Re: [PATCH] bitint, v2: Fix up adjustment of large/huge _BitInt arguments of returns_twice calls [PR113466]
On Thu, 14 Mar 2024, Jakub Jelinek wrote:
> On Thu, Mar 14, 2024 at 09:59:12AM +0100, Richard Biener wrote:
> > On Thu, 14 Mar 2024, Jakub Jelinek wrote:
> >
> > > On Thu, Mar 14, 2024 at 09:48:45AM +0100, Richard Biener wrote:
> > > > Ugh. OK, but I wonder whether we might want to simply delay
> > > > fixing the CFG for inserts before returns-twice? Would that make
> > > > things less ugly?
> > >
> > > You mean in lower_call just remember if we added anything before
> > > ECF_RETURNS_TWICE call (or say add such stmt into a vector) and
> > > then fix it up before the end of the pass?
> >
> > Yeah, or just walk BBs with abnormal preds, whatever tracking is
> > easier.
>
> Walking all the bbs with abnormal preds would mean I'd have to walk their
> whole bodies, because the ECF_RETURNS_TWICE call is no longer at the start.
>
> The following patch seems to work, ok for trunk if it passes full
> bootstrap/regtest?
OK. I'll let you decide which variant is better maintainable
(I think this one).
Thanks,
Richard.
> 2024-03-14 Jakub Jelinek
>
> PR tree-optimization/113466
> * gimple-lower-bitint.cc (bitint_large_huge): Add m_returns_twice_calls
> member.
> (bitint_large_huge::bitint_large_huge): Initialize it.
> (bitint_large_huge::~bitint_large_huge): Release it.
> (bitint_large_huge::lower_call): Remember ECF_RETURNS_TWICE call stmts
> before which at least one statement has been inserted.
> (gimple_lower_bitint): Move argument loads before ECF_RETURNS_TWICE
> calls to a different block and add corresponding PHIs.
>
> * gcc.dg/bitint-100.c: New test.
>
> --- gcc/gimple-lower-bitint.cc.jj 2024-03-13 15:34:29.969725763 +0100
> +++ gcc/gimple-lower-bitint.cc2024-03-14 11:25:07.763169074 +0100
> @@ -419,7 +419,8 @@ struct bitint_large_huge
>bitint_large_huge ()
> : m_names (NULL), m_loads (NULL), m_preserved (NULL),
>m_single_use_names (NULL), m_map (NULL), m_vars (NULL),
> - m_limb_type (NULL_TREE), m_data (vNULL) {}
> + m_limb_type (NULL_TREE), m_data (vNULL),
> + m_returns_twice_calls (vNULL) {}
>
>~bitint_large_huge ();
>
> @@ -553,6 +554,7 @@ struct bitint_large_huge
>unsigned m_bitfld_load;
>vec m_data;
>unsigned int m_data_cnt;
> + vec m_returns_twice_calls;
> };
>
> bitint_large_huge::~bitint_large_huge ()
> @@ -565,6 +567,7 @@ bitint_large_huge::~bitint_large_huge ()
> delete_var_map (m_map);
>XDELETEVEC (m_vars);
>m_data.release ();
> + m_returns_twice_calls.release ();
> }
>
> /* Insert gimple statement G before current location
> @@ -5248,6 +5251,7 @@ bitint_large_huge::lower_call (tree obj,
>default:
> break;
>}
> + bool returns_twice = (gimple_call_flags (stmt) & ECF_RETURNS_TWICE) != 0;
>for (unsigned int i = 0; i < nargs; ++i)
> {
>tree arg = gimple_call_arg (stmt, i);
> @@ -5271,6 +5275,11 @@ bitint_large_huge::lower_call (tree obj,
> arg = make_ssa_name (TREE_TYPE (arg));
> gimple *g = gimple_build_assign (arg, v);
