[NFC][AIX][clang] un-XFAIL gcc profile flag compat test

[daltenty]

Summary

We can pass this test now thanks to recent changes that allow us to use PGO without LTO, so un-XFAIL the test and update the comments.

[stevewan]

Extra coverage for LTO doesn't hurt. LGTM. Thanks.

[sfertile]

Thanks David.

clang/test/Profile/gcc-flag-compatibility-aix.c

 // Tests for -fprofile-generate and -fprofile-use flag compatibility. These two
 // flags behave similarly to their GCC counterparts:
 //
 // -fprofile-generate         Generates the profile file ./default.profraw
 // -fprofile-generate=<dir>   Generates the profile file <dir>/default.profraw
 // -fprofile-use              Uses the profile file ./default.profdata
 // -fprofile-use=<dir>        Uses the profile file <dir>/default.profdata
 // -fprofile-use=<dir>/file   Uses the profile file <dir>/file
 
-// On AIX, -flto is required with -fprofile-generate
+// On AIX, -flto used to be required with -fprofile-generate, so test those
+// extra cases.
 
 // RUN: %clang %s -c -S -o - -emit-llvm -target powerpc64-unknown-aix -flto -fprofile-generate | FileCheck -check-prefix=PROFILE-GEN %s
 // PROFILE-GEN: @__profc_main = {{(private|internal)}} global [2 x i64] zeroinitializer, section
 // PROFILE-GEN: @__profd_main =
 
 // Check that -fprofile-generate=/path/to generates /path/to/default.profraw
 // RxUN: %clang %s -c -S -o - -emit-llvm -target powerpc64-unknown-aix -flto -fprofile-generate=/path/to | FileCheck -check-prefixes=PROFILE-GEN,PROFILE-GEN-EQ %s
 // PROFILE-GEN-EQ: constant [{{.*}} x i8] c"/path/to{{/|\\\\}}{{.*}}\00"

clang/test/Profile/gcc-flag-compatibility.c

 // Tests for -fprofile-generate and -fprofile-use flag compatibility. These two
 // flags behave similarly to their GCC counterparts:
 //
 // -fprofile-generate         Generates the profile file ./default.profraw
 // -fprofile-generate=<dir>   Generates the profile file <dir>/default.profraw
 // -fprofile-use              Uses the profile file ./default.profdata
 // -fprofile-use=<dir>        Uses the profile file <dir>/default.profdata
 // -fprofile-use=<dir>/file   Uses the profile file <dir>/file
 
-// On AIX, -flto is required with -fprofile-generate. gcc-flag-compatibility-aix.c is used to do the testing on AIX with -flto
-// XFAIL: aix
+// On AIX, -flto used to be required with -fprofile-generate. gcc-flag-compatibility-aix.c is used to do the testing on AIX with -flto
 // RUN: %clang %s -c -S -o - -emit-llvm -fprofile-generate | FileCheck -check-prefix=PROFILE-GEN %s
 // PROFILE-GEN: @__profc_main = {{(private|internal)}} global [2 x i64] zeroinitializer, section
 // PROFILE-GEN: @__profd_main =
 
 // Check that -fprofile-generate=/path/to generates /path/to/default.profraw
 // RxUN: %clang %s -c -S -o - -emit-llvm -fprofile-generate=/path/to | FileCheck -check-prefixes=PROFILE-GEN,PROFILE-GEN-EQ %s
 // PROFILE-GEN-EQ: constant [{{.*}} x i8] c"/path/to{{/|\\\\}}{{.*}}\00"