Imported Upstream version 5.18.0.205

Former-commit-id: 7f59f7e792705db773f1caecdaa823092f4e2927

external/llvm/test/Transforms/DeadArgElim/deadretval2.ll

@@ -0,0 +1,59 @@
+; RUN: opt < %s -deadargelim -die -S > %t
+; RUN: cat %t | not grep DEAD
+; RUN: cat %t | grep LIVE | count 4
+
+@P = external global i32                ; <i32*> [#uses=1]
+
+; Dead arg only used by dead retval
+define internal i32 @test(i32 %DEADARG) {
+        ret i32 %DEADARG
+}
+
+define internal i32 @test2(i32 %DEADARG) {
+        %DEADRETVAL = call i32 @test( i32 %DEADARG )            ; <i32> [#uses=1]
+        ret i32 %DEADRETVAL
+}
+
+define void @test3(i32 %X) {
+        %DEADRETVAL = call i32 @test2( i32 %X )         ; <i32> [#uses=0]
+        ret void
+}
+
+define internal i32 @foo() {
+        %DEAD = load i32, i32* @P            ; <i32> [#uses=1]
+        ret i32 %DEAD
+}
+
+define internal i32 @id(i32 %X) {
+        ret i32 %X
+}
+
+define void @test4() {
+        %DEAD = call i32 @foo( )                ; <i32> [#uses=1]
+        %DEAD2 = call i32 @id( i32 %DEAD )              ; <i32> [#uses=0]
+        ret void
+}
+
+; These test if returning another functions return value properly marks that
+; other function's return value as live. We do this twice, with the functions in
+; different orders (ie, first the caller, than the callee and first the callee
+; and then the caller) since DAE processes functions one by one and handles
+; these cases slightly different.
+
+define internal i32 @test5() {
+  ret i32 123 
+}
+
+define i32 @test6() {
+  %LIVE = call i32 @test5()
+  ret i32 %LIVE
+}
+
+define i32 @test7() {
+  %LIVE = call i32 @test8()
+  ret i32 %LIVE
+}
+
+define internal i32 @test8() {
+  ret i32 124
+}