> gsi_insert_before (, g, GSI_SAME_STMT);
> + if (returns_twice)
> + {
> + m_returns_twice_calls.safe_push (stmt);
> + returns_twice = false;
> + }
> }
>gimple_call_set_arg (stmt, i, arg);
>if (m_preserved == NULL)
> @@ -7091,6 +7100,66 @@ gimple_lower_bitint (void)
>if (edge_insertions)
> gsi_commit_edge_inserts ();
>
> + /* Fix up arguments of ECF_RETURNS_TWICE calls. Those were temporarily
> + inserted before the call, but that is invalid IL, so move them to the
> + right place and add corresponding PHIs. */
> + if (!large_huge.m_returns_twice_calls.is_empty ())
> +{
> + auto_vec arg_stmts;
> + while (!large_huge.m_returns_twice_calls.is_empty ())
> + {
> + gimple *stmt = large_huge.m_returns_twice_calls.pop ();
> + gimple_stmt_iterator gsi = gsi_after_labels (gimple_bb (stmt));
> + while (gsi_stmt (gsi) != stmt)
> + {
> + arg_stmts.safe_push (gsi_stmt (gsi));
> + gsi_remove (, false);
> + }
> + gimple *g;
> + basic_block bb = NULL;
> + edge e = NULL, ead = NULL;
> + FOR_EACH_VEC_ELT (arg_stmts, i, g)
> + {
> + gsi_safe_insert_before (, g);
> + if (i == 0)
> + {
> + bb = gimple_bb (stmt);
> + gcc_checking_assert (EDGE_COUNT (bb->preds) == 2);
> + e = EDGE_PRED (bb, 0);
> + ead = EDGE_PRED (bb, 1);
> + if ((ead->flags & EDGE_ABNORMAL) == 0)
> + std::swap (e, ead);
> + gcc_checking_assert ((e->flags & EDGE_ABNORMAL) == 0
> +&& (ead->flags & EDGE_ABNORMAL));
> + }
> + tree lhs = gimple_assign_lhs (g);
> + tree arg = lhs;
> + gphi *phi = create_phi_node (copy_ssa_name
[PATCH] bitint, v2: Fix up adjustment of large/huge _BitInt arguments of returns_twice calls [PR113466]
On Thu, Mar 14, 2024 at 09:59:12AM +0100, Richard Biener wrote:
> On Thu, 14 Mar 2024, Jakub Jelinek wrote:
>
> > On Thu, Mar 14, 2024 at 09:48:45AM +0100, Richard Biener wrote:
> > > Ugh. OK, but I wonder whether we might want to simply delay
> > > fixing the CFG for inserts before returns-twice? Would that make
> > > things less ugly?
> >
> > You mean in lower_call just remember if we added anything before
> > ECF_RETURNS_TWICE call (or say add such stmt into a vector) and
> > then fix it up before the end of the pass?
>
> Yeah, or just walk BBs with abnormal preds, whatever tracking is
> easier.
Walking all the bbs with abnormal preds would mean I'd have to walk their
whole bodies, because the ECF_RETURNS_TWICE call is no longer at the start.
The following patch seems to work, ok for trunk if it passes full
bootstrap/regtest?
2024-03-14 Jakub Jelinek
PR tree-optimization/113466
* gimple-lower-bitint.cc (bitint_large_huge): Add m_returns_twice_calls
member.
(bitint_large_huge::bitint_large_huge): Initialize it.
(bitint_large_huge::~bitint_large_huge): Release it.
(bitint_large_huge::lower_call): Remember ECF_RETURNS_TWICE call stmts
before which at least one statement has been inserted.
(gimple_lower_bitint): Move argument loads before ECF_RETURNS_TWICE
calls to a different block and add corresponding PHIs.
* gcc.dg/bitint-100.c: New test.
