From a460a637ddd4e35acc468c01528ead973c50751b Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Tue, 27 Sep 2016 07:59:47 -0700
Subject: [PATCH] Add legalization patterns.

---
 meta/cretonne/legalize.py | 48 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 meta/cretonne/legalize.py

diff --git a/meta/cretonne/legalize.py b/meta/cretonne/legalize.py
new file mode 100644
index 0000000000..14eb879abd
--- /dev/null
+++ b/meta/cretonne/legalize.py
@@ -0,0 +1,48 @@
+"""
+Patterns for legalizing the `base` instruction set.
+
+The base Cretonne instruction set is 'fat', and many instructions don't have
+legal representations in a given target ISA. This module defines legalization
+patterns that describe how base instructions can be transformed to other base
+instructions that are legal.
+"""
+from __future__ import absolute_import
+from .base import iadd, iadd_cout, iadd_cin, isplit_lohi, iconcat_lohi
+from .base import isub, isub_bin, isub_bout
+from .ast import Var
+from .xform import Rtl, XFormGroup
+
+
+narrow = XFormGroup()
+
+x = Var('x')
+y = Var('y')
+a = Var('a')
+b = Var('b')
+c = Var('c')
+xl = Var('xl')
+xh = Var('xh')
+yl = Var('yl')
+yh = Var('yh')
+al = Var('al')
+ah = Var('ah')
+
+narrow.legalize(
+        a << iadd(x, y),
+        Rtl(
+            (xl, xh) << isplit_lohi(x),
+            (yl, yh) << isplit_lohi(y),
+            (al, c) << iadd_cout(xl, yl),
+            ah << iadd_cin(xh, yh, c),
+            a << iconcat_lohi(al, ah)
+        ))
+
+narrow.legalize(
+        a << isub(x, y),
+        Rtl(
+            (xl, xh) << isplit_lohi(x),
+            (yl, yh) << isplit_lohi(y),
+            (al, b) << isub_bout(xl, yl),
+            ah << isub_bin(xh, yh, b),
+            a << iconcat_lohi(al, ah)
+        ))