On Tue, Jul 24, 2018 at 01:37:32PM +0200, Tom de Vries wrote:
> Another drawback is that the fake uses confuse the unitialized warning
> analysis, so that is switched off for -fkeep-vars-live.
Is that really needed? I.e. can't you for the purpose of uninitialized
warning analysis ignore the clobber = var uses?
Is the -fkeep-vars-live option -fcompare-debug friendly?
> --- a/gcc/cfgexpand.c
> +++ b/gcc/cfgexpand.c
> @@ -3533,6 +3533,13 @@ expand_clobber (tree lhs)
> }
> }
>
> +static void
> +expand_use (tree rhs)
> +{
> + rtx target = expand_expr (rhs, NULL_RTX, VOIDmode, EXPAND_NORMAL);
> + emit_use (target);
> +}
Missing function comment.
> +fkeep-vars-live
> +Common Report Var(flag_keep_vars_live) Optimization
> +Add artificial uses of local vars at end of scope.
at the end of scope?
> --- a/gcc/gimplify.c
> +++ b/gcc/gimplify.c
> @@ -1264,6 +1264,23 @@ asan_poison_variables (hash_set<tree> *variables, bool
> poison, gimple_seq *seq_p
> }
> }
>
> +static gimple_seq
> +gimple_build_uses (tree vars)
Missing function comment.
> --- a/gcc/tree-ssa-alias.c
> +++ b/gcc/tree-ssa-alias.c
> @@ -1368,6 +1368,10 @@ refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool
> tbaa_p)
> poly_int64 max_size1 = -1, max_size2 = -1;
> bool var1_p, var2_p, ind1_p, ind2_p;
>
> + if ((ref1->ref && TREE_CLOBBER_P (ref1->ref)) ||
|| should go on the next line.
> + (ref2->ref && TREE_CLOBBER_P (ref2->ref)))
> + return false;
> +
> gcc_checking_assert ((!ref1->ref
> || TREE_CODE (ref1->ref) == SSA_NAME
> || DECL_P (ref1->ref)
> --- a/gcc/tree-ssa-uninit.c
> +++ b/gcc/tree-ssa-uninit.c
> @@ -2628,7 +2628,7 @@ warn_uninitialized_phi (gphi *phi, vec<gphi *>
> *worklist,
> static bool
> gate_warn_uninitialized (void)
> {
> - return warn_uninitialized || warn_maybe_uninitialized;
> + return (warn_uninitialized || warn_maybe_uninitialized) &&
> !flag_keep_vars_live;
> }
See above.
Jakub
