From 7cad6949e7dfdabbfd1af049b1cec2426bc5dc0d Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Sun, 4 Dec 2016 20:52:06 +0000
Subject: [PATCH] IR: Implement new pseudo-operation GetGEFromOp

---
 src/backend_x64/emit_x64.cpp         |  4 ++++
 src/frontend/ir/microinstruction.cpp | 15 +++++++++++++++
 src/frontend/ir/microinstruction.h   |  7 ++++++-
 src/frontend/ir/opcodes.inc          |  1 +
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/backend_x64/emit_x64.cpp b/src/backend_x64/emit_x64.cpp
index 83ab114e..5b9c8b7a 100644
--- a/src/backend_x64/emit_x64.cpp
+++ b/src/backend_x64/emit_x64.cpp
@@ -443,6 +443,10 @@ void EmitX64::EmitGetOverflowFromOp(IR::Block&, IR::Inst*) {
     ASSERT_MSG(false, "should never happen");
 }
 
+void EmitX64::EmitGetGEFromOp(IR::Block&, IR::Inst*) {
+    ASSERT_MSG(false, "should never happen");
+}
+
 void EmitX64::EmitPack2x32To1x64(IR::Block&, IR::Inst* inst) {
     OpArg lo;
     Xbyak::Reg64 result;
diff --git a/src/frontend/ir/microinstruction.cpp b/src/frontend/ir/microinstruction.cpp
index 95ea1260..25cc83e1 100644
--- a/src/frontend/ir/microinstruction.cpp
+++ b/src/frontend/ir/microinstruction.cpp
@@ -232,9 +232,14 @@ Inst* Inst::GetAssociatedPseudoOperation(Opcode opcode) {
     // This is faster than doing a search through the block.
     switch (opcode) {
     case IR::Opcode::GetCarryFromOp:
+        DEBUG_ASSERT(!carry_inst || carry_inst->GetOpcode() == Opcode::GetCarryFromOp);
         return carry_inst;
     case IR::Opcode::GetOverflowFromOp:
+        DEBUG_ASSERT(!overflow_inst || overflow_inst->GetOpcode() == Opcode::GetOverflowFromOp);
         return overflow_inst;
+    case IR::Opcode::GetGEFromOp:
+        DEBUG_ASSERT(!ge_inst || ge_inst->GetOpcode() == Opcode::GetGEFromOp);
+        return ge_inst;
     default:
         break;
     }
@@ -302,6 +307,10 @@ void Inst::Use(Value& value) {
         ASSERT_MSG(!value.GetInst()->overflow_inst, "Only one of each type of pseudo-op allowed");
         value.GetInst()->overflow_inst = this;
         break;
+    case Opcode::GetGEFromOp:
+        ASSERT_MSG(!value.GetInst()->ge_inst, "Only one of each type of pseudo-op allowed");
+        value.GetInst()->ge_inst = this;
+        break;
     default:
         break;
     }
@@ -312,11 +321,17 @@ void Inst::UndoUse(Value& value) {
 
     switch (op){
     case Opcode::GetCarryFromOp:
+        DEBUG_ASSERT(value.GetInst()->carry_inst->GetOpcode() == Opcode::GetCarryFromOp);
         value.GetInst()->carry_inst = nullptr;
         break;
     case Opcode::GetOverflowFromOp:
+        DEBUG_ASSERT(value.GetInst()->overflow_inst->GetOpcode() == Opcode::GetOverflowFromOp);
         value.GetInst()->overflow_inst = nullptr;
         break;
+    case Opcode::GetGEFromOp:
+        DEBUG_ASSERT(value.GetInst()->ge_inst->GetOpcode() == Opcode::GetGEFromOp);
+        value.GetInst()->ge_inst = nullptr;
+        break;
     default:
         break;
     }
diff --git a/src/frontend/ir/microinstruction.h b/src/frontend/ir/microinstruction.h
index c9634a20..1f569a6a 100644
--- a/src/frontend/ir/microinstruction.h
+++ b/src/frontend/ir/microinstruction.h
@@ -102,7 +102,12 @@ private:
     size_t use_count = 0;
     std::array<Value, 3> args;
 
-    Inst* carry_inst = nullptr;
+    // Pointers to related pseudooperations:
+    // Since not all combinations are possible, we use a union to save space
+    union {
+        Inst* carry_inst = nullptr;
+        Inst* ge_inst;
+    };
     Inst* overflow_inst = nullptr;
 };
 
diff --git a/src/frontend/ir/opcodes.inc b/src/frontend/ir/opcodes.inc
index 1d0eace1..4d742aa4 100644
--- a/src/frontend/ir/opcodes.inc
+++ b/src/frontend/ir/opcodes.inc
@@ -36,6 +36,7 @@ OPCODE(PushRSB,                 T::Void,        T::U64
 // Pseudo-operation, handled specially at final emit
 OPCODE(GetCarryFromOp,          T::U1,          T::U32                                          )
 OPCODE(GetOverflowFromOp,       T::U1,          T::U32                                          )
+OPCODE(GetGEFromOp,             T::U32,         T::U32                                          )
 
 // Calculations
 OPCODE(Pack2x32To1x64,          T::U64,         T::U32,         T::U32                          )