On Mon, 27 Feb 2023, Qing Zhao wrote: > Ping.
OK. Thanks, Richard. > Qing > > Begin forwarded message: > > From: Qing Zhao <qing.z...@oracle.com<mailto:qing.z...@oracle.com>> > Subject: [V2][PATCH] Fixing PR107411 > Date: February 21, 2023 at 9:46:04 AM EST > To: ja...@redhat.com<mailto:ja...@redhat.com>, > rguent...@suse.de<mailto:rguent...@suse.de> > Cc: gcc-patches@gcc.gnu.org<mailto:gcc-patches@gcc.gnu.org>, Qing Zhao > <qing.z...@oracle.com<mailto:qing.z...@oracle.com>> > > This is the 2nd version of the patch. > compared to the first version, the major change is: > > use sprintf to replace xasprintf per Jacub's suggestion. > > bootstrapped and regression tested on both x86 and aarch64. > > Okay for committing? > > thanks. > > Qing > > ======================= > > > This is a bug in tree-ssa-uninit.cc<http://tree-ssa-uninit.cc>. > When doing the following: > > /* Ignore the call to .DEFERRED_INIT that define the original > var itself as the following case: > temp = .DEFERRED_INIT (4, 2, “alt_reloc"); > alt_reloc = temp; > In order to avoid generating warning for the fake usage > at alt_reloc = temp. > */ > > We need to compare the var name inside the .DEFERRED_INIT call > (the 3rd argument) and the name for the LHS variable. if they are the same, > we will NOT report the warning. > > There is one issue when we get the name for the LHS variable. when the > variable doesn't have a DECL_NAME (it's not a user declared variable, > which is the case for this bug): > > _1 = .DEFERRED_INIT (4, 2, &"D.2389"[0]); > D.2389 = _1; > > The current checking just ignores this case, and still report the warning. > > The fix is very simple, when getting the name for the LHS variable, we should > consider this case and come up with the name the same way as we construct the > 3rd argument for the call to .DEFERRED_INIT (please refer to the routine > "gimple_add_init_for_auto_var") > > PR middle-end/107411 > > gcc/ChangeLog: > > PR middle-end/107411 > * gimplify.cc<http://gimplify.cc> (gimple_add_init_for_auto_var): Use sprintf > to replace > xasprintf. > * tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> (warn_uninit): Handle the > case when the > LHS varaible of a .DEFERRED_INIT call doesn't have a DECL_NAME. > > gcc/testsuite/ChangeLog: > > PR middle-end/107411 > * g++.dg/pr107411.C: New test. > --- > gcc/gimplify.cc<http://gimplify.cc> | 4 ++-- > gcc/testsuite/g++.dg/pr107411.C | 10 ++++++++++ > gcc/tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> | 23 > ++++++++++++++++------- > 3 files changed, 28 insertions(+), 9 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/pr107411.C > > diff --git a/gcc/gimplify.cc<http://gimplify.cc> > b/gcc/gimplify.cc<http://gimplify.cc> > index 96845154a92..35d1ea22623 100644 > --- a/gcc/gimplify.cc<http://gimplify.cc> > +++ b/gcc/gimplify.cc<http://gimplify.cc> > @@ -1775,9 +1775,9 @@ gimple_add_init_for_auto_var (tree decl, > > else > { > - char *decl_name_anonymous = xasprintf ("D.%u", DECL_UID (decl)); > + char decl_name_anonymous[3 + (HOST_BITS_PER_INT + 2) / 3]; > + sprintf (decl_name_anonymous, "D.%u", DECL_UID (decl)); > decl_name = build_string_literal (decl_name_anonymous); > - free (decl_name_anonymous); > } > > tree call = build_call_expr_internal_loc (loc, IFN_DEFERRED_INIT, > diff --git a/gcc/testsuite/g++.dg/pr107411.C b/gcc/testsuite/g++.dg/pr107411.C > new file mode 100644 > index 00000000000..7eefecae4f3 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/pr107411.C > @@ -0,0 +1,10 @@ > +/* { dg-do compile } */ > +/* { dg-options "-Werror=uninitialized -ftrivial-auto-var-init=zero" } */ > +int t(); > +void f(int); > + > +void j() > +{ > + const int& e = t(); > + f(e); > +} > diff --git a/gcc/tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> > b/gcc/tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> > index c555cf5cd50..9f720ae1f4f 100644 > --- a/gcc/tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> > +++ b/gcc/tree-ssa-uninit.cc<http://tree-ssa-uninit.cc> > @@ -224,8 +224,6 @@ warn_uninit (opt_code opt, tree t, tree var, gimple > *context, > at alt_reloc = temp. > */ > tree lhs_var = NULL_TREE; > - tree lhs_var_name = NULL_TREE; > - const char *lhs_var_name_str = NULL; > > /* Get the variable name from the 3rd argument of call. */ > tree var_name = gimple_call_arg (var_def_stmt, 2); > @@ -239,11 +237,22 @@ warn_uninit (opt_code opt, tree t, tree var, gimple > *context, > else if (TREE_CODE (gimple_assign_lhs (context)) == SSA_NAME) > lhs_var = SSA_NAME_VAR (gimple_assign_lhs (context)); > } > - if (lhs_var > - && (lhs_var_name = DECL_NAME (lhs_var)) > - && (lhs_var_name_str = IDENTIFIER_POINTER (lhs_var_name)) > - && (strcmp (lhs_var_name_str, var_name_str) == 0)) > - return; > + if (lhs_var) > + { > + /* Get the name string for the LHS_VAR. > + Refer to routine gimple_add_init_for_auto_var. */ > + if (DECL_NAME (lhs_var) > + && (strcmp (IDENTIFIER_POINTER (DECL_NAME (lhs_var)), > + var_name_str) == 0)) > + return; > + else if (!DECL_NAME (lhs_var)) > + { > + char lhs_var_name_str_buf[3 + (HOST_BITS_PER_INT + 2) / 3]; > + sprintf (lhs_var_name_str_buf, "D.%u", DECL_UID (lhs_var)); > + if (strcmp (lhs_var_name_str_buf, var_name_str) == 0) > + return; > + } > + } > gcc_assert (var_name_str && var_def_stmt); > } > } > -- > 2.31.1 > > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; HRB 36809 (AG Nuernberg)
