match.pd ((X / Y) == 0 -> X < Y): New pattern.

2017-09-26  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	* match.pd ((X / Y) == 0 -> X < Y): New pattern.
	((X / Y) != 0 -> X >= Y): Likewise.

testsuite/
	* gcc.dg/tree-ssa/cmpdiv.c: New test.

From-SVN: r253218

gcc/ChangeLog

+2017-09-26  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	* match.pd ((X / Y) == 0 -> X < Y): New pattern.
+	((X / Y) != 0 -> X >= Y): Likewise.
+
 2017-09-26  Carl Love  <cel@us.ibm.com>
 
 	* config/rs6000/rs6000-c.c (P9V_BUILTIN_VEC_XL_LEN_R,

gcc/match.pd

@@ -1275,6 +1275,18 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	   || TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0))))
    (op @1 @0))))
 
+/* Transform:
+ * (X / Y) == 0 -> X < Y if X, Y are unsigned.
+ * (X / Y) != 0 -> X >= Y, if X, Y are unsigned.
+ */
+(for cmp (eq ne)
+     ocmp (lt ge)
+ (simplify
+  (cmp (trunc_div @0 @1) integer_zerop)
+  (if (TYPE_UNSIGNED (TREE_TYPE (@0))
+       && (VECTOR_TYPE_P (type) || !VECTOR_TYPE_P (TREE_TYPE (@0))))
+   (ocmp @0 @1))))
+
 /* X == C - X can never be true if C is odd.  */
 (for cmp (eq ne)
  (simplify

gcc/testsuite/ChangeLog

+2017-09-26  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+
+	* gcc.dg/tree-ssa/cmpdiv.c: New test.
+
 2017-09-26  Carl Love  <cel@us.ibm.com>
 
 	* gcc.target/powerpc/builtins-5-p9-runnable.c: Add new runable test

gcc/testsuite/gcc.dg/tree-ssa/cmpdiv.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+
+_Bool f1(unsigned x, unsigned y)
+{
+  unsigned t1 = x / y;
+  _Bool t2 = (t1 != 0);
+  return t2;
+}
+
+_Bool f2(unsigned x, unsigned y)
+{
+  unsigned t1 = x / y;
+  _Bool t2 = (t1 == 0);
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump-not "trunc_div_expr" "optimized" } } */