re PR tree-optimization/61743 (Complete unroll is not happened for loops with short upper bound)

2015-01-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/61743
	* tree-ssa-pre.c (insert_into_preds_of_block): Preserve range
	information on PHIs for some simple cases.

	* gcc.dg/tree-ssa/pr61743-1.c: New testcase.
	* gcc.dg/tree-ssa/pr61743-2.c: Likewise.

From-SVN: r219662

gcc/ChangeLog

+2015-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/61743
+	* tree-ssa-pre.c (insert_into_preds_of_block): Preserve range
+	information on PHIs for some simple cases.
+
 2015-01-15  Philipp Tomsich  <philipp.tomsich@theobroma-systems.com>
 
 	* config/arm/arm.md (generic_sched): Specify xgene1 in 'no' list.

gcc/testsuite/ChangeLog

+2015-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/61743
+	* gcc.dg/tree-ssa/pr61743-1.c: New testcase.
+	* gcc.dg/tree-ssa/pr61743-2.c: Likewise.
+
 2015-01-15 Renlin Li <renlin.li@arm.com>
 
 	* gcc.target/aarch64/volatileloadpair-1.c: Correct dg-options.

gcc/testsuite/gcc.dg/tree-ssa/pr61743-1.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -funroll-loops -fdump-tree-cunroll-details" } */
+
+#define N 8
+#define M 14
+typedef unsigned char e_u8;
+e_u8 x[256];
+#define MAX(a,b) ((a)>=(b)?(a):(b))
+#define btype int
+
+static inline void bar1(e_u8 a[4][N], e_u8 b[4][N], btype n)
+{
+  int i, j;
+
+  for(i = 0; i < 4; i++)
+    for(j = 0; j < n; j++)
+      a[i][j] ^= b[i][j];
+}
+
+static inline void bar2(e_u8 a[4][N], e_u8 b[256], btype n)
+{
+  int i, j;
+
+  for(i = 0; i < 4; i++)
+    for(j = 0; j < n; j++)
+      a[i][j] = b[a[i][j]] ;
+}
+
+int foo1 (e_u8 a[4][N], int b1, int b2, e_u8 b[M+1][4][N])
+{
+  btype n;
+  int r, m;
+
+  switch (b2) {
+    case 128: n = 4; break;
+    case 192: n = 6; break;
+    case 256: n = 8; break;
+    default : return (-2);
+  }
+  switch (MAX(b1,b2)) {
+    case 128: m = 10; break;
+    case 192: m = 12; break;
+    case 256: m = 14; break;
+    default : return (-3);
+  }
+  bar1(a,b[m],n);
+  bar2(a,x,n);
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "loop with 4 iterations completely unrolled" 2 "cunroll" } } */
+/* { dg-final { scan-tree-dump-times "loop with 8 iterations completely unrolled" 2 "cunroll" } } */
+/* { dg-final { cleanup-tree-dump "cunroll" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr61743-2.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -funroll-loops -fdump-tree-cunroll-details" } */
+
+#define N 8
+#define M 14
+typedef unsigned char e_u8;
+e_u8 x[256];
+#define MAX(a,b) ((a)>=(b)?(a):(b))
+#define btype e_u8
+
+static inline void bar1(e_u8 a[4][N], e_u8 b[4][N], btype n)
+{
+  int i, j;
+
+  for(i = 0; i < 4; i++)
+    for(j = 0; j < n; j++)
+      a[i][j] ^= b[i][j];
+}
+
+static inline void bar2(e_u8 a[4][N], e_u8 b[256], btype n)
+{
+  int i, j;
+
+  for(i = 0; i < 4; i++)
+    for(j = 0; j < n; j++)
+      a[i][j] = b[a[i][j]] ;
+}
+
+int foo1 (e_u8 a[4][N], int b1, int b2, e_u8 b[M+1][4][N])
+{
+  btype n;
+  int r, m;
+
+  switch (b2) {
+    case 128: n = 4; break;
+    case 192: n = 6; break;
+    case 256: n = 8; break;
+    default : return (-2);
+  }
+  switch (MAX(b1,b2)) {
+    case 128: m = 10; break;
+    case 192: m = 12; break;
+    case 256: m = 14; break;
+    default : return (-3);
+  }
+  bar1(a,b[m],n);
+  bar2(a,x,n);
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "loop with 4 iterations completely unrolled" 2 "cunroll" } } */
+/* { dg-final { scan-tree-dump-times "loop with 8 iterations completely unrolled" 2 "cunroll" } } */
+/* { dg-final { cleanup-tree-dump "cunroll" } } */

gcc/tree-ssa-pre.c

@@ -3184,6 +3184,33 @@ insert_into_preds_of_block (basic_block block, unsigned int exprnum,
   bitmap_insert_into_set (NEW_SETS (block),
 			  newphi);
 
+  /* If we insert a PHI node for a conversion of another PHI node
+     in the same basic-block try to preserve range information.
+     This is important so that followup loop passes receive optimal
+     number of iteration analysis results.  See PR61743.  */
+  if (expr->kind == NARY
+      && CONVERT_EXPR_CODE_P (expr->u.nary->opcode)
+      && TREE_CODE (expr->u.nary->op[0]) == SSA_NAME
+      && gimple_bb (SSA_NAME_DEF_STMT (expr->u.nary->op[0])) == block
+      && INTEGRAL_TYPE_P (type)
+      && INTEGRAL_TYPE_P (TREE_TYPE (expr->u.nary->op[0]))
+      && (TYPE_PRECISION (type)
+	  >= TYPE_PRECISION (TREE_TYPE (expr->u.nary->op[0])))
+      && SSA_NAME_RANGE_INFO (expr->u.nary->op[0]))
+    {
+      wide_int min, max;
+      if (get_range_info (expr->u.nary->op[0], &min, &max) == VR_RANGE
+	  && !wi::neg_p (min, SIGNED)
+	  && !wi::neg_p (max, SIGNED))
+	/* Just handle extension and sign-changes of all-positive ranges.  */
+	set_range_info (temp,
+			SSA_NAME_RANGE_TYPE (expr->u.nary->op[0]),
+			wide_int_storage::from (min, TYPE_PRECISION (type),
+						TYPE_SIGN (type)),
+			wide_int_storage::from (max, TYPE_PRECISION (type),
+						TYPE_SIGN (type)));
+    }
+
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
       fprintf (dump_file, "Created phi ");