index e999c2c..90985cc 100644 --- a/gcc/ipa-modref.c +++ b/gcc/ipa-modref.c @@ -1888,19 +1888,18 @@ callee_to_caller_flags (int call_flags, bool ignore_stores, that is not the same as caller returning it. */ call_flags |= EAF_NOT_RETURNED_DIRECTLY | EAF_NOT_RETURNED_INDIRECTLY; - /* TODO: We miss return value propagation. - Be conservative and if value escapes to memory - also mark it as escaping. */ if (!ignore_stores && !(call_flags & EAF_UNUSED)) { + /* If value escapes we are no longer able to track what happens + with it because we can read it from the escaped location + anytime. */ if (!(call_flags & EAF_NO_DIRECT_ESCAPE)) - lattice.merge (~(EAF_NOT_RETURNED_DIRECTLY - | EAF_NOT_RETURNED_INDIRECTLY - | EAF_NO_DIRECT_READ - | EAF_UNUSED)); - if (!(call_flags & EAF_NO_INDIRECT_ESCAPE)) + lattice.merge (0); + else if (!(call_flags & EAF_NO_INDIRECT_ESCAPE)) lattice.merge (~(EAF_NOT_RETURNED_INDIRECTLY | EAF_NO_DIRECT_READ + | EAF_NO_INDIRECT_READ + | EAF_NO_INDIRECT_CLOBBER | EAF_UNUSED)); } else @@ -2036,18 +2035,17 @@ modref_eaf_analysis::analyze_ssa_name (tree name) not_returned and escape has same meaning. However passing arg to return slot is different. If the callee's return slot is returned it means that - arg is written to itself which is an escape. */ + arg is written to itself which is an escape. + Since we do not track the memory it is written to we + need to give up on analysisng it. */ if (!isretslot) { if (!(call_flags & (EAF_NOT_RETURNED_DIRECTLY | EAF_UNUSED))) - m_lattice[index].merge (~(EAF_NO_DIRECT_ESCAPE - | EAF_UNUSED)); - if (!(call_flags & (EAF_NOT_RETURNED_INDIRECTLY - | EAF_UNUSED))) - m_lattice[index].merge (~(EAF_NO_INDIRECT_ESCAPE - | EAF_NO_DIRECT_READ - | EAF_UNUSED)); + m_lattice[index].merge (0); + else gcc_checking_assert + (call_flags & (EAF_NOT_RETURNED_INDIRECTLY + | EAF_UNUSED)); call_flags = callee_to_caller_flags (call_flags, false, m_lattice[index]); |