diff mbox series

sh: Don't call make_insn_raw in sh_recog_treg_set_expr [PR116189]

Message ID 20240805211553.3743105-1-quic_apinski@quicinc.com
State Committed
Commit 0355c943b9e954e8f59068971d934f1b91ecb729
Headers
Series sh: Don't call make_insn_raw in sh_recog_treg_set_expr [PR116189] |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_gcc_build--master-aarch64 success Build passed
linaro-tcwg-bot/tcwg_gcc_check--master-aarch64 success Test passed
linaro-tcwg-bot/tcwg_gcc_build--master-arm success Build passed
linaro-tcwg-bot/tcwg_gcc_check--master-arm warning Patch is already merged

Commit Message

Andrew Pinski Aug. 5, 2024, 9:15 p.m. UTC 
  This was an interesting compare debug failure to debug. The first symptom
was in gcse which would produce different order of creating psedu-registers. This
was caused by a different order of a hashtable walk, due to the hash table having different
number of entries. Which in turn was due to the number of max insn being different between
the 2 runs. The place max insn uid comes from was in sh_recog_treg_set_expr which is called
via rtx_costs and fwprop would cause rtx_costs in some cases for debug insn related stuff.

Build and tested for sh4-linux-gnu.

	PR target/116189

gcc/ChangeLog:

	* config/sh/sh.cc (sh_recog_treg_set_expr): Don't call make_insn_raw,
	make the insn with a fake uid.

gcc/testsuite/ChangeLog:

	* c-c++-common/torture/pr116189-1.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
---
 gcc/config/sh/sh.cc                           | 12 +++++++-
 .../c-c++-common/torture/pr116189-1.c         | 30 +++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/c-c++-common/torture/pr116189-1.c

Comments

Oleg Endo Aug. 6, 2024, 12:36 a.m. UTC | #1 
On Mon, 2024-08-05 at 14:15 -0700, Andrew Pinski wrote:
> This was an interesting compare debug failure to debug. The first symptom
> was in gcse which would produce different order of creating psedu-registers. This
> was caused by a different order of a hashtable walk, due to the hash table having different
> number of entries. Which in turn was due to the number of max insn being different between
> the 2 runs. The place max insn uid comes from was in sh_recog_treg_set_expr which is called
> via rtx_costs and fwprop would cause rtx_costs in some cases for debug insn related stuff.
> 
> Build and tested for sh4-linux-gnu.


Thanks so much!
I think it should be safe to install this on all open branches.


Best regards,
Oleg Endo


> 
> 	PR target/116189
> 
> gcc/ChangeLog:
> 
> 	* config/sh/sh.cc (sh_recog_treg_set_expr): Don't call make_insn_raw,
> 	make the insn with a fake uid.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* c-c++-common/torture/pr116189-1.c: New test.
> 
> Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
> ---
>  gcc/config/sh/sh.cc                           | 12 +++++++-
>  .../c-c++-common/torture/pr116189-1.c         | 30 +++++++++++++++++++
>  2 files changed, 41 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/c-c++-common/torture/pr116189-1.c
> 
> diff --git a/gcc/config/sh/sh.cc b/gcc/config/sh/sh.cc
> index bc017420381..7391b8df583 100644
> --- a/gcc/config/sh/sh.cc
> +++ b/gcc/config/sh/sh.cc
> @@ -12297,7 +12297,17 @@ sh_recog_treg_set_expr (rtx op, machine_mode mode)
>       have to capture its current state and restore it afterwards.  */
>    recog_data_d prev_recog_data = recog_data;
>  
> -  rtx_insn* i = make_insn_raw (gen_rtx_SET (get_t_reg_rtx (), op));
> +  /* Note we can't use insn_raw here since that increases the uid
> +     and could cause debug compare differences; this insn never leaves
> +     this function so create a dummy one. */
> +  rtx_insn* i = as_a <rtx_insn *> (rtx_alloc (INSN));
> +
> +  INSN_UID (i) = 1;
> +  PATTERN (i) = gen_rtx_SET (get_t_reg_rtx (), op);
> +  INSN_CODE (i) = -1;
> +  REG_NOTES (i) = NULL;
> +  INSN_LOCATION (i) = curr_insn_location ();
> +  BLOCK_FOR_INSN (i) = NULL;
>    SET_PREV_INSN (i) = NULL;
>    SET_NEXT_INSN (i) = NULL;
>  
> diff --git a/gcc/testsuite/c-c++-common/torture/pr116189-1.c b/gcc/testsuite/c-c++-common/torture/pr116189-1.c
> new file mode 100644
> index 00000000000..055c563f43e
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/torture/pr116189-1.c
> @@ -0,0 +1,30 @@
> +/* { dg-additional-options "-fcompare-debug" } */
> +
> +/* PR target/116189 */
> +
> +/* In the sh backend, we used to create insn in the path of rtx_costs.
> +   This means sometimes the max uid for insns would be different between
> +   debugging and non debugging which then would cause gcse's hashtable
> +   to have different number of slots which would cause a different walk
> +   for that hash table.  */
> +
> +extern void ff(void);
> +extern short nn[8][4];
> +typedef unsigned short move_table[4];
> +extern signed long long ira_overall_cost;
> +extern signed long long ira_load_cost;
> +extern move_table *x_ira_register_move_cost[1];
> +struct move { struct move *next; };
> +unsigned short t;
> +void emit_move_list(struct move * list, int freq, unsigned char mode, int regno) {
> +  int cost;
> +  for (; list != 0; list = list->next)
> +  {
> +    ff();
> +    unsigned short aclass = t;
> +    cost = (nn)[mode][aclass] ;
> +    ira_load_cost = cost;
> +    cost = x_ira_register_move_cost[mode][aclass][aclass] * freq ;
> +    ira_overall_cost = cost;
> +  }
> +}
> -- 
> 2.43.0
>
diff mbox series

