On Tue, 8 Nov 2022, Jakub Jelinek wrote:
> On Tue, Nov 08, 2022 at 01:53:48PM +0100, Richard Biener wrote:
> > The following makes sure to set alignment information on the LHS
> > of __builtin_assume_alignment calls even when not optimizing so
> > uses as arguments to builtin functions like memcpy or __atomic_load_n
> > can be reflected at RTL expansion time.
> >
> > Bootstrap and regtest running on x86_64-unknown-linux-gnu, OK?
> >
> > Thanks,
> > Richard.
> >
> > PR tree-optimization/107389
> > * gimple-low.cc (lower_builtin_assume_aligned): New.
> > (lower_stmt): Call it.
> >
> > * gcc.dg/pr107389.c: New testcase.
> > ---
> > gcc/gimple-low.cc | 41 +++++++++++++++++++++++++++++++++
> > gcc/testsuite/gcc.dg/pr107389.c | 13 +++++++++++
> > 2 files changed, 54 insertions(+)
> > create mode 100644 gcc/testsuite/gcc.dg/pr107389.c
> >
> > diff --git a/gcc/gimple-low.cc b/gcc/gimple-low.cc
> > index 512aa9feada..f9bcb772163 100644
> > --- a/gcc/gimple-low.cc
> > +++ b/gcc/gimple-low.cc
> > @@ -84,6 +84,7 @@ static void lower_try_catch (gimple_stmt_iterator *,
> > struct lower_data *);
> > static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data
> > *);
> > static void lower_builtin_setjmp (gimple_stmt_iterator *);
> > static void lower_builtin_posix_memalign (gimple_stmt_iterator *);
> > +static void lower_builtin_assume_aligned (gimple_stmt_iterator *);
> >
> >
> > /* Lower the body of current_function_decl from High GIMPLE into Low
> > @@ -768,6 +769,13 @@ lower_stmt (gimple_stmt_iterator *gsi, struct
> > lower_data *data)
> > lower_builtin_posix_memalign (gsi);
> > return;
> > }
> > + else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_ASSUME_ALIGNED
> > + && !optimize)
> > + {
> > + lower_builtin_assume_aligned (gsi);
> > + data->cannot_fallthru = false;
> > + return;
> > + }
> > }
> >
> > if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN))
> > @@ -1310,6 +1318,39 @@ lower_builtin_posix_memalign (gimple_stmt_iterator
> > *gsi)
> > gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
> > gsi_insert_after (gsi, gimple_build_label (noalign_label), GSI_NEW_STMT);
> > }
> > +
> > +/* Lower calls to __builtin_assume_aligned when not optimizing. */
> > +
> > +static void
> > +lower_builtin_assume_aligned (gimple_stmt_iterator *gsi)
> > +{
> > + gcall *call = as_a <gcall *> (gsi_stmt (*gsi));
> > +
> > + tree lhs = gimple_call_lhs (call);
> > + if (!lhs || !POINTER_TYPE_P (TREE_TYPE (lhs)))
> > + return;
>
> I think nothing checks that TREE_CODE (lhs) == SSA_NAME,
> that isn't guaranteed before ssa pass.
Yep, noticed in the testsuite and fixed.
Richard.
