summaryrefslogtreecommitdiff
path: root/lib/Target/X86/README-SSE.txt
diff options
context:
space:
mode:
authorEvan Cheng <evan.cheng@apple.com>2009-01-28 08:35:02 +0000
committerEvan Cheng <evan.cheng@apple.com>2009-01-28 08:35:02 +0000
commit1632782fe9a845e545f0ebd05fb4dc304adb5bd2 (patch)
treec0fef539fd12b677df7b6e0f5cdb16e6b411ce4a /lib/Target/X86/README-SSE.txt
parentf4646d9902fcdcb121dbfbabbc2ee00bb41d7ca1 (diff)
downloadllvm-1632782fe9a845e545f0ebd05fb4dc304adb5bd2.tar.gz
llvm-1632782fe9a845e545f0ebd05fb4dc304adb5bd2.tar.bz2
llvm-1632782fe9a845e545f0ebd05fb4dc304adb5bd2.tar.xz
The memory alignment requirement on some of the mov{h|l}p{d|s} patterns are 16-byte. That is overly strict. These instructions read / write f64 memory locations without alignment requirement.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63195 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/README-SSE.txt')
-rw-r--r--lib/Target/X86/README-SSE.txt5
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Target/X86/README-SSE.txt b/lib/Target/X86/README-SSE.txt
index 7110b31487..bc51b53482 100644
--- a/lib/Target/X86/README-SSE.txt
+++ b/lib/Target/X86/README-SSE.txt
@@ -907,3 +907,8 @@ We should be able to use:
cvtsi2ss 8($esp), %xmm0
since we know the stack slot is already zext'd.
+//===---------------------------------------------------------------------===//
+
+Consider using movlps instead of movsd to implement (scalar_to_vector (loadf64))
+when code size is critical. movlps is slower than movsd on core2 but it's one
+byte shorter.