For Darwin on ARMv6 and newer, make register r9 available for use as a
caller-saved register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73901 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index 7ac7b49..4aa249a 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -16,15 +16,20 @@
#include "llvm/Module.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
using namespace llvm;
+static cl::opt<bool>
+ReserveR9("arm-reserve-r9", cl::Hidden,
+ cl::desc("Reserve R9, making it unavailable as GPR"));
+
ARMSubtarget::ARMSubtarget(const Module &M, const std::string &FS,
bool isThumb)
: ARMArchVersion(V4T)
, ARMFPUType(None)
, IsThumb(isThumb)
, ThumbMode(Thumb1)
- , IsR9Reserved(false)
+ , IsR9Reserved(ReserveR9)
, stackAlignment(4)
, CPUString("generic")
, TargetType(isELF) // Default to ELF unless otherwise specified.
@@ -83,5 +88,5 @@
stackAlignment = 8;
if (isTargetDarwin())
- IsR9Reserved = true;
+ IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
}