The absence of noreturn doesn't ensure mayReturn

There are two separate issues:
- LLVM doesn't consider infinite loops to be side effects: we happily
  hoist/sink above/below loops whose bounds are unknown.
- The absence of the noreturn attribute is insufficient for us to know
  if a function will definitely return.  Relying on noreturn in the
  middle-end for any property is an accident waiting to happen.

llvm-svn: 273762

1 files changed, 0 insertions, 18 deletions

diff --git a/llvm/test/Transforms/FunctionAttrs/noreturn.ll b/llvm/test/Transforms/FunctionAttrs/noreturn.ll
deleted file mode 100644
index 990bea984df..00000000000
--- a/llvm/test/Transforms/FunctionAttrs/noreturn.ll
+++ /dev/null
@@ -1,18 +0,0 @@
-; RUN: opt < %s -functionattrs -instcombine -S | FileCheck %s
-
-define void @endless_loop() noreturn nounwind readnone ssp uwtable {
-entry:
-  br label %while.body
-
-while.body:
-  br label %while.body
-}
-;CHECK-LABEL: @main(
-;CHECK: endless_loop
-;CHECK: ret
-define i32 @main() noreturn nounwind ssp uwtable {
-entry:
-  tail call void @endless_loop()
-  unreachable
-}
-