make sure we always handle small negatives well

llvm-svn: 22503

llvm/test/Regression/CodeGen/Alpha/i32_sub_1.ll

@@ -0,0 +1,10 @@
+; Make sure this testcase codegens to the ctpop instruction
+; RUN: llvm-as < %s | llc -march=alpha | grep -i 'subl $16,1,$0'
+
+implementation   ; Functions:
+
+int %foo(int %x) {
+entry:
+	%tmp.1 = add int %x, -1		; <int> [#uses=1]
+	ret int %tmp.1
+}