From 228232b2821f8e7f9c0b874ad733414bda183db6 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@apple.com>
Date: Tue, 30 Nov 2010 07:20:12 +0000
Subject: [PATCH] Rewrite mwait and monitor support and custom lower arguments.

Fixes PR8573.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120404 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp | 53 ++++++++++++++++++++++++++++++
 lib/Target/X86/X86ISelLowering.h   |  7 ++++
 lib/Target/X86/X86InstrSSE.td      | 19 ++++++++---
 test/CodeGen/X86/apm.ll            | 26 +++++++++++++++
 4 files changed, 101 insertions(+), 4 deletions(-)
 create mode 100644 test/CodeGen/X86/apm.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 6793b70dd57..f53b0ed3834 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -9443,6 +9443,53 @@ X86TargetLowering::EmitPCMP(MachineInstr *MI, MachineBasicBlock *BB,
   return BB;
 }
 
+MachineBasicBlock *
+X86TargetLowering::EmitMonitor(MachineInstr *MI, MachineBasicBlock *BB) const {
+  assert((Subtarget->hasSSE3()) && "Target must have SSE3 features enabled");
+  
+  DebugLoc dl = MI->getDebugLoc();
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  
+  // Address into RAX/EAX, other two args into ECX, EDX.
+  unsigned MemOpc = Subtarget->is64Bit() ? X86::LEA64r : X86::LEA32r;
+  unsigned MemReg = Subtarget->is64Bit() ? X86::RAX : X86::EAX;
+  MachineInstrBuilder MIB = BuildMI(*BB, MI, dl, TII->get(MemOpc), MemReg);
+  for (int i = 0; i < X86::AddrNumOperands; ++i)
+    (*MIB).addOperand(MI->getOperand(i));
+  
+  unsigned ValOps = X86::AddrNumOperands;
+  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::ECX)
+    .addReg(MI->getOperand(ValOps).getReg());
+  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::EDX)
+    .addReg(MI->getOperand(ValOps+1).getReg());
+
+  // The instruction doesn't actually take any operands though.
+  BuildMI(*BB, MI, dl, TII->get(X86::MONITORrrr));
+  
+  MI->eraseFromParent(); // The pseudo is gone now.
+  return BB;
+}
+
+MachineBasicBlock *
+X86TargetLowering::EmitMwait(MachineInstr *MI, MachineBasicBlock *BB) const {
+  assert((Subtarget->hasSSE3()) && "Target must have SSE3 features enabled");
+  
+  DebugLoc dl = MI->getDebugLoc();
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  
+  // First arg in ECX, the second in EAX.
+  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::ECX)
+    .addReg(MI->getOperand(0).getReg());
+  BuildMI(*BB, MI, dl, TII->get(TargetOpcode::COPY), X86::EAX)
+    .addReg(MI->getOperand(1).getReg());
+    
+  // The instruction doesn't actually take any operands though.
+  BuildMI(*BB, MI, dl, TII->get(X86::MWAITrr));
+  
+  MI->eraseFromParent(); // The pseudo is gone now.
+  return BB;
+}
+
 MachineBasicBlock *
 X86TargetLowering::EmitVAARG64WithCustomInserter(
                    MachineInstr *MI,
@@ -10042,6 +10089,12 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
   case X86::VPCMPESTRM128MEM:
     return EmitPCMP(MI, BB, 5, true /* in mem */);
 
+    // Thread synchronization.
+  case X86::MONITOR:
+    return EmitMonitor(MI, BB);  
+  case X86::MWAIT:
+    return EmitMwait(MI, BB);
+
     // Atomic Lowering.
   case X86::ATOMAND32:
     return EmitAtomicBitwiseWithCustomInserter(MI, BB, X86::AND32rr,
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index f2f19485be6..6d78d969d33 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -821,6 +821,13 @@ namespace llvm {
     MachineBasicBlock *EmitPCMP(MachineInstr *BInstr, MachineBasicBlock *BB,
                                 unsigned argNum, bool inMem) const;
 
