[llvm-commits] [llvm] r39772 - /llvm/trunk/lib/Target/X86/README-SSE.txt

[Chris Lattner]

Author: lattner
Date: Thu Jul 12 01:31:38 2007
New Revision: 39772

URL: http://llvm.org/viewvc/llvm-project?rev=39772&view=rev
Log:
another missed SSE optimization

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

Modified: llvm/trunk/lib/Target/X86/README-SSE.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/README-SSE.txt?rev=39772&r1=39771&r2=39772&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/README-SSE.txt (original)
+++ llvm/trunk/lib/Target/X86/README-SSE.txt Thu Jul 12 01:31:38 2007
@@ -598,3 +598,32 @@
 }
 
 //===---------------------------------------------------------------------===//
+
+These functions should produce the same code:
+
+#include <emmintrin.h>
+
+typedef long long __m128i __attribute__ ((__vector_size__ (16)));
+
+int foo(__m128i* val) {
+  return __builtin_ia32_vec_ext_v4si(*val, 1);
+}
+int bar(__m128i* val) {
+  union vs {
+    __m128i *_v;
+    int* _s;
+  } v = {val};
+  return v._s[1];
+}
+
+We currently produce (with -m64):
+
+_foo:
+        pshufd $1, (%rdi), %xmm0
+        movd %xmm0, %eax
+        ret
+_bar:
+        movl 4(%rdi), %eax
+        ret
+
+//===---------------------------------------------------------------------===//