i386: Fix ICE on __builtin_ia32_pabsd128 without lhs [PR112962]

Message ID ZXlu12NJxQVbvYfG@tucnak
State Unresolved
Headers
Series i386: Fix ICE on __builtin_ia32_pabsd128 without lhs [PR112962] |

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Commit Message

Jakub Jelinek Dec. 13, 2023, 8:44 a.m. UTC
  Hi!

The following patch fixes ICE on the testcase in similar way to how
other folded builtins are handled in ix86_gimple_fold_builtin when
they don't have a lhs; these builtins are const or pure, so normally
DCE would remove them later, but with -O0 that isn't guaranteed to
happen, and during expansion if they are marked TREE_SIDE_EFFECTS
it might still be attempted to be expanded.
This removes them right away during the folding.

Initially I wanted to also change all gsi_replace last args in that function
to true, but Andrew pointed to PR107209, so I've kept them as is.

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

2023-12-13  Jakub Jelinek  <jakub@redhat.com>

	PR target/112962
	* config/i386/i386.cc (ix86_gimple_fold_builtin): For shifts
	and abs without lhs replace with nop.

	* gcc.target/i386/pr112962.c: New test.


	Jakub
  

Comments

Hongtao Liu Dec. 13, 2023, 8:46 a.m. UTC | #1
On Wed, Dec 13, 2023 at 4:44 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> Hi!
>
> The following patch fixes ICE on the testcase in similar way to how
> other folded builtins are handled in ix86_gimple_fold_builtin when
> they don't have a lhs; these builtins are const or pure, so normally
> DCE would remove them later, but with -O0 that isn't guaranteed to
> happen, and during expansion if they are marked TREE_SIDE_EFFECTS
> it might still be attempted to be expanded.
> This removes them right away during the folding.
>
> Initially I wanted to also change all gsi_replace last args in that function
> to true, but Andrew pointed to PR107209, so I've kept them as is.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
>
> 2023-12-13  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/112962
>         * config/i386/i386.cc (ix86_gimple_fold_builtin): For shifts
>         and abs without lhs replace with nop.
>
>         * gcc.target/i386/pr112962.c: New test.
>
> --- gcc/config/i386/i386.cc.jj  2023-12-12 13:06:05.864509295 +0100
> +++ gcc/config/i386/i386.cc     2023-12-13 00:02:28.543600557 +0100
> @@ -19377,7 +19377,10 @@ ix86_gimple_fold_builtin (gimple_stmt_it
>      do_shift:
>        gcc_assert (n_args >= 2);
>        if (!gimple_call_lhs (stmt))
> -       break;
> +       {
> +         gsi_replace (gsi, gimple_build_nop (), false);
> +         return true;
> +       }
>        arg0 = gimple_call_arg (stmt, 0);
>        arg1 = gimple_call_arg (stmt, 1);
>        elems = TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0));
> @@ -19523,7 +19526,10 @@ ix86_gimple_fold_builtin (gimple_stmt_it
>      case IX86_BUILTIN_PABSD256_MASK:
>        gcc_assert (n_args >= 1);
>        if (!gimple_call_lhs (stmt))
> -       break;
> +       {
> +         gsi_replace (gsi, gimple_build_nop (), false);
> +         return true;
> +       }
>        arg0 = gimple_call_arg (stmt, 0);
>        elems = TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0));
>        /* For masked ABS, only optimize if the mask is all ones.  */
> --- gcc/testsuite/gcc.target/i386/pr112962.c.jj 2023-12-12 11:56:56.735917531 +0100
> +++ gcc/testsuite/gcc.target/i386/pr112962.c    2023-12-12 11:56:39.406157222 +0100
> @@ -0,0 +1,11 @@
> +/* PR target/112962 */
> +/* { dg-do compile } */
> +/* { dg-options "-fexceptions -mssse3" } */
> +
> +typedef int __attribute__((__vector_size__ (16))) V;
> +
> +void
> +foo (void)
> +{
> +  __builtin_ia32_pabsd128 ((V) {});
> +}
>
>         Jakub
>
  

Patch

--- gcc/config/i386/i386.cc.jj	2023-12-12 13:06:05.864509295 +0100
+++ gcc/config/i386/i386.cc	2023-12-13 00:02:28.543600557 +0100
@@ -19377,7 +19377,10 @@  ix86_gimple_fold_builtin (gimple_stmt_it
     do_shift:
       gcc_assert (n_args >= 2);
       if (!gimple_call_lhs (stmt))
-	break;
+	{
+	  gsi_replace (gsi, gimple_build_nop (), false);
+	  return true;
+	}
       arg0 = gimple_call_arg (stmt, 0);
       arg1 = gimple_call_arg (stmt, 1);
       elems = TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0));
@@ -19523,7 +19526,10 @@  ix86_gimple_fold_builtin (gimple_stmt_it
     case IX86_BUILTIN_PABSD256_MASK:
       gcc_assert (n_args >= 1);
       if (!gimple_call_lhs (stmt))
-	break;
+	{
+	  gsi_replace (gsi, gimple_build_nop (), false);
+	  return true;
+	}
       arg0 = gimple_call_arg (stmt, 0);
       elems = TYPE_VECTOR_SUBPARTS (TREE_TYPE (arg0));
       /* For masked ABS, only optimize if the mask is all ones.  */
--- gcc/testsuite/gcc.target/i386/pr112962.c.jj	2023-12-12 11:56:56.735917531 +0100
+++ gcc/testsuite/gcc.target/i386/pr112962.c	2023-12-12 11:56:39.406157222 +0100
@@ -0,0 +1,11 @@ 
+/* PR target/112962 */
+/* { dg-do compile } */
+/* { dg-options "-fexceptions -mssse3" } */
+
+typedef int __attribute__((__vector_size__ (16))) V;
+
+void
+foo (void)
+{
+  __builtin_ia32_pabsd128 ((V) {});
+}