commit aadc688c8ea8a869f7ef4c260208c9d532d26dc3
author Craig Topper <craig.topper@intel.com> Tue Oct 15 06:10:11 2019 +0000
committer Craig Topper <craig.topper@intel.com> Tue Oct 15 06:10:11 2019 +0000
tree cb356b8539f1c8ec399a8e8856fdca4d1c2fd559
parent 75cbca09a42dd2ea9f38d8f4bb4c3f3630ebade5

[X86] Don't check for VBROADCAST_LOAD being a user of the source of a VBROADCAST when trying to share broadcasts.

The only things VBROADCAST_LOAD uses is an address and a chain
node. It has no vector inputs.

So if its a user of the source of another broadcast that could
only mean one of two things. The other broadcast is broadcasting
the address of the broadcast_load. Or the source is a load and
the use we're seeing is the chain result from that load. Neither
of these cases make sense to combine here.

This issue was reported post-commit r373871. Test case has not
been reduced yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374862 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 c649a90..0e5a397 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -33450,9 +33450,7 @@
 
     // Share broadcast with the longest vector and extract low subvector (free).
     for (SDNode *User : Src->uses())
-      if (User != N.getNode() &&
-          (User->getOpcode() == X86ISD::VBROADCAST ||
-           User->getOpcode() == X86ISD::VBROADCAST_LOAD) &&
+      if (User != N.getNode() && User->getOpcode() == X86ISD::VBROADCAST &&
           User->getValueSizeInBits(0) > VT.getSizeInBits()) {
         return extractSubVector(SDValue(User, 0), 0, DAG, DL,
                                 VT.getSizeInBits());