Another entry about shuffles.

llvm-svn: 27245
2006-03-29 03:03:46 +00:00 · 2006-03-29 03:03:46 +00:00 · 3a1c4e75de
parent da59b0d2a8
commit 3a1c4e75de
1 changed files with 6 additions and 0 deletions
--- a/llvm/lib/Target/X86/README.txt
+++ b/llvm/lib/Target/X86/README.txt
@ -667,3 +667,9 @@ directly %esp[0] if there are no other uses.

 Use movhps to update upper 64-bits of a v4sf value. Also movlps on lower half
 of a v4sf value.
+
+//===---------------------------------------------------------------------===//
+
+Better codegen for vector_shuffles like this { x, 0, 0, 0 } or { x, 0, x, 0}.
+Perhaps use pxor / xorp* to clear a XMM register first?
+