Fix vectorization remarks.

This patch changes the vectorization remarks to also inform when
vectorization is possible but not beneficial.

Added tests to exercise some loop remarks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207574 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/LoopUnroll/loop-remarks.ll

@@ -0,0 +1,25 @@
+; RUN: opt < %s -S -loop-unroll -pass-remarks=loop-unroll -unroll-count=16 2>&1 | FileCheck -check-prefix=COMPLETE-UNROLL %s
+; RUN: opt < %s -S -loop-unroll -pass-remarks=loop-unroll -unroll-count=4 2>&1 | FileCheck -check-prefix=PARTIAL-UNROLL %s
+
+; COMPLETE-UNROLL: remark: {{.*}}: completely unrolled loop with 16 iterations
+; PARTIAL-UNROLL: remark: {{.*}}: unrolled loop by a factor of 4
+
+define i32 @sum() {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %s.06 = phi i32 [ 0, %entry ], [ %add1, %for.body ]
+  %i.05 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %add = add nsw i32 %i.05, 4
+  %call = tail call i32 @baz(i32 %add) #2
+  %add1 = add nsw i32 %call, %s.06
+  %inc = add nsw i32 %i.05, 1
+  %exitcond = icmp eq i32 %inc, 16
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret i32 %add1
+}
+
+declare i32 @baz(i32)