From 76cef042a5fdd2cb8fbbfb094bb82f70a83fd143 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Tue, 19 Aug 2014 17:52:55 +0800
Subject: [PATCH] compiler/ir: introduce Fraction type (incomplete)

---
 artiq/compiler/ir_ast_body.py |  7 +++
 artiq/compiler/ir_values.py   | 86 +++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/artiq/compiler/ir_ast_body.py b/artiq/compiler/ir_ast_body.py
index 57f3b1018..3437c1b56 100644
--- a/artiq/compiler/ir_ast_body.py
+++ b/artiq/compiler/ir_ast_body.py
@@ -107,6 +107,13 @@ class Visitor:
 		fn = node.func.id
 		if fn in ast_unfuns:
 			return ast_unfuns[fn](self.visit_expression(node.args[0]), self.builder)
+		elif fn == "Fraction":
+			r = ir_values.VFraction()
+			if self.builder is not None:
+				numerator = self.visit_expression(node.args[0])
+				denominator = self.visit_expression(node.args[1])
+				r.set_value_nd(self.builder, numerator, denominator)
+			return r
 		elif fn == "syscall":
 			return self.env.syscall(node.args[0].s,
 				[self.visit_expression(expr) for expr in node.args[1:]],
diff --git a/artiq/compiler/ir_values.py b/artiq/compiler/ir_values.py
index 156b4aac9..b5e9ed85d 100644
--- a/artiq/compiler/ir_values.py
+++ b/artiq/compiler/ir_values.py
@@ -186,6 +186,92 @@ class VBool(VInt):
 			r.set_ssa_value(builder, self.get_ssa_value(builder))
 		return r
 
+# Fraction type
+
+class VFraction(_Value):
+	def get_llvm_type(self):
+		return lc.Type.vector(lc.Type.int(64), 2)
+
+	def __repr__(self):
+		return "<VFraction>"
+
+	def same_type(self, other):
+		return isinstance(other, VFraction)
+
+	def merge(self, other):
+		if not isinstance(other, VFraction):
+			raise TypeError
+
+	def _simplify(self, builder):
+		pass # TODO
+
+	def set_value_nd(self, builder, numerator, denominator):
+		numerator = numerator.o_int64(builder).get_ssa_value(builder)
+		denominator = denominator.o_int64(builder).get_ssa_value(builder)
+		value = lc.Constant.undef(lc.Type.vector(lc.Type.int(64), 2))
+		value = builder.insert_element(value, numerator, lc.Constant.int(lc.Type.int(), 0))
+		value = builder.insert_element(value, denominator, lc.Constant.int(lc.Type.int(), 1))
+		self.set_ssa_value(builder, value)
+		self._simplify(builder)
+
+	def set_value(self, builder, n):
+		if not isinstance(n, VFraction):
+			raise TypeError
+		self.set_ssa_value(builder, n.get_ssa_value(builder))
+
+	def o_bool(self, builder):
+		r = VBool()
+		if builder is not None:
+			zero = lc.Constant.int(lc.Type.int(64), 0)
+			numerator = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), 0))
+			r.set_ssa_value(builder, builder.icmp(lc.ICMP_NE, numerator, zero))
+		return r
+
+	def o_intx(self, target_bits, builder):
+		if builder is None:
+			return VInt(target_bits)
+		else:
+			r = VInt(64)
+			numerator = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), 0))
+			denominator = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), 1))
+			r.set_ssa_value(builder, builder.sdiv(numerator, denominator))
+			return r.o_intx(target_bits, builder)
+
+	def o_roundx(self, target_bits, builder):
+		if builder is None:
+			return VInt(target_bits)
+		else:
+			r = VInt(64)
+			numerator = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), 0))
+			denominator = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), 1))
+			h_denominator = builder.ashr(denominator, lc.Constant.int(lc.Type.int(), 1))
+			r_numerator = builder.add(numerator, h_denominator)
+			r.set_ssa_value(builder, builder.sdiv(r_numerator, denominator))
+			return r.o_intx(target_bits, builder)
+
+	def _o_eq_inv(self, other, builder, invert):
+		if isinstance(other, VFraction):
+			r = VBool()
+			if builder is not None:
+				ee = []
+				for i in range(2):
+					es = builder.extract_element(self.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), i))
+					eo = builder.extract_element(other.get_ssa_value(builder), lc.Constant.int(lc.Type.int(), i))
+					ee.append(builder.icmp(lc.ICMP_EQ, es, eo))
+				ssa_r = builder.and_(ee[0], ee[1])
+				if invert:
+					ssa_r = builder.xor(ssa_r, lc.Constant.int(lc.Type.int(1), 1))
+				r.set_ssa_value(builder, ssa_r)
+			return r
+		else:
+			return NotImplemented
+
+	def o_eq(self, other, builder):
+		return self._o_eq_inv(other, builder, False)
+
+	def o_ne(self, other, builder):
+		return self._o_eq_inv(other, builder, True)
+
 # Operators
 
 def _make_unary_operator(op_name):