Patch

diff --git a/gcc/config/sh/sh.cc b/gcc/config/sh/sh.cc
index bc017420381..7391b8df583 100644
--- a/gcc/config/sh/sh.cc
+++ b/gcc/config/sh/sh.cc
@@ -12297,7 +12297,17 @@  sh_recog_treg_set_expr (rtx op, machine_mode mode)
      have to capture its current state and restore it afterwards.  */
   recog_data_d prev_recog_data = recog_data;
 
-  rtx_insn* i = make_insn_raw (gen_rtx_SET (get_t_reg_rtx (), op));
+  /* Note we can't use insn_raw here since that increases the uid
+     and could cause debug compare differences; this insn never leaves
+     this function so create a dummy one. */
+  rtx_insn* i = as_a <rtx_insn *> (rtx_alloc (INSN));
+
+  INSN_UID (i) = 1;
+  PATTERN (i) = gen_rtx_SET (get_t_reg_rtx (), op);
+  INSN_CODE (i) = -1;
+  REG_NOTES (i) = NULL;
+  INSN_LOCATION (i) = curr_insn_location ();
+  BLOCK_FOR_INSN (i) = NULL;
   SET_PREV_INSN (i) = NULL;
   SET_NEXT_INSN (i) = NULL;
 
diff --git a/gcc/testsuite/c-c++-common/torture/pr116189-1.c b/gcc/testsuite/c-c++-common/torture/pr116189-1.c
new file mode 100644
index 00000000000..055c563f43e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/torture/pr116189-1.c
@@ -0,0 +1,30 @@ 
+/* { dg-additional-options "-fcompare-debug" } */
+
+/* PR target/116189 */
+
+/* In the sh backend, we used to create insn in the path of rtx_costs.
+   This means sometimes the max uid for insns would be different between
+   debugging and non debugging which then would cause gcse's hashtable
+   to have different number of slots which would cause a different walk
+   for that hash table.  */
+
+extern void ff(void);
+extern short nn[8][4];
+typedef unsigned short move_table[4];
+extern signed long long ira_overall_cost;
+extern signed long long ira_load_cost;
+extern move_table *x_ira_register_move_cost[1];
+struct move { struct move *next; };
+unsigned short t;
+void emit_move_list(struct move * list, int freq, unsigned char mode, int regno) {
+  int cost;
+  for (; list != 0; list = list->next)
+  {
+    ff();
+    unsigned short aclass = t;
+    cost = (nn)[mode][aclass] ;
+    ira_load_cost = cost;
+    cost = x_ira_register_move_cost[mode][aclass][aclass] * freq ;
+    ira_overall_cost = cost;
+  }
+}