Pull in r271548 from upstream llvm trunk (by me):

  Only attempt to detect AVG if SSE2 is available

  Summary:
  In PR29973 Sanjay Patel reported an assertion failure when a certain
  loop was optimized, for a target without SSE2 support.  It turned out
  this was because of the AVG pattern detection introduced in rL253952.

  Prevent the assertion failure by bailing out early in
  `detectAVGPattern()`, if the target does not support SSE2.

  Also add a minimized test case.

  Reviewers: congh, eli.friedman, spatel

  Subscribers: emaste, llvm-commits

  Differential Revision: http://reviews.llvm.org/D20905

This should fix assertion failures ("Requires at least SSE2!") when
building the games/0ad port with CPUTYPE=pentium3.

Reported by:	madpilot

1 files changed, 2 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Target/X86/X86ISelLowering.cpp b/contrib/llvm/lib/Target/X86/X86ISelLowering.cpp
index 25288a7..66b12d3 100644
--- a/contrib/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/contrib/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -26159,6 +26159,8 @@ static SDValue detectAVGPattern(SDValue In, EVT VT, SelectionDAG &DAG,
   if (InScalarVT.getSizeInBits() <= ScalarVT.getSizeInBits())
     return SDValue();
 
+  if (!Subtarget->hasSSE2())
+    return SDValue();
   if (Subtarget->hasAVX512()) {
     if (VT.getSizeInBits() > 512)
       return SDValue();