[ARM] Define subtarget feature reserve-r9

[ahatanak]

Summary

In this patch, subtarget feature reserve-r9 is defined. ARMSubtarget::isR9Reserved uses this feature instead of cl::opt option "arm-reserve-r9" to decide whether register r9 should be reserved.

[MatzeB]

LGTM

lib/Target/ARM/ARM.td

 // See ARMInstrInfo.td for details.
 def FeatureNaClTrap : SubtargetFeature<"nacl-trap", "UseNaClTrap", "true",
                                        "NaCl trap">;
 
 def FeatureLongCalls : SubtargetFeature<"long-calls", "GenLongCalls", "true",
                                         "Generate calls via indirect call "
                                         "instructions">;
 
+def FeatureReserveR9 : SubtargetFeature<"reserve-r9", "ReserveR9", "true",
+                                        "Reserve R9, making it unavailable as "
+                                        "GPR">;
+
 def FeatureNoMovt : SubtargetFeature<"no-movt", "NoMovt", "true",
                                      "Don't use movt/movw pairs for 32-bit "
                                      "imms">;
 
 // ARM ISAs.
 def HasV4TOps   : SubtargetFeature<"v4t", "HasV4TOps", "true",
                                    "Support ARM v4T instructions">;
 def HasV5TOps   : SubtargetFeature<"v5t", "HasV5TOps", "true",

lib/Target/ARM/ARMSubtarget.h

protected:
   bool UseSoftFloat;
 
   /// HasThumb2 - True if Thumb2 instructions are supported.
   bool HasThumb2;
 
   /// NoARM - True if subtarget does not support ARM mode execution.
   bool NoARM;
 
-  /// IsR9Reserved - True if R9 is a not available as general purpose register.
-  bool IsR9Reserved;
+  /// ReserveR9 - True if R9 is not available as a general purpose register.
+  bool ReserveR9;
 
   /// NoMovt - True if MOVT / MOVW pairs are not used for materialization of
   /// 32-bit imms (including global addresses).
   bool NoMovt;
 
   /// SupportsTailCall - True if the OS supports tail call. The dynamic linker
   /// must be able to synthesize call stubs for interworking between ARM and
   /// Thumb.
public:
   bool isMClass() const { return ARMProcClass == MClass; }
   bool isRClass() const { return ARMProcClass == RClass; }
   bool isAClass() const { return ARMProcClass == AClass; }
 
   bool isV6M() const {
     return isThumb1Only() && isMClass();
   }
 
-  bool isR9Reserved() const { return IsR9Reserved; }
+  bool isR9Reserved() const {
+    return isTargetMachO() ? (ReserveR9 || !HasV6Ops) : ReserveR9;
+  }
 
   bool useMovt(const MachineFunction &MF) const;
 
   bool supportsTailCall() const { return SupportsTailCall; }
 
   bool allowsUnalignedMem() const { return AllowsUnalignedMem; }
 
   bool restrictIT() const { return RestrictIT; }

lib/Target/ARM/ARMSubtarget.cpp

 
 #define DEBUG_TYPE "arm-subtarget"
 
 #define GET_SUBTARGETINFO_TARGET_DESC
 #define GET_SUBTARGETINFO_CTOR
 #include "ARMGenSubtargetInfo.inc"
 
 static cl::opt<bool>
-ReserveR9("arm-reserve-r9", cl::Hidden,
-          cl::desc("Reserve R9, making it unavailable as GPR"));
-
-static cl::opt<bool>
 UseFusedMulOps("arm-use-mulops",
                cl::init(true), cl::Hidden);
 
 namespace {
 enum AlignMode {
   DefaultAlign,
   StrictAlign,
   NoStrictAlign
void ARMSubtarget::initializeEnvironment() {
   UseMulOps = UseFusedMulOps;
   SlowFPVMLx = false;
   HasVMLxForwarding = false;
   SlowFPBrcc = false;
   InThumbMode = false;
   UseSoftFloat = false;
   HasThumb2 = false;
   NoARM = false;
-  IsR9Reserved = ReserveR9;
+  ReserveR9 = false;
   NoMovt = false;
   SupportsTailCall = false;
   HasFP16 = false;
   HasD16 = false;
   HasHardwareDivide = false;
   HasHardwareDivideInARM = false;
   HasT2ExtractPack = false;
   HasDataBarrier = false;
void ARMSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
   if (isTargetWindows())
     NoARM = true;
 
   if (isAAPCS_ABI())
     stackAlignment = 8;
   if (isTargetNaCl())
     stackAlignment = 16;
 
