From 6256c0168591c356dcd01858cee1e08f06699ff9 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Mon, 25 Sep 2017 22:00:17 +0000
Subject: [PATCH] X86: remove R12 from CSR on Windows x64 SwiftCC

R12 is used for the SwiftError parameter.  It is no longer a CSR as it
is used for transfer the SwiftError, and the caller must preserve it if
they need to.

llvm-svn: 314165
---
 lib/Target/X86/X86CallingConv.td   |  2 ++
 lib/Target/X86/X86RegisterInfo.cpp | 39 +++++++++++++++---------------
 test/CodeGen/X86/swift-error.ll    |  4 +--
 3 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td
index 64c81391578..2de9a5fbfe9 100644
--- a/lib/Target/X86/X86CallingConv.td
+++ b/lib/Target/X86/X86CallingConv.td
@@ -1050,6 +1050,8 @@ def CSR_Win64_NoSSE : CalleeSavedRegs<(add RBX, RBP, RDI, RSI, R12, R13, R14, R1
 def CSR_Win64 : CalleeSavedRegs<(add CSR_Win64_NoSSE,
                                      (sequence "XMM%u", 6, 15))>;
 
+def CSR_Win64_SwiftError : CalleeSavedRegs<(sub CSR_Win64, R12)>;
+
 // The function used by Darwin to obtain the address of a thread-local variable
 // uses rdi to pass a single parameter and rax for the return value. All other
 // GPRs are preserved.
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 343da2573b5..1f49650340e 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -271,12 +271,13 @@ X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   assert(MF && "MachineFunction required");
 
   const X86Subtarget &Subtarget = MF->getSubtarget<X86Subtarget>();
+  const Function *F = MF->getFunction();
   bool HasSSE = Subtarget.hasSSE1();
   bool HasAVX = Subtarget.hasAVX();
   bool HasAVX512 = Subtarget.hasAVX512();
   bool CallsEHReturn = MF->callsEHReturn();
 
-  CallingConv::ID CC = MF->getFunction()->getCallingConv();
+  CallingConv::ID CC = F->getCallingConv();
 
   // If attribute NoCallerSavedRegisters exists then we set X86_INTR calling
   // convention because it has the CSR list.
@@ -365,22 +366,20 @@ X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   }
 
   if (Is64Bit) {
-    if (IsWin64) {
-      if (!HasSSE)
-        return CSR_Win64_NoSSE_SaveList;
-      return CSR_Win64_SaveList;
-    }
+    bool IsSwiftCC = Subtarget.getTargetLowering()->supportSwiftError() &&
+                     F->getAttributes().hasAttrSomewhere(Attribute::SwiftError);
+    if (IsSwiftCC)
+      return IsWin64 ? CSR_Win64_SwiftError_SaveList
+                     : CSR_64_SwiftError_SaveList;
+
+    if (IsWin64)
+      return HasSSE ? CSR_Win64_SaveList : CSR_Win64_NoSSE_SaveList;
     if (CallsEHReturn)
       return CSR_64EHRet_SaveList;
-    if (Subtarget.getTargetLowering()->supportSwiftError() &&
-        MF->getFunction()->getAttributes().hasAttrSomewhere(
-            Attribute::SwiftError))
-      return CSR_64_SwiftError_SaveList;
     return CSR_64_SaveList;
   }
-  if (CallsEHReturn)
-    return CSR_32EHRet_SaveList;
-  return CSR_32_SaveList;
+
+  return CallsEHReturn ? CSR_32EHRet_SaveList : CSR_32_SaveList;
 }
 
 const MCPhysReg *X86RegisterInfo::getCalleeSavedRegsViaCopy(
@@ -479,14 +478,14 @@ X86RegisterInfo::getCallPreservedMask(const MachineFunction &MF,
   // Unlike getCalleeSavedRegs(), we don't have MMI so we can't check
   // callsEHReturn().
   if (Is64Bit) {
-    if (IsWin64)
-      return CSR_Win64_RegMask;
-    if (Subtarget.getTargetLowering()->supportSwiftError() &&
-        MF.getFunction()->getAttributes().hasAttrSomewhere(
-            Attribute::SwiftError))
-      return CSR_64_SwiftError_RegMask;
-    return CSR_64_RegMask;
+    const Function *F = MF.getFunction();
+    bool IsSwiftCC = Subtarget.getTargetLowering()->supportSwiftError() &&
+                     F->getAttributes().hasAttrSomewhere(Attribute::SwiftError);
+    if (IsSwiftCC)
+      return IsWin64 ? CSR_Win64_SwiftError_RegMask : CSR_64_SwiftError_RegMask;
+    return IsWin64 ? CSR_Win64_RegMask : CSR_64_RegMask;
   }
+
   return CSR_32_RegMask;
 }
 
diff --git a/test/CodeGen/X86/swift-error.ll b/test/CodeGen/X86/swift-error.ll
index 5fb67d4f3b2..896166a369e 100644
--- a/test/CodeGen/X86/swift-error.ll
+++ b/test/CodeGen/X86/swift-error.ll
@@ -11,8 +11,8 @@ entry:
 }
 
 ; CHECK-LABEL: g
-; CHECK: pushq   %r12
+; CHECK-NOT: pushq   %r12
 ; CHECK: callq   f
-; CHECK: popq    %r12
+; CHECK-NOT: popq    %r12
 ; CHECK: retq