MergeFunctions: Don't replace a weak function use by another equivalent weak function

We don't know whether the weak functions definition is the definitive definition.

rdar://21303727

llvm-svn: 239422

1 files changed, 39 insertions, 9 deletions

diff --git a/llvm/test/Transforms/MergeFunc/fold-weak.ll b/llvm/test/Transforms/MergeFunc/fold-weak.ll
index 4df6e39c125..f8a18887890 100644
--- a/llvm/test/Transforms/MergeFunc/fold-weak.ll
+++ b/llvm/test/Transforms/MergeFunc/fold-weak.ll
@@ -1,17 +1,47 @@
-; RUN: opt < %s -mergefunc -S > %t
-; RUN: grep "define weak" %t | count 2
-; RUN: grep "call" %t | count 2
-; XFAIL: *
-
-; This test is off for a bit as we change this particular sort of folding to
-; only apply on ELF systems and not Mach-O systems.
+; RUN: opt -S -mergefunc < %s | FileCheck %s
 
 define weak i32 @sum(i32 %x, i32 %y) {
   %sum = add i32 %x, %y
-  ret i32 %sum
+  %sum2 = add i32 %sum, %y
+  %sum3 = add i32 %sum2, %y
+  ret i32 %sum3
 }
 
 define weak i32 @add(i32 %x, i32 %y) {
   %sum = add i32 %x, %y
-  ret i32 %sum
+  %sum2 = add i32 %sum, %y
+  %sum3 = add i32 %sum2, %y
+  ret i32 %sum3
+}
+
+; Don't replace a weak function use by another equivalent function. We don't
+; know whether the symbol that will ulitmately be linked is equivalent - we
+; don't know that the weak definition is the definitive definition or whether it
+; will be overriden by a stronger definition).
+
+; CHECK-LABEL: define private i32 @0
+; CHECK: add i32
+; CHECK: add i32
+; CHECK: add i32
+; CHECK: ret
+
+; CHECK-LABEL: define i32 @use_weak
+; CHECK: call i32 @add
+; CHECK: call i32 @sum
+; CHECK: ret
+
+; CHECK-LABEL: define weak i32 @sum
+; CHECK:  tail call i32 @0
+; CHECK:  ret
+
+; CHECK-LABEL: define weak i32 @add
+; CHECK:  tail call i32 @0
+; CHECK:  ret
+
+
+define i32 @use_weak(i32 %a, i32 %b) {
+  %res = call i32 @add(i32 %a, i32 %b)
+  %res2 = call i32 @sum(i32 %a, i32 %b)
+  %res3 = add i32 %res, %res2
+  ret i32 %res3
 }