[CXX_FAST_TLS] fix issues with O0 on ARM, AArch64 and X86.
Since at O0, explicit copies via SplitCSR may not be removed even if
they are unnecessary, we choose not to use SplitCSR at O0.
llvm-svn: 263855
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 1a0c902..8c0ff29 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -473,7 +473,7 @@
// We split CSR if the target supports it for the given function
// and the function has only return exits.
- if (TLI->supportSplitCSR(MF)) {
+ if (OptLevel != CodeGenOpt::None && TLI->supportSplitCSR(MF)) {
FuncInfo->SplitCSR = true;
// Collect all the return blocks.