Avoid copies of std::strings and APInt/APFloats where we only read from it

As suggested by clang-tidy's performance-unnecessary-copy-initialization.
This can easily hit lifetime issues, so I audited every change and ran the
tests under asan, which came back clean.

llvm-svn: 272126

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/Hexagon/BitTracker.cpp b/llvm/lib/Target/Hexagon/BitTracker.cpp
index 1c4347e7126..724c9b60898 100644
--- a/llvm/lib/Target/Hexagon/BitTracker.cpp
+++ b/llvm/lib/Target/Hexagon/BitTracker.cpp
@@ -422,7 +422,7 @@ BT::RegisterCell BT::MachineEvaluator::eIMM(int64_t V, uint16_t W) const {
 
 
 BT::RegisterCell BT::MachineEvaluator::eIMM(const ConstantInt *CI) const {
-  APInt A = CI->getValue();
+  const APInt &A = CI->getValue();
   uint16_t BW = A.getBitWidth();
   assert((unsigned)BW == A.getBitWidth() && "BitWidth overflow");
   RegisterCell Res(BW);