[llvm-commits] CVS: llvm/lib/Target/X86/README.txt

[Evan Cheng]

Changes in directory llvm/lib/Target/X86:

README.txt updated: 1.98 -> 1.99
---
Log message:

A couple of new entries.


---
Diffs of the changes:  (+37 -0)

 README.txt |   37 +++++++++++++++++++++++++++++++++++++
 1 files changed, 37 insertions(+)


Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.98 llvm/lib/Target/X86/README.txt:1.99
--- llvm/lib/Target/X86/README.txt:1.98	Mon Apr 24 18:30:10 2006
+++ llvm/lib/Target/X86/README.txt	Thu Apr 27 03:31:33 2006
@@ -1107,3 +1107,40 @@
 
 So icc is smart enough to know that B is in memory so it doesn't load it and
 store it back to stack.
+
+//===---------------------------------------------------------------------===//
+
+__m128d test1( __m128d A, __m128d B) {
+  return _mm_shuffle_pd(A, B, 0x3);
+}
+
+compiles to
+
+shufpd $3, %xmm1, %xmm0
+
+Perhaps it's better to use unpckhpd instead?
+
+unpckhpd %xmm1, %xmm0
+
+Don't know if unpckhpd is faster. But it is shorter.
+
+//===---------------------------------------------------------------------===//
+
+typedef short  v8i16 __attribute__ ((__vector_size__ (16)));
+v8i16 test(v8i16 x, v8i16 y) {
+  return x + y;
+}
+
+compiles to
+
+_test:
+	paddw %xmm0, %xmm1
+	movaps %xmm1, %xmm0
+	ret
+
+It should be
+
+	paddw %xmm1, %xmm0
+	ret
+
+since paddw is commutative.