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

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>
(cherry picked from commit 0355c943b9e954e8f59068971d934f1b91ecb729)

diff --git a/gcc/config/sh/sh.cc b/gcc/config/sh/sh.cc
index 494e4536251d83135f7b9fce11e47954ad894f92..5455c3fddaaf2913cf85e0eae5413f737e890aac 100644 (file)
--- a/gcc/config/sh/sh.cc
+++ b/gcc/config/sh/sh.cc
@@ -12278,7 +12278,17 @@ 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 (file)
index 0000000..055c563
--- /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;
+  }
+}