Imported Upstream version 5.18.0.246

Former-commit-id: 0c7ce5b1a7851e13f22acfd379b7f9fb304e4833

external/llvm/test/Transforms/MergeFunc/fold-weak.ll

@@ -0,0 +1,47 @@
+; RUN: opt -S -mergefunc < %s | FileCheck %s
+
+define weak i32 @sum(i32 %x, i32 %y) {
+  %sum = add i32 %x, %y
+  %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
+  %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
+}