--- gcc/gimple-lower-bitint.cc.jj 2024-03-13 15:34:29.969725763 +0100
+++ gcc/gimple-lower-bitint.cc 2024-03-14 11:25:07.763169074 +0100
@@ -419,7 +419,8 @@ struct bitint_large_huge
bitint_large_huge ()
: m_names (NULL), m_loads (NULL), m_preserved (NULL),
m_single_use_names (NULL), m_map (NULL), m_vars (NULL),
- m_limb_type (NULL_TREE), m_data (vNULL) {}
+ m_limb_type (NULL_TREE), m_data (vNULL),
+ m_returns_twice_calls (vNULL) {}
~bitint_large_huge ();
@@ -553,6 +554,7 @@ struct bitint_large_huge
unsigned m_bitfld_load;
vec m_data;
unsigned int m_data_cnt;
+ vec m_returns_twice_calls;
};
bitint_large_huge::~bitint_large_huge ()
@@ -565,6 +567,7 @@ bitint_large_huge::~bitint_large_huge ()
delete_var_map (m_map);
XDELETEVEC (m_vars);
m_data.release ();
+ m_returns_twice_calls.release ();
}
/* Insert gimple statement G before current location
@@ -5248,6 +5251,7 @@ bitint_large_huge::lower_call (tree obj,
default:
break;
}
+ bool returns_twice = (gimple_call_flags (stmt) & ECF_RETURNS_TWICE) != 0;
for (unsigned int i = 0; i < nargs; ++i)
{
tree arg = gimple_call_arg (stmt, i);
@@ -5271,6 +5275,11 @@ bitint_large_huge::lower_call (tree obj,
arg = make_ssa_name (TREE_TYPE (arg));
gimple *g = gimple_build_assign (arg, v);
gsi_insert_before (, g, GSI_SAME_STMT);
+ if (returns_twice)
+ {
+ m_returns_twice_calls.safe_push (stmt);
+ returns_twice = false;
+ }
}
gimple_call_set_arg (stmt, i, arg);
if (m_preserved == NULL)
@@ -7091,6 +7100,66 @@ gimple_lower_bitint (void)
if (edge_insertions)
gsi_commit_edge_inserts ();
+ /* Fix up arguments of ECF_RETURNS_TWICE calls. Those were temporarily
+ inserted before the call, but that is invalid IL, so move them to the
+ right place and add corresponding PHIs. */
+ if (!large_huge.m_returns_twice_calls.is_empty ())
+{
+ auto_vec arg_stmts;
+ while (!large_huge.m_returns_twice_calls.is_empty ())
+ {
+ gimple *stmt = large_huge.m_returns_twice_calls.pop ();
+ gimple_stmt_iterator gsi = gsi_after_labels (gimple_bb (stmt));
+ while (gsi_stmt (gsi) != stmt)
+ {
+ arg_stmts.safe_push (gsi_stmt (gsi));
+ gsi_remove (, false);
+ }
+ gimple *g;
+ basic_block bb = NULL;
+ edge e = NULL, ead = NULL;
+ FOR_EACH_VEC_ELT (arg_stmts, i, g)
+ {
+ gsi_safe_insert_before (, g);
+ if (i == 0)
+ {
+ bb = gimple_bb (stmt);
+ gcc_checking_assert (EDGE_COUNT (bb->preds) == 2);
+ e = EDGE_PRED (bb, 0);
+ ead = EDGE_PRED (bb, 1);
+ if ((ead->flags & EDGE_ABNORMAL) == 0)
+ std::swap (e, ead);
+ gcc_checking_assert ((e->flags & EDGE_ABNORMAL) == 0
+ && (ead->flags & EDGE_ABNORMAL));
+ }
+ tree lhs = gimple_assign_lhs (g);
+ tree arg = lhs;
+ gphi *phi = create_phi_node (copy_ssa_name (arg), bb);
+ add_phi_arg (phi, arg, e, UNKNOWN_LOCATION);
+ tree var = create_tmp_reg (TREE_TYPE (arg));
+ suppress_warning (var, OPT_Wuninitialized);
+ arg = get_or_create_ssa_default_def (cfun, var);
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI
