[AVR] Fix a big in shift operator lowering; Authored by Dr. Gergo Erdi

When generating code for a shift loop, check the shift
 amount against the literal value 0, not R0

llvm-svn: 304284
diff --git a/llvm/test/CodeGen/AVR/rot.ll b/llvm/test/CodeGen/AVR/rot.ll
index e43daf3..a7b77d9 100644
--- a/llvm/test/CodeGen/AVR/rot.ll
+++ b/llvm/test/CodeGen/AVR/rot.ll
@@ -6,7 +6,7 @@
 define i8 @rol8(i8 %val, i8 %amt) {
   ; CHECK:      andi r22, 7
 
-  ; CHECK-NEXT: cp r22, r0
+  ; CHECK-NEXT: cpi r22, 0
   ; CHECK-NEXT: breq LBB0_2
 
 ; CHECK-NEXT: LBB0_1:
@@ -32,7 +32,7 @@
 define i8 @ror8(i8 %val, i8 %amt) {
   ; CHECK:      andi r22, 7
 
-  ; CHECK-NEXT: cp r22, r0
+  ; CHECK-NEXT: cpi r22, 0
   ; CHECK-NEXT: breq LBB1_2
 
 ; CHECK-NEXT: LBB1_1: