[FunctionAttrs] Precommit tests for willreturn inference.

Tests for D94502.

Author: fhahn

llvm/test/Transforms/FunctionAttrs/willreturn.ll

@@ -0,0 +1,72 @@
+; RUN: opt -function-attrs -S %s | FileCheck %s
+
+; TODO
+define void @mustprogress_readnone() mustprogress {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK:     define void @mustprogress_readnone()
+;
+entry:
+  br label %while.body
+
+while.body:
+  br label %while.body
+}
+
+; TODO
+define i32 @mustprogress_load(i32* %ptr) mustprogress {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK:     define i32 @mustprogress_load(
+;
+entry:
+  %r = load i32, i32* %ptr
+  ret i32 %r
+}
+
+define void @mustprogress_store(i32* %ptr) mustprogress {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK: define void @mustprogress_store(
+;
+entry:
+  store i32 0, i32* %ptr
+  ret void
+}
+
+declare void @unknown_fn()
+
+define void @mustprogress_call_unknown_fn() mustprogress {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK: define void @mustprogress_call_unknown_fn(
+;
+  call void @unknown_fn()
+  ret void
+}
+
+; TODO
+define i32 @mustprogress_call_known_functions(i32* %ptr) mustprogress {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK:     define i32 @mustprogress_call_known_functions(
+;
+  call void @mustprogress_readnone()
+  %r = call i32 @mustprogress_load(i32* %ptr)
+  ret i32 %r
+}
+
+declare i32 @__gxx_personality_v0(...)
+
+; TODO
+define i64 @mustprogress_mayunwind() mustprogress personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-NOT: Function Attrs: {{.*}} willreturn
+; CHECK:     define i64 @mustprogress_mayunwind(
+;
+  %a = invoke i64 @fn_noread()
+          to label %A unwind label %B
+A:
+  ret i64 10
+
+B:
+  %val = landingpad { i8*, i32 }
+           catch i8* null
+  ret i64 0
+}
+
+declare i64 @fn_noread() readnone