diff options
| -rw-r--r-- | lib/Target/X86/README.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index a305ae6ec5..e67fab1090 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -895,6 +895,24 @@ compare: //===---------------------------------------------------------------------===// +Linux is missing some basic tail call support: + +#include <math.h> +double foo(double a) { return sin(a); } + +This compiles into this on x86-64 Linux (but not darwin): +foo: + subq $8, %rsp + call sin + addq $8, %rsp + ret +vs: + +foo: + jmp sin + +//===---------------------------------------------------------------------===// + Tail call optimization improvements: Tail call optimization currently pushes all arguments on the top of the stack (their normal place for non-tail call optimized calls) that source from the callers arguments |