New entry.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51487 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README-SSE.txt b/lib/Target/X86/README-SSE.txt
index f200cbf11a4bc9ad63763fdddd2c7960222ad86c..7269fa2964583579690203add2888b45ad55967f 100644 (file)
--- a/lib/Target/X86/README-SSE.txt
+++ b/lib/Target/X86/README-SSE.txt
@@ -845,3 +845,47 @@ _f:
        movaps  %xmm1, %xmm0
        punpckldq       %xmm2, %xmm0
        ret
+
+//===---------------------------------------------------------------------===//
+
+We compile this:
+
+__m128i
+foo2 (char x)
+{
+  return _mm_set_epi8 (1, 0, 0, 0, 0, 0, 0, 0, 0, x, 0, 1, 0, 0, 0, 0);
+}
+
+into:
+       movl    $1, %eax
+       xorps   %xmm0, %xmm0
+       pinsrw  $2, %eax, %xmm0
+       movzbl  4(%esp), %eax
+       pinsrw  $3, %eax, %xmm0
+       movl    $256, %eax
+       pinsrw  $7, %eax, %xmm0
+       ret
+
+
+gcc-4.2:
+       subl    $12, %esp
+       movzbl  16(%esp), %eax
+       movdqa  LC0, %xmm0
+       pinsrw  $3, %eax, %xmm0
+       addl    $12, %esp
+       ret
+       .const
+       .align 4
+LC0:
+       .word   0
+       .word   0
+       .word   1
+       .word   0
+       .word   0
+       .word   0
+       .word   0
+       .word   256
+
+With SSE4, it should be
+      movdqa  .LC0(%rip), %xmm0
+      pinsrb  $6, %edi, %xmm0