[DAGCombine] Disable select(c, load,load) for indexed loads
This turned up after r235333, but was a pre-existing bug. The optimization
which transforms select(c, load, load) into a load of a select of the addresses
does not handle indexed loads (pre/post inc/dec). However, it did not check for
them either, leading to a crash if it tried to transform one of them.
llvm-svn: 235497
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 1179b76..4b98da7 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12799,6 +12799,9 @@
if (LHS.getOperand(0) != RHS.getOperand(0) ||
// Do not let this transformation reduce the number of volatile loads.
LLD->isVolatile() || RLD->isVolatile() ||
+ // FIXME: If either is a pre/post inc/dec load,
+ // we'd need to split out the address adjustment.
+ LLD->isIndexed() || RLD->isIndexed() ||
// If this is an EXTLOAD, the VT's must match.
LLD->getMemoryVT() != RLD->getMemoryVT() ||
// If this is an EXTLOAD, the kind of extension must match.