Perform sibcall in some cases when arguments are passes memory. Look for cases

where callee's arguments are already in the caller's own caller's stack and
they line up perfectly. e.g.

extern int foo(int a, int b, int c);

int bar(int a, int b, int c) {
  return foo(a, b, c);
}

llvm-svn: 95053

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/tailcall2.ll b/llvm/test/CodeGen/X86/tailcall2.ll
index 1e288f57651..e41e3da4f80 100644
--- a/llvm/test/CodeGen/X86/tailcall2.ll
+++ b/llvm/test/CodeGen/X86/tailcall2.ll
@@ -89,3 +89,16 @@ bb1:
 }
 
 declare i32 @bar(i32)
+
+define i32 @t7(i32 %a, i32 %b, i32 %c) nounwind ssp {
+entry:
+; 32: t7:
+; 32: jmp {{_?}}bar2
+
+; 64: t7:
+; 64: jmp {{_?}}bar2
+  %0 = tail call i32 @bar2(i32 %a, i32 %b, i32 %c) nounwind
+  ret i32 %0
+}
+
+declare i32 @bar2(i32, i32, i32)