-  if (isTargetMachO()) {
-    IsR9Reserved = ReserveR9 || !HasV6Ops;
+  if (isTargetMachO())
     SupportsTailCall = !isTargetIOS() || !getTargetTriple().isOSVersionLT(5, 0);
-  } else {
-    IsR9Reserved = ReserveR9;
+  else
     SupportsTailCall = !isThumb1Only();
-  }
 
   if (Align == DefaultAlign) {
     // Assume pre-ARMv6 doesn't support unaligned accesses.
     //
     // ARMv6 may or may not support unaligned accesses depending on the
     // SCTLR.U bit, which is architecture-specific. We assume ARMv6
     // Darwin and NetBSD targets support unaligned accesses, and others don't.
     //

test/CodeGen/ARM/2007-03-13-InstrSched.ll

 ; REQUIRES: asserts
 ; RUN: llc < %s -mtriple=arm-apple-darwin -relocation-model=pic \
 ; RUN:   -mattr=+v6 | grep r9
 ; RUN: llc < %s -mtriple=arm-apple-darwin -relocation-model=pic \
-; RUN:   -mattr=+v6 -arm-reserve-r9 -ifcvt-limit=0 -stats 2>&1 | grep asm-printer
+; RUN:   -mattr=+v6,+reserve-r9 -ifcvt-limit=0 -stats 2>&1 | grep asm-printer
 ; | grep 35
 
 define void @test(i32 %tmp56222, i32 %tmp36224, i32 %tmp46223, i32 %i.0196.0.ph, i32 %tmp8, i32* %tmp1011, i32** %tmp1, i32* %d2.1.out, i32* %d3.1.out, i32* %d0.1.out, i32* %d1.1.out) {
 newFuncRoot:
   br label %bb74
 
 bb78.exitStub:    ; preds = %bb74
   store i32 %d2.1, i32* %d2.1.out

test/CodeGen/ARM/build-attributes.ll

 ; RUN: llc < %s -mtriple=armv7-none-linux-gnueabi -mcpu=cortex-a7 -mattr=+vfp4,-neon  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-A7-FPUV4-FAST
 ; RUN: llc < %s -mtriple=armv7-none-linux-gnueabi -mcpu=cortex-a7 -mattr=+vfp4,,+d16,-neon | FileCheck %s --check-prefix=CORTEX-A7-FPUV4
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=pic | FileCheck %s --check-prefix=RELOC-PIC
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=static | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=default | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=dynamic-no-pic | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi | FileCheck %s --check-prefix=PCS-R9-USE
-; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -arm-reserve-r9 | FileCheck %s --check-prefix=PCS-R9-RESERVE
+; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -mattr=+reserve-r9 | FileCheck %s --check-prefix=PCS-R9-RESERVE
 
 ; ARMv8.1a (AArch32)
 ; RUN: llc < %s -mtriple=armv8.1a-none-linux-gnueabi -arm-no-strict-align | FileCheck %s --check-prefix=NO-STRICT-ALIGN
 ; RUN: llc < %s -mtriple=armv8.1a-none-linux-gnueabi -arm-strict-align | FileCheck %s --check-prefix=STRICT-ALIGN
 ; RUN: llc < %s -mtriple=armv8.1a-none-linux-gnueabi | FileCheck %s --check-prefix=NO-STRICT-ALIGN
 ; ARMv8a (AArch32)
 ; RUN: llc < %s -mtriple=armv8-none-linux-gnueabi -mcpu=cortex-a57 -arm-no-strict-align | FileCheck %s --check-prefix=NO-STRICT-ALIGN
 ; RUN: llc < %s -mtriple=armv8-none-linux-gnueabi -mcpu=cortex-a57 -arm-strict-align | FileCheck %s --check-prefix=STRICT-ALIGN