Merge branch 'master' into dispatch-202406

OVERVIEW.txt

@@ -94,8 +94,6 @@ sources
     jam                 - Jam script interpreter.
     parser-run-time     - Support for parsers.
     source-records      - Reads source files and tracks location.
-    stack-walker        - Debugging on UNIX by walking the stack. Nowadays
-                          directly in the run-time.
     walker              - Build has-a tree.
   project-manager       - Takes care about dependencies of projects and actual
                           invocation of linker, etc.

documentation/source/release-notes/2024.2.rst

@@ -26,6 +26,19 @@ Compiler
 * The build rules for unified executables now properly depend on
   copying included run-time libraries such as libunwind.
 
+* Optimizations that allow the type of ``if`` expressions to be more
+  accurately estimated have been improved. For example, in this
+  function:
+
+  .. code-block::
+
+    define function if-example (arg :: false-or(<integer>)) => (result :: <integer>);
+      min(arg | 20, 30)
+    end;
+
+  the comparison can now be properly inlined because the first
+  argument to :drm:`min` is known to be an :drm:`<integer>`.
+
 Tools
 =====
 
@@ -61,6 +74,11 @@ System
   :const:`$machine-architecture`.  The old name will remain, for backward
   compatibility.
 
+Other
+-----
+
+* The obsolete (32-bit x86-only) ``stack-walker`` library was removed.
+
 Contributors
 ============
 

sources/dfmc/optimization/assignment.dylan

@@ -190,14 +190,20 @@ define method maybe-rename-temporaries-in-conditional
           (c.environment, <constrain-type>,
            value: to-be-renamed, type: constraint);
       let then-f = c.consequent;
+      let merge-c :: <if-merge> = c.next-computation;
       let changed? = #f;
       rename-temporary!(to-be-renamed, tt-t);
-      for-computations(tc from then-f before c.next-computation)
+      for-computations(tc from then-f before merge-c)
         let now-changed? = rename-temporary-references!(tc, to-be-renamed, tt-t);
         changed? := (changed? | now-changed?);
       end;
+      // The left side of the merge is also part of the consequent
+      if (merge-c.merge-left-value == to-be-renamed)
+        merge-replace-left-value!(merge-c, to-be-renamed, tt-t);
+        changed? := #t;
+      end;
       if (changed?)
-        insert-computation-before!(then-f, tt-c);
+        insert-computation-before-reference!(then-f, tt-c, tt-t);
       else // It's not used in the consequent, so get rid of it.
         remove-user!(to-be-renamed, tt-c);
       end;

sources/dfmc/optimization/calls.dylan

@@ -79,13 +79,19 @@ define method do-optimize-instance?-user(c :: <if>, object, type) => ();
     = make-with-temporary(c.environment, <constrain-type>,
                           value: object, type: type);
   let then-f = c.consequent;
+  let merge-c :: <if-merge> = c.next-computation;
   let changed? = #f;
-  for-computations(tc from then-f before c.next-computation)
+  for-computations(tc from then-f before merge-c)
     let now-changed? = rename-temporary-references!(tc, object, tt-t);
     changed? := (changed? | now-changed?);
   end;
+  // The left side of the merge is also part of the consequent
+  if (merge-c.merge-left-value == object)
+    merge-replace-left-value!(merge-c, object, tt-t);
+    changed? := #t;
+  end;
   if (changed?)
-    insert-computation-before!(then-f, tt-c);
+    insert-computation-before-reference!(then-f, tt-c, tt-t);
   else // It's not used in the consequent, so get rid of it.
     remove-user!(object, tt-c);
   end

sources/environment/dswank/library.dylan

@@ -19,7 +19,6 @@ define library dswank
   use file-source-records;
   use system;
   use registry-projects;
-  //use stack-walker;
   use release-info;
   use dfmc-back-end-implementations;
 end library;
@@ -46,7 +45,6 @@ define module dswank
   use file-system;
   use locators;
   use registry-projects;
-  //use stack-walker;
   use release-info;
   use operating-system;
 end module;