rs6000: New darn testcase (PR91481)

We used to implement darn with unspecs, not unspec_volatiles, which
means two darn instructions could be CSEd together.

This testcase tests it by adding together four random numbers.  If all
is well that means we get four darn instructions, because such a small
loop is unrolled fine at -O2 already.  If things go bad, combine will
combine it all to one darn and a shift left by two.

gcc/testsuite/
	PR target/91481
	* gcc.target/powerpc/darn-3.c: New testcase.

From-SVN: r274889

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8e9071371647255fe61c59cfc393aa9ea777d593..f657cfa1a632843801acbdc94c65e10f00e3662f 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-08-23  Segher Boessenkool  <segher@kernel.crashing.org>
+
+       PR target/91481
+       * gcc.target/powerpc/darn-3.c: New testcase.
+
 2019-08-23  Marek Polacek  <polacek@redhat.com>
 
        PR c++/79817 - attribute deprecated on namespace.

diff --git a/gcc/testsuite/gcc.target/powerpc/darn-3.c b/gcc/testsuite/gcc.target/powerpc/darn-3.c
new file mode 100644 (file)
index 0000000..477901f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/darn-3.c
@@ -0,0 +1,16 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-skip-if "" { powerpc*-*-aix* } } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
+
+static int darn32(void) { return __builtin_darn_32(); }
+
+int four(void)
+{
+       int sum = 0;
+       int i;
+       for (i = 0; i < 4; i++)
+               sum += darn32();
+       return sum;
+}
+
+/* { dg-final { scan-assembler-times {(?n)\mdarn .*,0\M} 4 } } */