re PR tree-optimization/67328 (range test rather than single bit test for code testing enum values)

2017-06-13  Yury Gribov  <tetra2005@gmail.com>

gcc/
	PR tree-optimization/67328
	* fold-const.c (maskable_range_p): New function.
	(build_range_check): Generate bittests if possible.

gcc/testsuite/
	PR tree-optimization/67328
	* c-c++-common/fold-masked-cmp-1.c: New test.
	* c-c++-common/fold-masked-cmp-2.c: Likewise.
	* gcc.dg/pr46309.c: Fix pattern.
	* gcc.dg/pr46309-2.c: Likewise.

From-SVN: r249149

gcc/ChangeLog

+2017-06-13  Yury Gribov  <tetra2005@gmail.com>
+
+	PR tree-optimization/67328
+	* fold-const.c (maskable_range_p): New function.
+	(build_range_check): Generate bittests if possible.
+
 2017-06-13  Martin Liska  <mliska@suse.cz>
 
 	* gimple-pretty-print.c (dump_probability): Add new argument.

gcc/fold-const.c

@@ -4745,6 +4745,40 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh,
   *pin_p = in_p, *plow = low, *phigh = high;
   return exp;
 }
+
+/* Returns TRUE if [LOW, HIGH] range check can be optimized to
+   a bitwise check i.e. when
+     LOW  == 0xXX...X00...0
+     HIGH == 0xXX...X11...1
+   Return corresponding mask in MASK and stem in VALUE.  */
+
+static bool
+maskable_range_p (const_tree low, const_tree high, tree type, tree *mask,
+		  tree *value)
+{
+  if (TREE_CODE (low) != INTEGER_CST
+      || TREE_CODE (high) != INTEGER_CST)
+    return false;
+
+  unsigned prec = TYPE_PRECISION (type);
+  wide_int lo = wi::to_wide (low, prec);
+  wide_int hi = wi::to_wide (high, prec);
+
+  wide_int end_mask = lo ^ hi;
+  if ((end_mask & (end_mask + 1)) != 0
+      || (lo & end_mask) != 0)
+    return false;
+
+  wide_int stem_mask = ~end_mask;
+  wide_int stem = lo & stem_mask;
+  if (stem != (hi & stem_mask))
+    return false;
+
+  *mask = wide_int_to_tree (type, stem_mask);
+  *value = wide_int_to_tree (type, stem);
+
+  return true;
+}
 
 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
    type, TYPE, return an expression to test if EXP is in (or out of, depending
@@ -4754,7 +4788,7 @@ tree
 build_range_check (location_t loc, tree type, tree exp, int in_p,
 		   tree low, tree high)
 {
-  tree etype = TREE_TYPE (exp), value;
+  tree etype = TREE_TYPE (exp), mask, value;
 
   /* Disable this optimization for function pointer expressions
      on targets that require function pointer canonicalization.  */
@@ -4787,6 +4821,13 @@ build_range_check (location_t loc, tree type, tree exp, int in_p,
     return fold_build2_loc (loc, EQ_EXPR, type, exp,
 			fold_convert_loc (loc, etype, low));
 
+  if (TREE_CODE (exp) == BIT_AND_EXPR
+      && maskable_range_p (low, high, etype, &mask, &value))
+    return fold_build2_loc (loc, EQ_EXPR, type,
+			    fold_build2_loc (loc, BIT_AND_EXPR, etype,
+					      exp, mask),
+			    value);
+
   if (integer_zerop (low))
     {
       if (! TYPE_UNSIGNED (etype))

gcc/testsuite/ChangeLog

+2017-06-13  Yury Gribov  <tetra2005@gmail.com>
+
+	PR tree-optimization/67328
+	* c-c++-common/fold-masked-cmp-1.c: New test.
+	* c-c++-common/fold-masked-cmp-2.c: Likewise.
+	* gcc.dg/pr46309.c: Fix pattern.
+	* gcc.dg/pr46309-2.c: Likewise.
+
 2017-06-13  Tamar Christina  <tamar.christina@arm.com>
 