+    /// Utility functions to emit monitor and mwait instructions. These
+    /// need to make sure that the arguments to the intrinsic are in the
+    /// correct registers.
+    MachineBasicBlock *EmitMonitor(MachineInstr *MI, MachineBasicBlock *BB)
+      const;
+    MachineBasicBlock *EmitMwait(MachineInstr *MI, MachineBasicBlock *BB) const;
+
     /// Utility function to emit atomic bitwise operations (and, or, xor).
     /// It takes the bitwise instruction to expand, the associated machine basic
     /// block, and the associated X86 opcodes for reg/reg and reg/imm.
diff --git a/lib/Target/X86/X86InstrSSE.td b/lib/Target/X86/X86InstrSSE.td
index e4e92ccbf14..0a638973b70 100644
--- a/lib/Target/X86/X86InstrSSE.td
+++ b/lib/Target/X86/X86InstrSSE.td
@@ -3640,10 +3640,21 @@ def : Pat<(v16i8 (palign:$src3 VR128:$src1, VR128:$src2)),
 //===---------------------------------------------------------------------===//
 
 // Thread synchronization
-def MONITOR : I<0x01, MRM_C8, (outs), (ins), "monitor",
-                [(int_x86_sse3_monitor EAX, ECX, EDX)]>,TB, Requires<[HasSSE3]>;
-def MWAIT   : I<0x01, MRM_C9, (outs), (ins), "mwait",
-                [(int_x86_sse3_mwait ECX, EAX)]>, TB, Requires<[HasSSE3]>;
+let usesCustomInserter = 1 in {
+def MONITOR : I<0, Pseudo, (outs), (ins i32mem:$src1, GR32:$src2, GR32:$src3),
+                "# MONITORrrr PSUEDO",
+                [(int_x86_sse3_monitor addr:$src1, GR32:$src2, GR32:$src3)]>;
+def MWAIT : I<0, Pseudo, (outs), (ins GR32:$src1, GR32:$src2),
+                "# MWAITrr PSEUDO",
+                [(int_x86_sse3_mwait GR32:$src1, GR32:$src2)]>;
+}
+
+let Uses = [EAX, ECX, EDX] in
+def MONITORrrr : I<0x01, MRM_C8, (outs), (ins), "monitor", []>, TB,
+                 Requires<[HasSSE3]>;
+let Uses = [ECX, EAX] in
+def MWAITrr   : I<0x01, MRM_C9, (outs), (ins), "mwait", []>, TB,
+                Requires<[HasSSE3]>;
 
 //===---------------------------------------------------------------------===//
 // Non-Instruction Patterns
diff --git a/test/CodeGen/X86/apm.ll b/test/CodeGen/X86/apm.ll
new file mode 100644
index 00000000000..b112185ae78
--- /dev/null
+++ b/test/CodeGen/X86/apm.ll
@@ -0,0 +1,26 @@
+; RUN: llc < %s -o - -march=x86-64 | FileCheck %s
+; PR8573
+
+; CHECK: _foo:
+; CHECK: leaq    (%rdi), %rax
+; CHECK-NEXT: movl    %esi, %ecx
+; CHECK-NEXT: monitor
+define void @foo(i8* %P, i32 %E, i32 %H) nounwind {
+entry:
+  tail call void @llvm.x86.sse3.monitor(i8* %P, i32 %E, i32 %H)
+  ret void
+}
+
+declare void @llvm.x86.sse3.monitor(i8*, i32, i32) nounwind
+
+; CHECK: _bar:
+; CHECK: movl    %edi, %ecx
+; CHECK-NEXT: movl    %esi, %eax
+; CHECK-NEXT: mwait
+define void @bar(i32 %E, i32 %H) nounwind {
+entry:
+  tail call void @llvm.x86.sse3.mwait(i32 %E, i32 %H)
+  ret void
+}
+
+declare void @llvm.x86.sse3.mwait(i32, i32) nounwind
-- 
2.34.1