[llvm-commits] [llvm] r59052 - /llvm/trunk/lib/Target/X86/README.txt

[Evan Cheng]

Author: evancheng
Date: Tue Nov 11 11:35:52 2008
New Revision: 59052

URL: http://llvm.org/viewvc/llvm-project?rev=59052&view=rev
Log:
Add a README entry.

Modified:
    llvm/trunk/lib/Target/X86/README.txt

Modified: llvm/trunk/lib/Target/X86/README.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/README.txt?rev=59052&r1=59051&r2=59052&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/README.txt (original)
+++ llvm/trunk/lib/Target/X86/README.txt Tue Nov 11 11:35:52 2008
@@ -1773,3 +1773,20 @@
         movl    12(%ebp), %eax
         popl    %ebp
         ret
+
+//===---------------------------------------------------------------------===//
+
+Teach tblgen not to check bitconvert source type in some cases. This allows us
+to consolidate the following patterns in X86InstrMMX.td:
+
+def : Pat<(v2i32 (bitconvert (i64 (vector_extract (v2i64 VR128:$src),
+                                                  (iPTR 0))))),
+          (v2i32 (MMX_MOVDQ2Qrr VR128:$src))>;
+def : Pat<(v4i16 (bitconvert (i64 (vector_extract (v2i64 VR128:$src),
+                                                  (iPTR 0))))),
+          (v4i16 (MMX_MOVDQ2Qrr VR128:$src))>;
+def : Pat<(v8i8 (bitconvert (i64 (vector_extract (v2i64 VR128:$src),
+                                                  (iPTR 0))))),
+          (v8i8 (MMX_MOVDQ2Qrr VR128:$src))>;
+
+There are other cases in various td files.