Add a new attribute, 'noduplicate'. If a function contains a noduplicate call, the call cannot be duplicated - Jump threading, loop unrolling, loop unswitching, and loop rotation are inhibited if they would duplicate the call.

Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170704 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 45 insertions, 0 deletions

diff --git a/test/Transforms/Inline/basictest.ll b/test/Transforms/Inline/basictest.ll
index 609a3d4e15..39e25cb5d6 100644
--- a/test/Transforms/Inline/basictest.ll
+++ b/test/Transforms/Inline/basictest.ll
@@ -45,3 +45,48 @@ define i32 @test2(i1 %cond) {
 ; CHECK-NOT: = alloca
 ; CHECK: ret i32
 }
+
+declare void @barrier() noduplicate
+
+define internal i32 @f() {
+  call void @barrier() noduplicate
+  ret i32 1
+}
+
+define i32 @g() {
+  call void @barrier() noduplicate
+  ret i32 2
+}
+
+define internal i32 @h() {
+  call void @barrier() noduplicate
+  ret i32 3
+}
+
+define i32 @test3() {
+  %b = call i32 @f()
+  ret i32 %b
+}
+
+; The call to @f cannot be inlined as there is another callsite
+; calling @f, and @f contains a noduplicate call.
+;
+; The call to @g cannot be inlined as it has external linkage.
+;
+; The call to @h *can* be inlined.
+
+; CHECK: @test
+define i32 @test() {
+; CHECK: call i32 @f()
+  %a = call i32 @f()
+; CHECK: call i32 @g()
+  %b = call i32 @g()
+; CHECK-NOT: call i32 @h()
+  %c = call i32 @h()
+
+  %d = add i32 %a, %b
+  %e = add i32 %d, %c
+
+  ret i32 %e
+; CHECK: }
+}