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Diffstat (limited to 'gcc/tree-ssa-operands.c')
| -rw-r--r-- | gcc/tree-ssa-operands.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c index 8e8ef64..26f4963 100644 --- a/gcc/tree-ssa-operands.c +++ b/gcc/tree-ssa-operands.c @@ -1523,13 +1523,23 @@ add_virtual_operand (tree var, stmt_ann_t s_ann, int flags, append_vdef (al); } - /* Even if no aliases have been added, we still need to - establish def-use and use-def chains, lest - transformations think that this is not a memory - reference. For an example of this scenario, see - testsuite/g++.dg/opt/cleanup1.C. */ - if (none_added) - append_vdef (var); + /* If the variable is also an alias tag, add a virtual + operand for it, otherwise we will miss representing + references to the members of the variable's alias set. + This fixes the bug in gcc.c-torture/execute/20020503-1.c. + + It is also necessary to add bare defs on clobbers for + SMT's, so that bare SMT uses caused by pruning all the + aliases will link up properly with calls. In order to + keep the number of these bare defs we add down to the + minimum necessary, we keep track of which SMT's were used + alone in statement vdefs or VUSEs. */ + if (none_added + || (TREE_CODE (var) == SYMBOL_MEMORY_TAG + && is_call_site)) + { + append_vdef (var); + } } else { |