GlobalISel: stop the legalizer from trying to handle oddly-sized types.

It'll almost immediately fail because it always tries to half/double the size
until it finds a legal one. Unfortunately, this triggers an assertion
preventing the DAG fallback from being possible.

llvm-svn: 288834

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
index ebbed12943b..2b99a555858 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -71,6 +71,11 @@ LegalizerInfo::getAction(const InstrAspect &Aspect) const {
   // These *have* to be implemented for now, they're the fundamental basis of
   // how everything else is transformed.
 
+  // Nothing is going to go well with types that aren't a power of 2 yet, so
+  // don't even try because we might make things worse.
+  if (!isPowerOf2_64(Aspect.Type.getSizeInBits()))
+      return std::make_pair(Unsupported, LLT());
+
   // FIXME: the long-term plan calls for expansion in terms of load/store (if
   // they're not legal).
   if (Aspect.Opcode == TargetOpcode::G_SEQUENCE ||