optimize tanh(x) / sinh (x) to 1/ cosh (x)

gcc/
	* match.pd (tanh/sinh -> 1/cosh): New simplification.

gcc/testsuite

	* gcc.dg/tanhbysinh.c: New testcase.

diff --git a/gcc/match.pd b/gcc/match.pd
index 33ee1a920bf4a036cc5fdb3c96b38b52765bdefb..2b8c37e690e88b88408a4655262ef1a38e2ee53f 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5229,6 +5229,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (rdiv (SINH:s @0) (COSH:s @0))
    (TANH @0))
 
+ /* Simplify tanh (x) / sinh (x) -> 1.0 / cosh (x). */
+ (simplify
+   (rdiv (TANH:s @0) (SINH:s @0))
+   (rdiv {build_one_cst (type);} (COSH @0)))
+
  /* Simplify cos(x) / sin(x) -> 1 / tan(x). */
  (simplify
   (rdiv (COS:s @0) (SIN:s @0))

diff --git a/gcc/testsuite/gcc.dg/tanhbysinh.c b/gcc/testsuite/gcc.dg/tanhbysinh.c
new file mode 100644 (file)
index 0000000..fde72c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tanhbysinh.c
@@ -0,0 +1,40 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+extern float sinhf (float);
+extern float tanhf (float);
+extern double sinh (double);
+extern double tanh (double);
+extern long double sinhl (long double);
+extern long double tanhl (long double);
+
+double __attribute__ ((noinline))
+tanhbysinh_ (double x)
+{
+    return tanh (x) / sinh (x);
+}
+
+float __attribute__ ((noinline))
+tanhbysinhf_ (float x)
+{
+    return tanhf (x) / sinhf (x);
+}
+
+long double __attribute__ ((noinline))
+tanhbysinhl_ (long double x)
+{
+    return tanhl (x) / sinhl (x);
+}
+
+
+/* There must be no calls to sinh or atanh */
+/* There must be calls to cosh */
+/* {dg-final { scan-tree-dump-not "sinh " "optimized" } } */
+/* {dg-final { scan-tree-dump-not "tanh " "optimized" }} */
+/* {dg-final { scan-tree-dump-not "sinhf " "optimized" } } */
+/* {dg-final { scan-tree-dump-not "tanhf " "optimized" }} */
+/* {dg-final { scan-tree-dump-not "sinhl " "optimized" } } */
+/* {dg-final { scan-tree-dump-not "tanhl " "optimized" }} */
+/* { dg-final { scan-tree-dump "cosh " "optimized" } } */
+/* { dg-final { scan-tree-dump "coshf " "optimized" } } */
+/* { dg-final { scan-tree-dump "coshl " "optimized" } } */
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