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| author | Jason Merrill <jason@redhat.com> | 2022-09-20 16:25:42 +0200 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2022-09-29 21:27:02 -0400 |
| commit | 43faf3e5445b571731e52faa1be085ecd0a09323 (patch) | |
| tree | 095d0b528bcb5282e8edd8b950682dc4eddea4b3 | |
| parent | bbdcdf5cc73e1b3385d9a25bdab4df70c4bd8c2e (diff) | |
| download | gcc-43faf3e5445b571731e52faa1be085ecd0a09323.zip gcc-43faf3e5445b571731e52faa1be085ecd0a09323.tar.gz gcc-43faf3e5445b571731e52faa1be085ecd0a09323.tar.bz2 | |
c++: reduce redundant TARGET_EXPR
An experiment led me to notice that in some cases we were ending up with
TARGET_EXPR initialized by TARGET_EXPR, which isn't useful.
The target_expr_needs_replace change won't make a difference in most cases,
since cp_genericize_init will have already expanded VEC_INIT_EXPR by the
time we consider it, but it is correct.
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_fold_r) [TARGET_EXPR]: Collapse
TARGET_EXPR within TARGET_EXPR.
* constexpr.cc (cxx_eval_outermost_constant_expr): Avoid
adding redundant TARGET_EXPR.
* cp-tree.h (target_expr_needs_replace): VEC_INIT_EXPR doesn't.
| -rw-r--r-- | gcc/cp/constexpr.cc | 4 | ||||
| -rw-r--r-- | gcc/cp/cp-gimplify.cc | 16 | ||||
| -rw-r--r-- | gcc/cp/cp-tree.h | 3 |
3 files changed, 17 insertions, 6 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index ed41d75..db7571d 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -8065,8 +8065,8 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_INITIAL (t) == r) return t; - else if (TREE_CODE (t) == CONSTRUCTOR) - ; + else if (TREE_CODE (t) == CONSTRUCTOR || TREE_CODE (t) == CALL_EXPR) + /* Don't add a TARGET_EXPR if our argument didn't have one. */; else if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_CLEANUP (t)) r = get_target_expr (r); else diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc index c05be83..7354888 100644 --- a/gcc/cp/cp-gimplify.cc +++ b/gcc/cp/cp-gimplify.cc @@ -1084,9 +1084,9 @@ cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data_) } break; - /* These are only for genericize time; they're here rather than in - cp_genericize to avoid problems with the invisible reference - transition. */ + /* cp_genericize_{init,target}_expr are only for genericize time; they're + here rather than in cp_genericize to avoid problems with the invisible + reference transition. */ case INIT_EXPR: if (data->genericize) cp_genericize_init_expr (stmt_p); @@ -1095,6 +1095,16 @@ cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data_) case TARGET_EXPR: if (data->genericize) cp_genericize_target_expr (stmt_p); + + /* Folding might replace e.g. a COND_EXPR with a TARGET_EXPR; in + that case, use it in place of this one. */ + if (tree &init = TARGET_EXPR_INITIAL (stmt)) + { + cp_walk_tree (&init, cp_fold_r, data, NULL); + *walk_subtrees = 0; + if (TREE_CODE (init) == TARGET_EXPR) + *stmt_p = init; + } break; default: diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 3cbcdf7..d696fd5 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -5426,7 +5426,8 @@ target_expr_needs_replace (tree t) return false; while (TREE_CODE (init) == COMPOUND_EXPR) init = TREE_OPERAND (init, 1); - return TREE_CODE (init) != AGGR_INIT_EXPR; + return (TREE_CODE (init) != AGGR_INIT_EXPR + && TREE_CODE (init) != VEC_INIT_EXPR); } /* True if EXPR expresses direct-initialization of a TYPE. */ |