[LoopIdom] Add pre-commit crash for crc with DL

Author: artagnon

llvm/test/Transforms/LoopIdiom/cyclic-redundancy-check-dl.ll

@@ -0,0 +1,25 @@
+; REQUIRES: asserts
+; RUN: not --crash opt -passes=loop-idiom -S %s
+
+target datalayout = "p:16:16"
+
+define void @test_with_dl() {
+entry:
+  br label %ph
+
+ph:
+  %crc.use = phi i32 [ 0, %entry ], [ %crc.next, %loop ]
+  br label %loop
+
+loop:
+  %iv = phi i16 [ 0, %ph ], [ %iv.next, %loop ]
+  %crc = phi i32 [ 0, %ph ], [ %crc.next, %loop ]
+  %lshr.crc.1 = lshr i32 %crc, 1
+  %crc.and.1 = and i32 %crc, 1
+  %sb.check = icmp eq i32 %crc.and.1, 0
+  %xor = xor i32 %lshr.crc.1, 0
+  %crc.next = select i1 %sb.check, i32 %lshr.crc.1, i32 %xor
+  %iv.next = add i16 %iv, 1
+  %exit.cond = icmp ult i16 %iv, 7
+  br i1 %exit.cond, label %loop, label %ph
+}