[test] Fix tests for changed optimizer warning message

[Meinersbur]

Summary

The warning message "loop not vectorized: failed explicitly specified loop vectorization" changes to "loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering" in D49281. Apply this change in clang's test cases.

[dmgreen]

This looks fine, of course, to go alongside D49281.

[Meinersbur]

Committed together with D49281 in rC348944.

test/Misc/backend-optimization-failure-nodbg.cpp

 // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -O3 -emit-llvm -S -verify -o /dev/null
 // REQUIRES: x86-registered-target
 
 // Test verifies optimization failures generated by the backend are handled
 // correctly by clang. LLVM tests verify all of the failure conditions.
 
-void test_switch(int *A, int *B, int Length, int J) { /* expected-warning {{loop not vectorized: failed explicitly specified loop vectorization}} */
+void test_switch(int *A, int *B, int Length, int J) { /* expected-warning {{loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering}} */
 #pragma clang loop vectorize(enable) unroll(disable)
   for (int i = 0; i < Length; i++) {
     switch (A[i]) {
     case 0:
       B[i] = 1;
       break;
     case 1:
       B[J] = 2;
       break;
     default:
       B[i] = 3;
     }
   }
 }

test/Misc/backend-optimization-failure.cpp

 // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -O3 -emit-llvm -debug-info-kind=line-tables-only -S -verify -o /dev/null
 // REQUIRES: x86-registered-target
 
 // Test verifies optimization failures generated by the backend are handled
 // correctly by clang. LLVM tests verify all of the failure conditions.
 
 void test_switch(int *A, int *B, int Length,int J) {
 #pragma clang loop vectorize(enable) unroll(disable)
   for (int i = 0; i < Length; i++) {
-/* expected-warning@-1 {{loop not vectorized: failed explicitly specified loop vectorization}} */ switch (A[i]) {
+/* expected-warning@-1 {{loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering}} */ switch (A[i]) {
     case 0:
       B[i] = 1;
       break;
     case 1:
       B[J] = 2;
       break;
     default:
       B[i] = 3;
     }
   }
 }