compiler: monomorphize int64(round(x)) to not lose precision.

whitequark · whitequark · commit 68de7245545e · 2016-12-02T15:02:44.000Z
This applies to any expression with an indeterminate integer type
cast to int64(), not just round().
diff --git a/artiq/compiler/module.py b/artiq/compiler/module.py
@@ -48,6 +48,7 @@ def __init__(self, src, ref_period=1e-6, attribute_writeback=True, remarks=False
         self.globals = src.globals
 
         int_monomorphizer = transforms.IntMonomorphizer(engine=self.engine)
+        cast_monomorphizer = transforms.CastMonomorphizer(engine=self.engine)
         inferencer = transforms.Inferencer(engine=self.engine)
         monomorphism_validator = validators.MonomorphismValidator(engine=self.engine)
         escape_validator = validators.EscapeValidator(engine=self.engine)
@@ -63,6 +64,7 @@ def __init__(self, src, ref_period=1e-6, attribute_writeback=True, remarks=False
         interleaver = transforms.Interleaver(engine=self.engine)
         invariant_detection = analyses.InvariantDetection(engine=self.engine)
 
+        cast_monomorphizer.visit(src.typedtree)
         int_monomorphizer.visit(src.typedtree)
         inferencer.visit(src.typedtree)
         monomorphism_validator.visit(src.typedtree)
diff --git a/artiq/compiler/testbench/inferencer.py b/artiq/compiler/testbench/inferencer.py
@@ -1,7 +1,7 @@
 import sys, fileinput, os
 from pythonparser import source, diagnostic, algorithm, parse_buffer
 from .. import prelude, types
-from ..transforms import ASTTypedRewriter, Inferencer, IntMonomorphizer
+from ..transforms import ASTTypedRewriter, Inferencer, IntMonomorphizer, CastMonomorphizer
 from ..transforms import IODelayEstimator
 
 class Printer(algorithm.Visitor):
@@ -84,6 +84,7 @@ def process_diagnostic(diag):
     typed = ASTTypedRewriter(engine=engine, prelude=prelude.globals()).visit(parsed)
     Inferencer(engine=engine).visit(typed)
     if monomorphize:
+        CastMonomorphizer(engine=engine).visit(typed)
         IntMonomorphizer(engine=engine).visit(typed)
         Inferencer(engine=engine).visit(typed)
     if iodelay:
diff --git a/artiq/compiler/transforms/__init__.py b/artiq/compiler/transforms/__init__.py
@@ -1,6 +1,7 @@
 from .asttyped_rewriter import ASTTypedRewriter
 from .inferencer import Inferencer
 from .int_monomorphizer import IntMonomorphizer
+from .cast_monomorphizer import CastMonomorphizer
 from .iodelay_estimator import IODelayEstimator
 from .artiq_ir_generator import ARTIQIRGenerator
 from .dead_code_eliminator import DeadCodeEliminator
diff --git a/artiq/compiler/transforms/cast_monomorphizer.py b/artiq/compiler/transforms/cast_monomorphizer.py
@@ -0,0 +1,24 @@
+"""
+:class:`CastMonomorphizer` uses explicit casts to monomorphize
+expressions of undetermined integer type to either 32 or 64 bits.
+"""
+
+from pythonparser import algorithm, diagnostic
+from .. import types, builtins
+
+class CastMonomorphizer(algorithm.Visitor):
+    def __init__(self, engine):
+        self.engine = engine
+
+    def visit_CallT(self, node):
+        self.generic_visit(node)
+
+        if (types.is_builtin(node.func.type, "int") or
+                types.is_builtin(node.func.type, "int32") or
+                types.is_builtin(node.func.type, "int64")):
+            typ = node.type.find()
+            if (not types.is_var(typ["width"]) and
+                    builtins.is_int(node.args[0].type) and
+                    types.is_var(node.args[0].type.find()["width"])):
+                node.args[0].type.unify(typ)
+
diff --git a/artiq/compiler/transforms/inferencer.py b/artiq/compiler/transforms/inferencer.py
@@ -780,7 +780,6 @@ def makenotes(printer, typea, typeb, loca, locb):
         elif types.is_builtin(typ, "round"):
             valid_forms = lambda: [
                 valid_form("round(x:float) -> numpy.int?"),
-                valid_form("round(x:float, width=?) -> numpy.int?")
             ]
 
             self._unify(node.type, builtins.TInt(),
@@ -791,19 +790,6 @@ def makenotes(printer, typea, typeb, loca, locb):
 
                 self._unify(arg.type, builtins.TFloat(),
                             arg.loc, None)
-            elif len(node.args) == 1 and len(node.keywords) == 1 and \
-                    builtins.is_numeric(node.args[0].type) and \
-                    node.keywords[0].arg == 'width':
-                width = node.keywords[0].value
-                if not (isinstance(width, asttyped.NumT) and isinstance(width.n, int)):
-                    diag = diagnostic.Diagnostic("error",
-                        "the width argument of round() must be an integer literal", {},
-                        node.keywords[0].loc)
-                    self.engine.process(diag)
-                    return
-
-                self._unify(node.type, builtins.TInt(types.TValue(width.n)),
-                            node.loc, None)
             else:
                 diagnose(valid_forms())
         elif types.is_builtin(typ, "min") or types.is_builtin(typ, "max"):
diff --git a/artiq/test/lit/inferencer/builtin_calls.py b/artiq/test/lit/inferencer/builtin_calls.py
@@ -30,6 +30,3 @@
 
 # CHECK-L: round:<function round>(1.0:float):numpy.int?
 round(1.0)
-
-# CHECK-L: round:<function round>(1.0:float, width=64:numpy.int?):numpy.int64
-round(1.0, width=64)
diff --git a/artiq/test/lit/monomorphism/integers.py b/artiq/test/lit/monomorphism/integers.py
@@ -6,6 +6,3 @@
 
 y = int(1)
 # CHECK-L: y: numpy.int32
-
-z = round(1.0)
-# CHECK-L: z: numpy.int32
diff --git a/artiq/test/lit/monomorphism/round.py b/artiq/test/lit/monomorphism/round.py
@@ -0,0 +1,11 @@
+# RUN: %python -m artiq.compiler.testbench.inferencer +mono %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+
+# CHECK-L: round:<function round>(1.0:float):numpy.int32
+round(1.0)
+
+# CHECK-L: round:<function round>(2.0:float):numpy.int32
+int32(round(2.0))
+
+# CHECK-L: round:<function round>(3.0:float):numpy.int64
+int64(round(3.0))
