SamplePGO - Fix PR 25482 - Do not rely on llvm.dbg.cu for discriminators

The discriminators pass relied on the presence of llvm.dbg.cu to decide
whether to add discriminators, but this fails in the case where debug
info is only enabled partially when -fprofile-sample-use is active.

The reason llvm.dbg.cu is not present in these cases is to prevent
codegen from emitting debug info (as it is only used for the sample
profile pass).

This changes the discriminators pass to also emit discriminators even
when debug info is not being emitted.

llvm-svn: 252763

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/test/Transforms/AddDiscriminators/multiple.ll b/llvm/test/Transforms/AddDiscriminators/multiple.ll
index 949ae5c4093..9a05fcd8686 100644
--- a/llvm/test/Transforms/AddDiscriminators/multiple.ll
+++ b/llvm/test/Transforms/AddDiscriminators/multiple.ll
@@ -47,7 +47,11 @@ if.end:                                           ; preds = %if.else, %if.then
 
 attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
-!llvm.dbg.cu = !{!0}
+; We should be able to add discriminators even in the absence of llvm.dbg.cu.
+; When using sample profiles, the front end will generate line tables but it
+; does not generate llvm.dbg.cu to prevent codegen from emitting debug info
+; to the final binary.
+; !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!7, !8}
 !llvm.ident = !{!9}