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authorRichard Sandiford <rsandifo@linux.vnet.ibm.com>2013-09-10 12:22:45 +0000
committerRichard Sandiford <rsandifo@linux.vnet.ibm.com>2013-09-10 12:22:45 +0000
commit4c708e586eecb039811fdd54a8846002324936b2 (patch)
tree88d1e56fe286ebf8c63b3fd44531726f168adea6
parent299fdd814f4c2850d44387d24c440980c5377d3e (diff)
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[SystemZ] Update README.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190404 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Target/SystemZ/README.txt14
1 files changed, 5 insertions, 9 deletions
diff --git a/lib/Target/SystemZ/README.txt b/lib/Target/SystemZ/README.txt
index d5361fb..afa6cf0 100644
--- a/lib/Target/SystemZ/README.txt
+++ b/lib/Target/SystemZ/README.txt
@@ -58,14 +58,11 @@ condition codes. For example, we could use LCDFR instead of LCDBR.
--
-We don't optimize block memory operations, except using single MVCs
-for memcpy and single CLCs for memcmp.
+We only use MVC, XC and CLC for constant-length block operations.
+We could extend them to variable-length operations too,
+using EXECUTE RELATIVE LONG.
-It's definitely worth using things like NC, XC and OC with
-constant lengths. MVCIN may be worthwhile too.
-
-We should probably implement general memcpy using MVC with EXECUTE.
-Likewise memcmp and CLC. MVCLE and CLCLE could be useful too.
+MVCIN, MVCLE and CLCLE may be worthwhile too.
--
@@ -93,8 +90,7 @@ We don't use the halfword forms of LOAD REVERSED and STORE REVERSED
--
-We could take advantage of the various ... UNDER MASK instructions,
-such as ICM and STCM.
+We don't use ICM or STCM.
--