diff options
| author | Richard Sandiford <rsandifo@linux.vnet.ibm.com> | 2013-08-12 10:28:10 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@linux.vnet.ibm.com> | 2013-08-12 10:28:10 +0000 |
| commit | ac168b8bc8773a083a10902f64e4ae57a925aee4 (patch) | |
| tree | f01bc6788d39669344e52a5304fbe7859ebc8702 /lib/Target/SystemZ/README.txt | |
| parent | e03a56d62fc623e2f72d623b816f91b293d5904b (diff) | |
| download | external_llvm-ac168b8bc8773a083a10902f64e4ae57a925aee4.zip external_llvm-ac168b8bc8773a083a10902f64e4ae57a925aee4.tar.gz external_llvm-ac168b8bc8773a083a10902f64e4ae57a925aee4.tar.bz2 | |
[SystemZ] Use CLC and IPM to implement memcmp
For now this is restricted to fixed-length comparisons with a length
in the range [1, 256], as for memcpy() and MVC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188163 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/SystemZ/README.txt')
| -rw-r--r-- | lib/Target/SystemZ/README.txt | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/lib/Target/SystemZ/README.txt b/lib/Target/SystemZ/README.txt index 563513b..eebc4e4 100644 --- a/lib/Target/SystemZ/README.txt +++ b/lib/Target/SystemZ/README.txt @@ -67,12 +67,12 @@ condition codes. For example, we could use LCDFR instead of LCDBR. -- We don't optimize block memory operations, except using single MVCs -for memcpy. +for memcpy and single CLCs for memcmp. -It's definitely worth using things like CLC, NC, XC and OC with +It's definitely worth using things like NC, XC and OC with constant lengths. MVCIN may be worthwhile too. -We should probably implement things like memcpy using MVC with EXECUTE. +We should probably implement general memcpy using MVC with EXECUTE. Likewise memcmp and CLC. MVCLE and CLCLE could be useful too. -- |