gccrs: add checks for division by zero and left shift overflow

These are ported from the c-family code c-warn.cc and c/c-typchk.cc

Fixes Rust-GCC#2394

gcc/rust/ChangeLog:

	* backend/rust-constexpr.cc (eval_store_expression): check for null
	(eval_call_expression): remove bad warning
	* rust-gcc.cc (arithmetic_or_logical_expression): add warnings

gcc/testsuite/ChangeLog:

	* rust/compile/issue-2394.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/compile/issue-2394.rs b/gcc/testsuite/rust/compile/issue-2394.rs
new file mode 100644
index 0000000..92f7afc
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-2394.rs
@@ -0,0 +1,14 @@
+const A: i32 = (1 / 0);
+// { dg-error "division by zero" "" { target *-*-* } .-1 }
+
+fn main() {
+    let a = 1 / 0;
+    // { dg-error "division by zero" "" { target *-*-* } .-1 }
+
+    let b = 3;
+    let c = b / 0;
+    // { dg-error "division by zero" "" { target *-*-* } .-1 }
+
+    let a = 1 << 500;
+    // { dg-error "left shift count >= width of type" "" { target *-*-* } .-1 }
+}