commit 37c2677fbcff1187106c579abfbd498aac739c2a
author Craig Topper <craig.topper@gmail.com> Tue Jan 17 04:44:50 2012 +0000
committer Craig Topper <craig.topper@gmail.com> Tue Jan 17 04:44:50 2012 +0000
tree 65225777b255e9522992789818b6b1d895e56215
parent fdebc38523b397743973ff6a2d2e93b112dd96e5

Fix a crasher when PerformShiftCombine receives a BUILD_VECTOR of all UNDEF. Probably could use better handling in DAG combine or getNode. Fixes PR11772.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148285 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86ISelLowering.cpp

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b5198c8..a0fd431 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -13430,6 +13430,11 @@
       BaseShAmt = Arg;
       break;
     }
+    // Handle the case where the build_vector is all undef
+    // FIXME: Should DAG allow this?
+    if (i == NumElts)
+      return SDValue();
+
     for (; i != NumElts; ++i) {
       SDValue Arg = ShAmtOp.getOperand(i);
       if (Arg.getOpcode() == ISD::UNDEF) continue;