[GISel]: Fix undefined behavior while accessing DefaultAction map
We end up dereferencing the end iterator here when the Aspect doesn't exist in the DefaultAction map.
Change the API to return Optional<LLT> and return None when not found.
Also update the callers to handle the None case
llvm-svn: 302963
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
index 718d2c7..4d45910 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -162,7 +162,7 @@
return std::get<0>(getAction(MI, MRI)) == Legal;
}
-LLT LegalizerInfo::findLegalType(const InstrAspect &Aspect,
+Optional<LLT> LegalizerInfo::findLegalType(const InstrAspect &Aspect,
LegalizeAction Action) const {
switch(Action) {
default: