commit efd72857a341d62a344dbeaf8baae56454ea4437
author Krzysztof Parzyszek <kparzysz@codeaurora.org> Thu Apr 28 15:09:19 2016 +0000
committer Krzysztof Parzyszek <kparzysz@codeaurora.org> Thu Apr 28 15:09:19 2016 +0000
tree 0e816c638243af3c631f7f9085836d30a3f82697
parent 354fac2a69574ac668c3f7d56ca22f7c9aa91344

[RDF] Handle undefined registers in RDF copy propagation

When updating the graph, make sure that new uses without reaching defs
are handled correctly.

llvm-svn: 267891

llvm/lib/Target/Hexagon/RDFCopy.cpp

diff --git a/llvm/lib/Target/Hexagon/RDFCopy.cpp b/llvm/lib/Target/Hexagon/RDFCopy.cpp
index 251e175..c777878 100644
--- a/llvm/lib/Target/Hexagon/RDFCopy.cpp
+++ b/llvm/lib/Target/Hexagon/RDFCopy.cpp
@@ -218,7 +218,12 @@
         Op.setReg(SR.Reg);
         Op.setSubReg(SR.Sub);
         DFG.unlinkUse(UA, false);
-        UA.Addr->linkToDef(UA.Id, DFG.addr<DefNode*>(RDefSR_SA));
+        if (RDefSR_SA != 0) {
+          UA.Addr->linkToDef(UA.Id, DFG.addr<DefNode*>(RDefSR_SA));
+        } else {
+          UA.Addr->setReachingDef(0);
+          UA.Addr->setSibling(0);
+        }
 
         Changed = true;
   #ifndef NDEBUG