diff mbox series

lower-bitint: Fix up handling of uninitialized large/huge _BitInt call arguments [PR113316]

Message ID ZaEHikflGhduPrnv@tucnak
State Unresolved
Headers
Series lower-bitint: Fix up handling of uninitialized large/huge _BitInt call arguments [PR113316] |

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Context Check Description
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Commit Message

Jakub Jelinek Jan. 12, 2024, 9:34 a.m. UTC 
  Hi!

The code to assign large/huge _BitInt SSA_NAMEs to partitions intentionally
ignores uninitialized SSA_NAMEs:
          /* Also ignore uninitialized uses.  */
          if (SSA_NAME_IS_DEFAULT_DEF (s)
              && (!SSA_NAME_VAR (s) || VAR_P (SSA_NAME_VAR (s))))
            continue;
because there is no need to store them into memory, all we need is when
trying to extract some limb from them use uninitialized SSA_NAME for the
limb.

The following testcase shows this is a problem for call arguments though,
for those we need to create replacement SSA_NAMEs which are loaded from
the underlying variable.  For uninitialized SSA_NAMEs because we didn't
create underlying variable for them var_to_partition doesn't work, the
following patch handles it by just creating an uninitialized replacement
SSA_NAME.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2024-01-12  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/113316
	* gimple-lower-bitint.cc (bitint_large_huge::lower_call): Handle
	uninitialized large/huge _BitInt arguments to calls.

	* gcc.dg/bitint-67.c: New test.


	Jakub

Comments

Richard Biener Jan. 12, 2024, 9:43 a.m. UTC | #1 
On Fri, 12 Jan 2024, Jakub Jelinek wrote:

> Hi!
> 
> The code to assign large/huge _BitInt SSA_NAMEs to partitions intentionally
> ignores uninitialized SSA_NAMEs:
>           /* Also ignore uninitialized uses.  */
>           if (SSA_NAME_IS_DEFAULT_DEF (s)
>               && (!SSA_NAME_VAR (s) || VAR_P (SSA_NAME_VAR (s))))
>             continue;
> because there is no need to store them into memory, all we need is when
> trying to extract some limb from them use uninitialized SSA_NAME for the
> limb.
> 
> The following testcase shows this is a problem for call arguments though,
> for those we need to create replacement SSA_NAMEs which are loaded from
> the underlying variable.  For uninitialized SSA_NAMEs because we didn't
> create underlying variable for them var_to_partition doesn't work, the
> following patch handles it by just creating an uninitialized replacement
> SSA_NAME.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK

> 2024-01-12  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR tree-optimization/113316
> 	* gimple-lower-bitint.cc (bitint_large_huge::lower_call): Handle
> 	uninitialized large/huge _BitInt arguments to calls.
> 
> 	* gcc.dg/bitint-67.c: New test.
> 
> --- gcc/gimple-lower-bitint.cc.jj	2024-01-11 11:46:49.147779946 +0100
> +++ gcc/gimple-lower-bitint.cc	2024-01-11 13:52:46.106182653 +0100
> @@ -5118,14 +5118,23 @@ bitint_large_huge::lower_call (tree obj,
>  	  || TREE_CODE (TREE_TYPE (arg)) != BITINT_TYPE
>  	  || bitint_precision_kind (TREE_TYPE (arg)) <= bitint_prec_middle)
>  	continue;
> -      int p = var_to_partition (m_map, arg);
> -      tree v = m_vars[p];
> -      gcc_assert (v != NULL_TREE);
> -      if (!types_compatible_p (TREE_TYPE (arg), TREE_TYPE (v)))
> -	v = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (arg), v);
> -      arg = make_ssa_name (TREE_TYPE (arg));
> -      gimple *g = gimple_build_assign (arg, v);
> -      gsi_insert_before (&gsi, g, GSI_SAME_STMT);
> +      if (SSA_NAME_IS_DEFAULT_DEF (arg)
> +	  && (!SSA_NAME_VAR (arg) || VAR_P (SSA_NAME_VAR (arg))))
> +	{
> +	  tree var = create_tmp_reg (TREE_TYPE (arg));
> +	  arg = get_or_create_ssa_default_def (cfun, var);
> +	}
> +      else
> +	{
> +	  int p = var_to_partition (m_map, arg);
> +	  tree v = m_vars[p];
> +	  gcc_assert (v != NULL_TREE);
> +	  if (!types_compatible_p (TREE_TYPE (arg), TREE_TYPE (v)))
> +	    v = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (arg), v);
> +	  arg = make_ssa_name (TREE_TYPE (arg));
> +	  gimple *g = gimple_build_assign (arg, v);
> +	  gsi_insert_before (&gsi, g, GSI_SAME_STMT);
> +	}
>        gimple_call_set_arg (stmt, i, arg);
>        if (m_preserved == NULL)
>  	m_preserved = BITMAP_ALLOC (NULL);
> --- gcc/testsuite/gcc.dg/bitint-67.c.jj	2024-01-11 13:54:14.561936065 +0100
> +++ gcc/testsuite/gcc.dg/bitint-67.c	2024-01-11 13:55:09.474162196 +0100
> @@ -0,0 +1,12 @@
> +/* PR tree-optimization/113316 */
> +/* { dg-do compile { target bitint575 } } */
> +/* { dg-options "-std=c23 -O2 -w" } */
> +
> +void bar (_BitInt(535) y);
> +
> +void
> +foo (void)
> +{
> +  _BitInt(535) y;
> +  bar (y);
> +}
> 
> 	Jakub
> 
>
diff mbox series

