gcc.target/cris/pr93372-1.c: New test.

This test was separated from the posted and approved patch named
"dbr: Filter-out TARGET_FLAGS_REGNUM from end_of_function_needs"
and applied: it doesn't fail yet.  It differs from the posted
version in that function "g" is commented-out; see the added
comment.

2 files changed, 74 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1b48abd..b418065 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -2,6 +2,8 @@
 
 	* gcc.target/cris/cris.exp (check_effective_target_cc0): New.
 
+	* gcc.target/cris/pr93372-1.c: New test.
+
 2020-02-10  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/91913
diff --git a/gcc/testsuite/gcc.target/cris/pr93372-1.c b/gcc/testsuite/gcc.target/cris/pr93372-1.c
new file mode 100644
index 0000000..20aa65e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/cris/pr93372-1.c
@@ -0,0 +1,72 @@
+/* Check that all more-or-less trivially fillable delayed-branch-slots
+   are filled. */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler-not "\tnop" } } */
+
+void *f(void **p)
+{
+  /* Supposedly the memory read finds its way into the "ret"
+     delay-slot. */
+  return *p;
+}
+
+#if 0
+/* Until the negative effects of g:897a73086b2 a.k.a. r10-6395
+   a.k.a. "One more fix for PR 91333 - suboptimal register allocation
+   for inline asm", which appears to have caused a "nop" (unfilled
+   delay-slot) to appear for this function for CRIS-decc0rated (but not
+   CRIS-cc0) and increasing one execution-path by one instruction (and
+   the size of the whole function), it's left out.  It was but a mere
+   attempt to expose the flaw better noticed with xlshrdi3.  It exposes
+   a real issue, just less important.  FIXME: extract to separate test.  */
+int g(int *x, int *y, char *v, int n)
+{
+  int z = *x;
+  int w = *v + 31;
+
+  /* Two branch and two return slots, all filled. */
+  if (z != 23 && z != n+1)
+    return *x+*y+24+w;
+  return *y+24+w;
+}
+#endif
+
+/* No problem with the two examples above, but with a more involved
+   example, the epilogue contents matter (the condition-code register
+   clobber was mistaken for a register that needed to be alive). */
+
+struct DWstruct {int low, high;};
+typedef unsigned long long DItype;
+typedef unsigned int USItype;
+
+typedef union
+{
+  struct DWstruct s;
+  DItype ll;
+} DWunion;
+
+unsigned long long
+xlshrdi3 (DItype u, unsigned int b)
+{
+  if (b == 0)
+    return u;
+
+  const DWunion uu = {.ll = u};
+  const int bm = (4 * 8) - b;
+  DWunion w;
+
+  if (bm <= 0)
+    {
+      w.s.high = 0;
+      w.s.low = (USItype) uu.s.high >> -bm;
+    }
+  else
+    {
+      const USItype carries = (USItype) uu.s.high << bm;
+      w.s.high = (USItype) uu.s.high >> b;
+      w.s.low = ((USItype) uu.s.low >> b) | carries;
+    }
+
+  return w.ll;
+}