Re: [PATCH 1/2] simplify-rtx: The truncation of an IOR can have all bits set (PR81423)

[Segher Boessenkool]

On Wed, Jul 19, 2017 at 12:19:32AM -0600, Jeff Law wrote:
> On 07/18/2017 01:36 PM, Segher Boessenkool wrote:
> >     * simplify-rtx.c (simplify_truncation): Handle truncating an IOR
> >     with a constant that is -1 in the truncated to mode.
> OK.  A testcase would be advisable :-)
> 
> jeff

Like this.  Is this okay for trunk?  (Is int32plus the correct test
to use here?)


Segher


2017-07-24  Segher Boessenkool  <seg...@kernel.crashing.org>

gcc/testsuite/
        PR rtl-optimization/81423
        * gcc.c-torture/execute/pr81423.c: New testcase.

---
 gcc/testsuite/gcc.c-torture/execute/pr81423.c | 30 +++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr81423.c

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr81423.c 
b/gcc/testsuite/gcc.c-torture/execute/pr81423.c
new file mode 100644
index 0000000..75c3518
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr81423.c
@@ -0,0 +1,30 @@
+/* { dg-require-effective-target int32plus } */
+
+extern void abort (void);
+
+unsigned long long int ll = 0;
+unsigned long long int ull1 = 1ULL;
+unsigned long long int ull2 = 12008284144813806346ULL;
+unsigned long long int ull3;
+
+void
+foo (void)
+{
+  ll = -5597998501375493990LL;
+
+  ll = (5677365550390624949L - ll) - (ull1 > 0);
+  ull3 = (unsigned int)
+    (2067854353L <<
+     (((ll + -2129105131L) ^ 10280750144413668236ULL) -
+      10280750143997242009ULL)) >> ((2873442921854271231ULL | ull2)
+                                   - 12098357307243495419ULL);
+}
+
+int
+main (void)
+{
+  foo ();
+  if (ull3 != 3998784)
+    abort ();
+  return 0;
+}