From bb27da195ab212045bbaa5c453f4098eec853128 Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Mon, 26 Jan 2015 21:17:14 +0000
Subject: Pull in r226664 from upstream llvm trunk (by Tim Northover):

  AArch64: add backend option to reserve x18 (platform register)

  AAPCS64 says that it's up to the platform to specify whether x18 is
  reserved, and a first step on that way is to add a flag controlling
  it.

  From: Andrew Turner <andrew@fubar.geek.nz>

Requested by:	andrew
---
 contrib/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'contrib/llvm/lib')

diff --git a/contrib/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp b/contrib/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
index 01b9587..5112430 100644
--- a/contrib/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
+++ b/contrib/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
@@ -33,6 +33,10 @@ using namespace llvm;
 #define GET_REGINFO_TARGET_DESC
 #include "AArch64GenRegisterInfo.inc"
 
+static cl::opt<bool>
+ReserveX18("aarch64-reserve-x18", cl::Hidden,
+          cl::desc("Reserve X18, making it unavailable as GPR"));
+
 AArch64RegisterInfo::AArch64RegisterInfo(const AArch64InstrInfo *tii,
                                          const AArch64Subtarget *sti)
     : AArch64GenRegisterInfo(AArch64::LR), TII(tii), STI(sti) {}
@@ -90,7 +94,7 @@ AArch64RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
     Reserved.set(AArch64::W29);
   }
 
-  if (STI->isTargetDarwin()) {
+  if (STI->isTargetDarwin() || ReserveX18) {
     Reserved.set(AArch64::X18); // Platform register
     Reserved.set(AArch64::W18);
   }
@@ -117,7 +121,7 @@ bool AArch64RegisterInfo::isReservedReg(const MachineFunction &MF,
     return true;
   case AArch64::X18:
   case AArch64::W18:
-    return STI->isTargetDarwin();
+    return STI->isTargetDarwin() || ReserveX18;
   case AArch64::FP:
   case AArch64::W29:
     return TFI->hasFP(MF) || STI->isTargetDarwin();
@@ -379,7 +383,7 @@ unsigned AArch64RegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
   case AArch64::GPR64commonRegClassID:
     return 32 - 1                                      // XZR/SP
            - (TFI->hasFP(MF) || STI->isTargetDarwin()) // FP
-           - STI->isTargetDarwin() // X18 reserved as platform register
+           - (STI->isTargetDarwin() || ReserveX18) // X18 reserved as platform register
            - hasBasePointer(MF);   // X19
   case AArch64::FPR8RegClassID:
   case AArch64::FPR16RegClassID:
-- 
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