Patch

--- gcc/gimple-lower-bitint.cc.jj	2024-01-11 11:46:49.147779946 +0100
+++ gcc/gimple-lower-bitint.cc	2024-01-11 13:52:46.106182653 +0100
@@ -5118,14 +5118,23 @@  bitint_large_huge::lower_call (tree obj,
 	  || TREE_CODE (TREE_TYPE (arg)) != BITINT_TYPE
 	  || bitint_precision_kind (TREE_TYPE (arg)) <= bitint_prec_middle)
 	continue;
-      int p = var_to_partition (m_map, arg);
-      tree v = m_vars[p];
-      gcc_assert (v != NULL_TREE);
-      if (!types_compatible_p (TREE_TYPE (arg), TREE_TYPE (v)))
-	v = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (arg), v);
-      arg = make_ssa_name (TREE_TYPE (arg));
-      gimple *g = gimple_build_assign (arg, v);
-      gsi_insert_before (&gsi, g, GSI_SAME_STMT);
+      if (SSA_NAME_IS_DEFAULT_DEF (arg)
+	  && (!SSA_NAME_VAR (arg) || VAR_P (SSA_NAME_VAR (arg))))
+	{
+	  tree var = create_tmp_reg (TREE_TYPE (arg));
+	  arg = get_or_create_ssa_default_def (cfun, var);
+	}
+      else
+	{
+	  int p = var_to_partition (m_map, arg);
+	  tree v = m_vars[p];
+	  gcc_assert (v != NULL_TREE);
+	  if (!types_compatible_p (TREE_TYPE (arg), TREE_TYPE (v)))
+	    v = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (arg), v);
+	  arg = make_ssa_name (TREE_TYPE (arg));
+	  gimple *g = gimple_build_assign (arg, v);
+	  gsi_insert_before (&gsi, g, GSI_SAME_STMT);
+	}
       gimple_call_set_arg (stmt, i, arg);
       if (m_preserved == NULL)
 	m_preserved = BITMAP_ALLOC (NULL);
--- gcc/testsuite/gcc.dg/bitint-67.c.jj	2024-01-11 13:54:14.561936065 +0100
+++ gcc/testsuite/gcc.dg/bitint-67.c	2024-01-11 13:55:09.474162196 +0100
@@ -0,0 +1,12 @@ 
+/* PR tree-optimization/113316 */
+/* { dg-do compile { target bitint575 } } */
+/* { dg-options "-std=c23 -O2 -w" } */
+
+void bar (_BitInt(535) y);
+
+void
+foo (void)
+{
+  _BitInt(535) y;
+  bar (y);
+}