* Re: [PATCH] tree-optimization/106722 - fix CD-DCE edge marking
[not found] <20230210101245.1440C385B514@sourceware.org>
@ 2023-02-13 14:42 ` Jeff Law
0 siblings, 0 replies; 3+ messages in thread
From: Jeff Law @ 2023-02-13 14:42 UTC (permalink / raw)
To: Richard Biener, gcc-patches; +Cc: Jan Hubicka
On 2/10/23 03:12, Richard Biener via Gcc-patches wrote:
> The following fixes a latent issue when we mark control edges but
> end up with marking a block with no stmts necessary. In this case
> we fail to mark dependent control edges of that block.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> Does this look OK?
>
> Thanks,
> Richard.
>
> PR tree-optimization/106722
> * tree-ssa-dce.cc (mark_last_stmt_necessary): Return
> whether we marked a stmt.
> (mark_control_dependent_edges_necessary): When
> mark_last_stmt_necessary didn't mark any stmt make sure
> to mark its control dependent edges.
> (propagate_necessity): Likewise.
>
> * gcc.dg/torture/pr108737.c: New testcase.
> diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
> index b2fe9f4f55e..21b3294fc86 100644
> --- a/gcc/tree-ssa-dce.cc
> +++ b/gcc/tree-ssa-dce.cc
> @@ -327,17 +327,23 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool aggressive)
>
> /* Mark the last statement of BB as necessary. */
>
> -static void
> +static bool
Function comment probably needs an update for the new return value.
OK with that fix.
jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tree-optimization/106722 - fix CD-DCE edge marking
@ 2023-02-10 21:16 Jan Hubicka
0 siblings, 0 replies; 3+ messages in thread
From: Jan Hubicka @ 2023-02-10 21:16 UTC (permalink / raw)
To: Richard Biener; +Cc: gcc-patches
> The following fixes a latent issue when we mark control edges but
> end up with marking a block with no stmts necessary. In this case
> we fail to mark dependent control edges of that block.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> Does this look OK?
>
> Thanks,
> Richard.
>
> PR tree-optimization/106722
> * tree-ssa-dce.cc (mark_last_stmt_necessary): Return
> whether we marked a stmt.
> (mark_control_dependent_edges_necessary): When
> mark_last_stmt_necessary didn't mark any stmt make sure
> to mark its control dependent edges.
> (propagate_necessity): Likewise.
>
> * gcc.dg/torture/pr108737.c: New testcase.
> diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
> index b2fe9f4f55e..21b3294fc86 100644
> --- a/gcc/tree-ssa-dce.cc
> +++ b/gcc/tree-ssa-dce.cc
> @@ -327,17 +327,23 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool aggressive)
>
> /* Mark the last statement of BB as necessary. */
>
> -static void
> +static bool
> mark_last_stmt_necessary (basic_block bb)
> {
> gimple *stmt = last_stmt (bb);
>
> - bitmap_set_bit (last_stmt_necessary, bb->index);
> + if (!bitmap_set_bit (last_stmt_necessary, bb->index))
> + return true;
> +
> bitmap_set_bit (bb_contains_live_stmts, bb->index);
>
> /* We actually mark the statement only if it is a control statement. */
> if (stmt && is_ctrl_stmt (stmt))
> - mark_stmt_necessary (stmt, true);
> + {
> + mark_stmt_necessary (stmt, true);
> + return true;
> + }
> + return false;
> }
>
>
> @@ -369,8 +375,8 @@ mark_control_dependent_edges_necessary (basic_block bb, bool ignore_self)
> continue;
> }
>
> - if (!bitmap_bit_p (last_stmt_necessary, cd_bb->index))
> - mark_last_stmt_necessary (cd_bb);
> + if (!mark_last_stmt_necessary (cd_bb))
> + mark_control_dependent_edges_necessary (cd_bb, false);
Makes sense to me, though I am bit surprised it took such a long time to
show up.
Honza
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] tree-optimization/106722 - fix CD-DCE edge marking
@ 2023-02-10 10:12 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2023-02-10 10:12 UTC (permalink / raw)
To: gcc-patches; +Cc: Jan Hubicka
The following fixes a latent issue when we mark control edges but
end up with marking a block with no stmts necessary. In this case
we fail to mark dependent control edges of that block.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Does this look OK?
Thanks,
Richard.
PR tree-optimization/106722
* tree-ssa-dce.cc (mark_last_stmt_necessary): Return
whether we marked a stmt.
(mark_control_dependent_edges_necessary): When
mark_last_stmt_necessary didn't mark any stmt make sure
to mark its control dependent edges.
(propagate_necessity): Likewise.
* gcc.dg/torture/pr108737.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr108737.c | 19 +++++++++++++++++++
gcc/tree-ssa-dce.cc | 20 +++++++++++++-------
2 files changed, 32 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr108737.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr108737.c b/gcc/testsuite/gcc.dg/torture/pr108737.c
new file mode 100644
index 00000000000..c8388bcabeb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr108737.c
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+
+extern void exit (int);
+extern void abort (void);
+
+void __attribute__((noipa)) foo () { exit (0); }
+
+void __attribute__((noipa)) blah (int x)
+{
+ while (1) {
+ if(x) foo();
+ }
+}
+
+int main()
+{
+ blah (1);
+ abort ();
+}
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index b2fe9f4f55e..21b3294fc86 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -327,17 +327,23 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool aggressive)
/* Mark the last statement of BB as necessary. */
-static void
+static bool
mark_last_stmt_necessary (basic_block bb)
{
gimple *stmt = last_stmt (bb);
- bitmap_set_bit (last_stmt_necessary, bb->index);
+ if (!bitmap_set_bit (last_stmt_necessary, bb->index))
+ return true;
+
bitmap_set_bit (bb_contains_live_stmts, bb->index);
/* We actually mark the statement only if it is a control statement. */
if (stmt && is_ctrl_stmt (stmt))
- mark_stmt_necessary (stmt, true);
+ {
+ mark_stmt_necessary (stmt, true);
+ return true;
+ }
+ return false;
}
@@ -369,8 +375,8 @@ mark_control_dependent_edges_necessary (basic_block bb, bool ignore_self)
continue;
}
- if (!bitmap_bit_p (last_stmt_necessary, cd_bb->index))
- mark_last_stmt_necessary (cd_bb);
+ if (!mark_last_stmt_necessary (cd_bb))
+ mark_control_dependent_edges_necessary (cd_bb, false);
}
if (!skipped)
@@ -790,8 +796,8 @@ propagate_necessity (bool aggressive)
if (gimple_bb (stmt)
!= get_immediate_dominator (CDI_POST_DOMINATORS, arg_bb))
{
- if (!bitmap_bit_p (last_stmt_necessary, arg_bb->index))
- mark_last_stmt_necessary (arg_bb);
+ if (!mark_last_stmt_necessary (arg_bb))
+ mark_control_dependent_edges_necessary (arg_bb, false);
}
else if (arg_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& !bitmap_bit_p (visited_control_parents,
--
2.35.3
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[not found] <20230210101245.1440C385B514@sourceware.org>
2023-02-13 14:42 ` [PATCH] tree-optimization/106722 - fix CD-DCE edge marking Jeff Law
2023-02-10 21:16 Jan Hubicka
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2023-02-10 10:12 Richard Biener
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