Recent changes to Code optimization

Code optimization modified by Brandon Barker

Brandon Barker — Sun, 28 Apr 2013 13:33:32 -0000

--- v7
+++ v8
@@ -6,8 +6,10 @@

  - Making use of the knowledge that separate val declarations within the same scope technically denote different vals on the stack should not preclude one from using a natural style. For instance:

+~~~~~~~~~~~~~~~
     val x = 5
     val x = 7
+~~~~~~~~~~~~~~~

 here no extra space is allocated for the second 'x' due to constant propagation. It is in generally unlikely that such a coding style would incur any penalty.

Code optimization modified by Brandon Barker

Brandon Barker — Sun, 28 Apr 2013 13:32:32 -0000

--- v6
+++ v7
@@ -3,6 +3,13 @@
 - A `macdef` in ATS cannot involve types (but it can in ATS2); use macros only in cases where using functions would be inconvenient. [Using macros probably does not make your code run more quickly][1], since `gcc -O2` already inlines functions somewhat aggressively.

   [1]: https://groups.google.com/d/msg/ats-lang-users/Ql64LA9Wi88/fwrR7kJ3Ww0J
+
+ - Making use of the knowledge that separate val declarations within the same scope technically denote different vals on the stack should not preclude one from using a natural style. For instance:
+
+    val x = 5
+    val x = 7
+
+here no extra space is allocated for the second 'x' due to constant propagation. It is in generally unlikely that such a coding style would incur any penalty.

 ## Optimization tips ##

Code optimization modified by Brandon Barker

Brandon Barker — Sun, 28 Apr 2013 05:18:01 -0000

--- v5
+++ v6
@@ -6,7 +6,7 @@

 ## Optimization tips ##

-  - Instead of freeing an instance of a linear type and immediately creating and returning a new one with the same value in a case expression, like this
+- Instead of freeing an instance of a linear type and immediately creating and returning a new one with the same value in a case expression, like this

         case+ x of
         | ~GRgenes (genes) => GRgenes (genes)
@@ -17,3 +17,9 @@
         | GRgenes _ => (fold@ x; x)

     because `@fold` is compiled into a "noop".
+
+
+
+- Remove anonymous closure definitions from function calls when possible, to avoid having them created each time the loop is called. For instance, a simple string comparison function can be created like so:
+
+        val cmp_str = lam(x:string,y:string):int = compare (x, y)

WikiPage Code optimization modified by jeffrey

jeffrey — Thu, 14 Mar 2013 22:39:35 -0000

--- v4
+++ v5
@@ -1,29 +1,19 @@
-When not to attempt clever code optimization. 
-----------------------------------------------
+## When not to attempt clever code optimization ##

-**macdef**
-A macdef in ATS cannot involve types (but it can in ATS2); in ATS, use macros only in cases where using functions would be inconvenient. As gcc (with -O2) does inlining
-pretty aggressively, using macros so as to gain efficiency is rarely needed if at all ([source](https://groups.google.com/d/msg/ats-lang-users/Ql64LA9Wi88/fwrR7kJ3Ww0J)).
+- A `macdef` in ATS cannot involve types (but it can in ATS2); use macros only in cases where using functions would be inconvenient. [Using macros probably does not make your code run more quickly][1], since `gcc -O2` already inlines functions somewhat aggressively.

+  [1]: https://groups.google.com/d/msg/ats-lang-users/Ql64LA9Wi88/fwrR7kJ3Ww0J

+## Optimization tips ##

+  - Instead of freeing an instance of a linear type and immediately creating and returning a new one with the same value in a case expression, like this

-Optimization Tips.
-----------------------------------------------
+        case+ x of
+        | ~GRgenes (genes) => GRgenes (genes)

-**Returning a matched linear value in a case expression**
+    do this

-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-case+ x of
-| ~GRgenes (genes) => GRgenes (genes)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+        case+ x of
+        | GRgenes _ => (fold@ x; x)

-
-This means that you free a node and then create another node that is just the same as the one freed.
-
-A more efficient way to do this would be:
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-case+ x of
-| GRgenes _ => (fold@ x; x) // fold@ is compiled into a no-op.
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    because `@fold` is compiled into a "noop".

WikiPage Code Optimization modified by Brandon Barker

Brandon Barker — Thu, 14 Mar 2013 02:55:11 -0000

--- v3
+++ v4
@@ -8,7 +8,7 @@

-Optimization Tips
+Optimization Tips.
 ----------------------------------------------

 **Returning a matched linear value in a case expression**

WikiPage Code Optimization modified by Brandon Barker

Brandon Barker — Thu, 14 Mar 2013 02:52:11 -0000

--- v2
+++ v3
@@ -1,3 +1,29 @@
-**When not to attempt clever code optimization. **
+When not to attempt clever code optimization. 
+----------------------------------------------
+
+**macdef**
 A macdef in ATS cannot involve types (but it can in ATS2); in ATS, use macros only in cases where using functions would be inconvenient. As gcc (with -O2) does inlining
 pretty aggressively, using macros so as to gain efficiency is rarely needed if at all ([source](https://groups.google.com/d/msg/ats-lang-users/Ql64LA9Wi88/fwrR7kJ3Ww0J)).
+
+
+
+
+Optimization Tips
+----------------------------------------------
+
+**Returning a matched linear value in a case expression**
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+case+ x of
+| ~GRgenes (genes) => GRgenes (genes)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+This means that you free a node and then create another node that is just the same as the one freed.
+
+A more efficient way to do this would be:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+case+ x of
+| GRgenes _ => (fold@ x; x) // fold@ is compiled into a no-op.
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WikiPage Code Optimization modified by Brandon Barker

Brandon Barker — Wed, 13 Mar 2013 21:41:16 -0000

--- v1
+++ v2
@@ -1,4 +1,3 @@
-
 **When not to attempt clever code optimization. **
 A macdef in ATS cannot involve types (but it can in ATS2); in ATS, use macros only in cases where using functions would be inconvenient. As gcc (with -O2) does inlining
-pretty aggressively, using macros so as to gain efficiency is rarely needed if at all.
+pretty aggressively, using macros so as to gain efficiency is rarely needed if at all ([source](https://groups.google.com/d/msg/ats-lang-users/Ql64LA9Wi88/fwrR7kJ3Ww0J)).

WikiPage Code Optimization modified by Brandon Barker

Brandon Barker — Wed, 13 Mar 2013 21:35:10 -0000

When not to attempt clever code optimization.
A macdef in ATS cannot involve types (but it can in ATS2); in ATS, use macros only in cases where using functions would be inconvenient. As gcc (with -O2) does inlining
pretty aggressively, using macros so as to gain efficiency is rarely needed if at all.