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| author | Chris Lattner <sabre@nondot.org> | 2010-11-21 18:59:20 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-11-21 18:59:20 +0000 |
| commit | 8bc1e4529528a22c16dc7803951a91fafbde11bb (patch) | |
| tree | 6430e630eeb4e52d9a31c76d706e355287b83e5c /lib/Target/X86/README.txt | |
| parent | dd061b28548434579e8547aa7aed83f78741ae6f (diff) | |
| download | llvm-8bc1e4529528a22c16dc7803951a91fafbde11bb.tar.gz llvm-8bc1e4529528a22c16dc7803951a91fafbde11bb.tar.bz2 llvm-8bc1e4529528a22c16dc7803951a91fafbde11bb.tar.xz | |
apparently tailcalls are better on darwin/x86-64 than on linux?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119947 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/README.txt')
| -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 |