add some notes and a file to collect unimplemented features in the

x86 backend.  These will all be answered with "patches welcome", so
a PR doesn't help drive them along.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57630 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README-UNIMPLEMENTED.txt b/lib/Target/X86/README-UNIMPLEMENTED.txt
new file mode 100644 (file)
index 0000000..b9ba493
--- /dev/null
+++ b/lib/Target/X86/README-UNIMPLEMENTED.txt
@@ -0,0 +1,14 @@
+//===---------------------------------------------------------------------===//
+// Testcases that crash the X86 backend because they aren't implemented
+//===---------------------------------------------------------------------===//
+
+These are cases we know the X86 backend doesn't handle.  Patches are welcome
+and appreciated, because no one has signed up to implemented these yet.
+Implementing these would allow elimination of the corresponding intrinsics,
+which would be great.
+
+1) vector shifts
+2) vector comparisons
+3) vector fp<->int comparisons: PR2683, PR2684, PR2685, PR2686, PR2688
+
+