[1/3] tree-ssa-sink: do not sink to in front of setjmp

Message ID 20220114182047.6270-2-amonakov@ispras.ru
State New
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Series
  • [1/3] tree-ssa-sink: do not sink to in front of setjmp
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Commit Message

Antoni Boucher via Gcc-patches Jan. 14, 2022, 6:20 p.m.
gcc/ChangeLog:

	* tree-ssa-sink.c (select_best_block): Punt if selected block
	has incoming abnormal edges.

gcc/testsuite/ChangeLog:

	* gcc.dg/setjmp-7.c: New test.
---
 gcc/testsuite/gcc.dg/setjmp-7.c | 13 +++++++++++++
 gcc/tree-ssa-sink.c             |  6 ++++++
 2 files changed, 19 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/setjmp-7.c

-- 
2.33.1

Comments

Antoni Boucher via Gcc-patches Jan. 17, 2022, 7:47 a.m. | #1
On Fri, Jan 14, 2022 at 7:21 PM Alexander Monakov <amonakov@ispras.ru> wrote:
>

> gcc/ChangeLog:

>

>         * tree-ssa-sink.c (select_best_block): Punt if selected block

>         has incoming abnormal edges.


OK.

> gcc/testsuite/ChangeLog:

>

>         * gcc.dg/setjmp-7.c: New test.

> ---

>  gcc/testsuite/gcc.dg/setjmp-7.c | 13 +++++++++++++

>  gcc/tree-ssa-sink.c             |  6 ++++++

>  2 files changed, 19 insertions(+)

>  create mode 100644 gcc/testsuite/gcc.dg/setjmp-7.c

>

> diff --git a/gcc/testsuite/gcc.dg/setjmp-7.c b/gcc/testsuite/gcc.dg/setjmp-7.c

> new file mode 100644

> index 000000000..44b5bcbfa

> --- /dev/null

> +++ b/gcc/testsuite/gcc.dg/setjmp-7.c

> @@ -0,0 +1,13 @@

> +/* { dg-do compile } */

> +/* { dg-options "-O2 -fno-guess-branch-probability -w" } */

> +/* { dg-require-effective-target indirect_jumps } */

> +

> +struct __jmp_buf_tag { };

> +typedef struct __jmp_buf_tag jmp_buf[1];

> +struct globals { jmp_buf listingbuf; };

> +extern struct globals *const ptr_to_globals;

> +void foo()

> +{

> +    if ( _setjmp ( ((*ptr_to_globals).listingbuf )))

> +       ;

> +}

> diff --git a/gcc/tree-ssa-sink.c b/gcc/tree-ssa-sink.c

> index 66d7ae89e..016ecbaec 100644

> --- a/gcc/tree-ssa-sink.c

> +++ b/gcc/tree-ssa-sink.c

> @@ -208,6 +208,12 @@ select_best_block (basic_block early_bb,

>        temp_bb = get_immediate_dominator (CDI_DOMINATORS, temp_bb);

>      }

>

> +  /* Placing a statement before a setjmp-like function would be invalid

> +     (it cannot be reevaluated when execution follows an abnormal edge).

> +     If we selected a block with abnormal predecessors, just punt.  */

> +  if (bb_has_abnormal_pred (best_bb))

> +    return early_bb;

> +

>    /* If we found a shallower loop nest, then we always consider that

>       a win.  This will always give us the most control dependent block

>       within that loop nest.  */

> --

> 2.33.1

>

Patch

diff --git a/gcc/testsuite/gcc.dg/setjmp-7.c b/gcc/testsuite/gcc.dg/setjmp-7.c
new file mode 100644
index 000000000..44b5bcbfa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/setjmp-7.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-guess-branch-probability -w" } */
+/* { dg-require-effective-target indirect_jumps } */
+
+struct __jmp_buf_tag { };
+typedef struct __jmp_buf_tag jmp_buf[1];
+struct globals { jmp_buf listingbuf; };
+extern struct globals *const ptr_to_globals;
+void foo()
+{
+    if ( _setjmp ( ((*ptr_to_globals).listingbuf )))
+	;
+}
diff --git a/gcc/tree-ssa-sink.c b/gcc/tree-ssa-sink.c
index 66d7ae89e..016ecbaec 100644
--- a/gcc/tree-ssa-sink.c
+++ b/gcc/tree-ssa-sink.c
@@ -208,6 +208,12 @@  select_best_block (basic_block early_bb,
       temp_bb = get_immediate_dominator (CDI_DOMINATORS, temp_bb);
     }
 
+  /* Placing a statement before a setjmp-like function would be invalid
+     (it cannot be reevaluated when execution follows an abnormal edge).
+     If we selected a block with abnormal predecessors, just punt.  */
+  if (bb_has_abnormal_pred (best_bb))
+    return early_bb;
+
   /* If we found a shallower loop nest, then we always consider that
      a win.  This will always give us the most control dependent block
      within that loop nest.  */