PR77644

[Prathamesh Kulkarni]

Hi,
The attached patch adds the following pattern to match.pd
sqrt(x) cmp sqrt(y) -> x cmp y.
and is enabled with -funsafe-math-optimization and -fno-math-errno.

Bootstrapped+tested on x86_64-unknown-linux-gnu.
Cross-tested on arm*-*-*, aarch64*-*-*.
OK for trunk ?

Thanks,
Prathamesh

2017-05-09  Prathamesh Kulkarni  <prathamesh.kulka...@linaro.org>

        PR tree-optimization/77644
        * match.pd (sqrt(x) cmp sqrt(y) -> x cmp y): New pattern.

testsuite/
        * gcc.dg/tree-ssa/pr77644.c: New test-case.

diff --git a/gcc/match.pd b/gcc/match.pd
index e3d98baa12f..9929f5a1c16 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2633,7 +2633,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
         (if (GENERIC)
          (truth_andif
           (ge @0 { build_real (TREE_TYPE (@0), dconst0); })
-          (cmp @0 { build_real (TREE_TYPE (@0), c2); }))))))))))))
+          (cmp @0 { build_real (TREE_TYPE (@0), c2); })))))))))
+
+   /* PR77644: Transform sqrt(x) cmp sqrt(y) -> x cmp y.  */
+   (simplify
+    (cmp (sq @0) (sq @1))
+      (if (! HONOR_NANS (type))
+       (cmp @0 @1))))))
 
 /* Fold A /[ex] B CMP C to A CMP B * C.  */
 (for cmp (eq ne)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr77644.c 
b/gcc/testsuite/gcc.dg/tree-ssa/pr77644.c
new file mode 100644
index 00000000000..30da66374e6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr77644.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target c99_runtime } */
+/* { dg-options "-O2 -fdump-tree-optimized -funsafe-math-optimizations 
-fno-math-errno" } */
+
+#define FOO(type, cmp, suffix, no)  \
+int f_##no(type x, type y) \
+{ \
+  type gen_##no(); \
+  type xs = __builtin_sqrt##suffix((gen_##no())); \
+  type xy = __builtin_sqrt##suffix((gen_##no())); \
+  return (xs cmp xy); \
+}
+
+#define GEN_FOO(type, suffix) \
+FOO(type, <, suffix, suffix##1) \
+FOO(type, <=, suffix, suffix##2) \
+FOO(type, >, suffix, suffix##3) \
+FOO(type, >=, suffix, suffix##4) \
+FOO(type, ==, suffix, suffix##5) \
+FOO(type, !=, suffix, suffix##6)
+
+GEN_FOO(float, f)
+GEN_FOO(double, )
+GEN_FOO(long double, l)
+
+/* { dg-final { scan-tree-dump-not "__builtin_sqrtf" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "__builtin_sqrt" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "__builtin_sqrtl" "optimized" } } */