[test] Avoid loop-unroll.c test getting confused by fadd in git revision

[russell.gallop]

Summary

Saw this test failing as it was matching fadd in a (local) git revision:

F:\git\llvm-project\clang\test\CodeGen\loop-unroll.c:38:30: error: CHECK-DISABLE-UNROLL-NOT: excluded string found in input
// CHECK-DISABLE-UNROLL-NOT: fadd
                             ^
<stdin>:69:92: note: found here
!1 = !{!"clang version 11.0.0 (https://github.com/llvm/llvm-project.git a3eebdb6c1376e528a6fadd5eb33bb6eb986a126)"}

[asbirlea]

Oh, wow! Might I ask you add the same for fmul? We may get a revision like that next time :).
Thank you!

[fhahn]

I think we could also just add a single match for something after the generated functions, to limit the scope of CHECK-NOT, e.g add something like CHECK : !0 =

[asbirlea]

SGTM.

[russell.gallop]

Update to check for start of metadata.

[russell.gallop]

In D73162#1834379, @asbirlea wrote:

Oh, wow! Might I ask you add the same for fmul? We may get a revision like that next time :).
Thank you!

fmul shouldn't have the same problem as git hashes are only hex characters.

In D73162#1834392, @fhahn wrote:

I think we could also just add a single match for something after the generated functions, to limit the scope of CHECK-NOT, e.g add something like CHECK : !0 =

Thanks, that's cleaner.

Note that the diff here is a little confused. There are now no changes to the previous check lines.

clang/test/CodeGen/loop-unroll.c

 // CHECK-DISABLE-UNROLL: fadd
 // CHECK-DISABLE-UNROLL: store
 // CHECK-DISABLE-UNROLL: fmul
 // CHECK-DISABLE-UNROLL: fadd
 // CHECK-DISABLE-UNROLL: store
 // CHECK-DISABLE-UNROLL-NOT: fmul
 // CHECK-DISABLE-UNROLL-NOT: fadd
 // CHECK-DISABLE-UNROLL-NOT: store
+// Limit scope of checking so this does not match "fadd" within git version string
+// CHECK-DISABLE-UNROLL: !0 =
 
 int printf(const char * restrict format, ...);
 
 void for_test() {
   double A[1000], B[1000];
   int L = 500;
   for (int i = 0; i < L; i++) {
     A[i] = i;