diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 59 |
1 files changed, 56 insertions, 3 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index b35dfbf..f1927f2 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -1999,7 +1999,7 @@ fold_convert (tree type, tree arg) return fold (build1 (NOP_EXPR, type, arg)); } else if (VOID_TYPE_P (type)) - return fold (build1 (CONVERT_EXPR, type, arg)); + return fold (build1 (CONVERT_EXPR, type, fold_ignored_result (arg))); abort (); } @@ -2828,7 +2828,7 @@ omit_one_operand (tree type, tree result, tree omitted) tree t = fold_convert (type, result); if (TREE_SIDE_EFFECTS (omitted)) - return build2 (COMPOUND_EXPR, type, omitted, t); + return build2 (COMPOUND_EXPR, type, fold_ignored_result (omitted), t); return non_lvalue (t); } @@ -2841,7 +2841,7 @@ pedantic_omit_one_operand (tree type, tree result, tree omitted) tree t = fold_convert (type, result); if (TREE_SIDE_EFFECTS (omitted)) - return build2 (COMPOUND_EXPR, type, omitted, t); + return build2 (COMPOUND_EXPR, type, fold_ignored_result (omitted), t); return pedantic_non_lvalue (t); } @@ -10583,4 +10583,57 @@ build_fold_indirect_ref (tree t) return build1 (INDIRECT_REF, type, t); } +/* Strip non-trapping, non-side-effecting tree nodes from an expression + whose result is ignored. The type of the returned tree need not be + the same as the original expression. */ + +tree +fold_ignored_result (tree t) +{ + if (!TREE_SIDE_EFFECTS (t)) + return integer_zero_node; + + for (;;) + switch (TREE_CODE_CLASS (TREE_CODE (t))) + { + case '1': + t = TREE_OPERAND (t, 0); + break; + + case '2': + case '<': + if (!TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1))) + t = TREE_OPERAND (t, 0); + else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0))) + t = TREE_OPERAND (t, 1); + else + return t; + break; + + case 'e': + switch (TREE_CODE (t)) + { + case COMPOUND_EXPR: + if (TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1))) + return t; + t = TREE_OPERAND (t, 0); + break; + + case COND_EXPR: + if (TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1)) + || TREE_SIDE_EFFECTS (TREE_OPERAND (t, 2))) + return t; + t = TREE_OPERAND (t, 0); + break; + + default: + return t; + } + break; + + default: + return t; + } +} + #include "gt-fold-const.h" |