 	* gcc.target/arm/sdiv_costs_1.c:

gcc/testsuite/c-c++-common/fold-masked-cmp-1.c

+/* Based on PR 67328 */
+
+/* { dg-do compile { target x86_64-*-* } } */
+/* { dg-options "-O2" } */
+
+enum output_type
+{
+  type_pde,
+  type_pie,
+  type_relocatable,
+  type_dll,
+};
+
+struct bfd_link_info
+{
+  enum output_type type : 2;
+  unsigned int pad : 30;
+};
+
+#define bfd_link_pde(info)	   ((info)->type == type_pde)
+#define bfd_link_dll(info)	   ((info)->type == type_dll)
+#define bfd_link_relocatable(info) ((info)->type == type_relocatable)
+#define bfd_link_pie(info)	   ((info)->type == type_pie)
+#define bfd_link_executable(info)  (bfd_link_pde (info) || bfd_link_pie (info))
+#define bfd_link_pic(info)	   (bfd_link_dll (info) || bfd_link_pie (info))
+
+int result;
+
+void test_pic (struct bfd_link_info *info)
+{
+  if (bfd_link_pic (info))
+    result++;
+}
+
+int test_exe (struct bfd_link_info *info)
+{
+  if (bfd_link_executable (info))
+    result++;
+}
+
+/* { dg-final { scan-assembler-times "testn?b" 2 } } */

gcc/testsuite/c-c++-common/fold-masked-cmp-2.c

+/* Based on PR 67328 */
+
+/* { dg-do compile { target x86_64-*-* } } */
+/* { dg-options "-O2" } */
+
+enum output_type
+{
+  type_pde,
+  type_relocatable,
+  type_pie,
+  type_dll,
+};
+
+struct bfd_link_info
+{
+  enum output_type type : 2;
+  unsigned int pad : 30;
+};
+
+#define bfd_link_pde(info)	   ((info)->type == type_pde)
+#define bfd_link_dll(info)	   ((info)->type == type_dll)
+#define bfd_link_relocatable(info) ((info)->type == type_relocatable)
+#define bfd_link_pie(info)	   ((info)->type == type_pie)
+#define bfd_link_executable(info)  (bfd_link_pde (info) || bfd_link_pie (info))
+#define bfd_link_pic(info)	   (bfd_link_dll (info) || bfd_link_pie (info))
+
+int result;
+
+void test_pic (struct bfd_link_info *info)
+{
+  if (bfd_link_pic (info))
+    result++;
+}
+
+int test_exe (struct bfd_link_info *info)
+{
+  if (bfd_link_executable (info))
+    result++;
+}
+
+/* { dg-final { scan-assembler-times "testn?b" 2 } } */
+

gcc/testsuite/gcc.dg/pr46309-2.c

@@ -142,4 +142,4 @@ f10 (int a)
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.0, 31. and -.64, 95.\[\n\r\]* into" 1 "reassoc1" } } */
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.128, 159. and -.192, 223.\[\n\r\]* into" 1 "reassoc1" } } */
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.1, 1. and -.2, 2. and -.3, 3. and -.4, 4. and -.5, 5. and -.6, 6. and -.7, 7. and -.8, 8.\[\n\r\]* into" 7 "reassoc1" } } */
-/* { dg-final { scan-tree-dump-times "Optimizing range tests \[^\r\n\]*_\[0-9\]* -.0, 31. and -.128, 159.\[\n\r\]* into" 1 "reassoc2" } } */
+/* { dg-final { scan-tree-dump-times "Optimizing range tests \[^\r\n\]*_\[0-9\]* -.0, 0. and -.128, 128.\[\n\r\]* into" 1 "reassoc2" } } */

gcc/testsuite/gcc.dg/pr46309.c

@@ -65,4 +65,4 @@ f6 (unsigned int a)
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.1, 1. and -.2, 2.\[\n\r\]* into" 1 "reassoc1" } } */
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.0, 31. and -.64, 95.\[\n\r\]* into" 2 "reassoc1" } } */
 /* { dg-final { scan-tree-dump-times "Optimizing range tests a_\[0-9\]*.D. -.128, 159. and -.192, 223.\[\n\r\]* into" 1 "reassoc1" } } */
-/* { dg-final { scan-tree-dump-times "Optimizing range tests \[^\r\n\]*_\[0-9\]* -.0, 31. and -.128, 159.\[\n\r\]* into" 1 "reassoc2" } } */
+/* { dg-final { scan-tree-dump-times "Optimizing range tests \[^\r\n\]*_\[0-9\]* -.0, 0. and -.128, 128.\[\n\r\]* into" 1 "reassoc2" } } */