[SMS] Fix violation of memory dependence

Submitted by Revital Eres on June 15, 2011, 8:45 a.m.

Details

Message ID BANLkTikALCMovevvKKXj2VDPw_z1U4hjEA@mail.gmail.com
State New
Headers show

Commit Message

Revital Eres June 15, 2011, 8:45 a.m.
Hello,

>>>         * ddg.c (add_intra_loop_mem_dep): New function.
>
> You could check first thing if (from->cuid == to->cuid), for code clarity.

Attached is the new version of the patch which addresses this.

The patch was re-tested as follows:
On ppc64-redhat-linux regtest as well as bootstrap with SMS flags
enabling SMS also on loops with stage count 1.  Regtested on SPU.
On arm-linux-gnueabi bootstrap c language with SMS
flags enabling SMS also on loops with stage count 1
and currently regression testing on c,c++.

OK for mainline once regtest on arm-linux-gnueabi completes?

Thanks,
Revital

gcc/
        * ddg.c (add_intra_loop_mem_dep): New function.
        (build_intra_loop_deps): Call it.

testsuite/
        * gcc.dg/sms-9.c: New file.

Patch hide | download patch | download mbox

Index: ddg.c
===================================================================
--- ddg.c	(revision 174906)
+++ ddg.c	(working copy)
@@ -390,6 +390,38 @@  insns_may_alias_p (rtx insn1, rtx insn2)
 			 &PATTERN (insn2));
 }
 
+/* Given two nodes, analyze their RTL insns and add intra-loop mem deps
+   to ddg G.  */
+static void
+add_intra_loop_mem_dep (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to)
+{
+
+  if ((from->cuid == to->cuid)
+      || !insns_may_alias_p (from->insn, to->insn))
+    /* Do not create edge if memory references have disjoint alias sets
+       or 'to' and 'from' are the same instruction.  */
+    return;
+
+  if (mem_write_insn_p (from->insn))
+    {
+      if (mem_read_insn_p (to->insn))
+	create_ddg_dep_no_link (g, from, to,
+				DEBUG_INSN_P (to->insn)
+				? ANTI_DEP : TRUE_DEP, MEM_DEP, 0);
+      else
+	create_ddg_dep_no_link (g, from, to,
+				DEBUG_INSN_P (to->insn)
+				? ANTI_DEP : OUTPUT_DEP, MEM_DEP, 0);
+    }
+  else
+    {
+      if (mem_read_insn_p (to->insn))
+	return;
+      else
+	create_ddg_dep_no_link (g, from, to, ANTI_DEP, MEM_DEP, 0);
+    }
+}
+
 /* Given two nodes, analyze their RTL insns and add inter-loop mem deps
    to ddg G.  */
 static void
@@ -477,10 +509,22 @@  build_intra_loop_deps (ddg_ptr g)
 	      if (DEBUG_INSN_P (j_node->insn))
 		continue;
 	      if (mem_access_insn_p (j_node->insn))
- 		/* Don't bother calculating inter-loop dep if an intra-loop dep
-		   already exists.  */
+		{
+		  /* Don't bother calculating inter-loop dep if an intra-loop dep
+		     already exists.  */
 	      	  if (! TEST_BIT (dest_node->successors, j))
 		    add_inter_loop_mem_dep (g, dest_node, j_node);
+		  /* If -fmodulo-sched-allow-regmoves
+		     is set certain anti-dep edges are not created.
+		     It might be that these anti-dep edges are on the
+		     path from one memory instruction to another such that
+		     removing these edges could cause a violation of the
+		     memory dependencies.  Thus we add intra edges between
+		     every two memory instructions in this case.  */
+		  if (flag_modulo_sched_allow_regmoves
+		      && !TEST_BIT (dest_node->predecessors, j))
+		    add_intra_loop_mem_dep (g, j_node, dest_node);
+		}
             }
         }
     }
Index: testsuite/gcc.dg/sms-9.c
===================================================================
--- testsuite/gcc.dg/sms-9.c	(revision 0)
+++ testsuite/gcc.dg/sms-9.c	(revision 0)
@@ -0,0 +1,60 @@ 
+/* { dg-do run } */
+/* { dg-options "-O2 -fmodulo-sched -fno-auto-inc-dec -O2 -fmodulo-sched-allow-regmoves" } */
+
+#include <stdlib.h>
+#include <stdarg.h>
+
+struct df_ref_info
+{
+  unsigned int *begin;
+  unsigned int *count;
+};
+
+extern void *memset (void *s, int c, __SIZE_TYPE__ n);
+
+
+__attribute__ ((noinline))
+int
+df_reorganize_refs_by_reg_by_insn (struct df_ref_info *ref_info,
+			           int num, unsigned int start)
+{
+  unsigned int m = num;
+  unsigned int offset = 77;
+  unsigned int r;
+
+  for (r = start; r < m; r++)
+    {
+      ref_info->begin[r] = offset;
+      offset += ref_info->count[r];
+      ref_info->count[r] = 0;
+    }
+
+  return offset;
+}
+
+int
+main ()
+{
+  struct df_ref_info temp;
+  int num = 100;
+  unsigned int start = 5;
+  int i, offset;
+
+  temp.begin = malloc (100 * sizeof (unsigned int));
+  temp.count = malloc (100 * sizeof (unsigned int));
+
+  memset (temp.begin, 0, sizeof (unsigned int) * num);
+  memset (temp.count, 0, sizeof (unsigned int) * num);
+
+  for (i = 0; i < num; i++)
+    temp.count[i] = i + 1;
+
+  offset = df_reorganize_refs_by_reg_by_insn (&temp, num, start);
+
+  if (offset != 5112)
+    abort ();
+
+  free (temp.begin);
+  free (temp.count);
+  return 0;
+}