From 3fa77a4f627e5ce993c88be7849e27b64e7ae80a Mon Sep 17 00:00:00 2001
From: florian <florian@freepascal.org>
Date: Mon, 24 Oct 2022 22:10:34 +0200
Subject: [PATCH]   * fix life information propagation for while loops,
 resolves #39971   * warnings/errors fixed which are caused by the new life
 information propagation   + test

---
 compiler/dbgdwarf.pas        |  3 ++-
 compiler/ngtcon.pas          |  2 +-
 compiler/optdfa.pas          |  7 ++++++-
 compiler/pgenutil.pas        |  1 +
 compiler/systems/t_bsd.pas   |  1 +
 compiler/systems/t_linux.pas |  3 ++-
 compiler/systems/t_win.pas   |  1 +
 tests/test/opt/tdfa2.pp      |  1 +
 tests/webtbs/tw39971.pp      | 19 +++++++++++++++++++
 9 files changed, 34 insertions(+), 4 deletions(-)
 create mode 100644 tests/webtbs/tw39971.pp

diff --git a/compiler/dbgdwarf.pas b/compiler/dbgdwarf.pas
index 541dfa0baf..4ddf5ad5d1 100644
--- a/compiler/dbgdwarf.pas
+++ b/compiler/dbgdwarf.pas
@@ -3486,7 +3486,8 @@ implementation
         prevline := 1;
         prevfileidx := 1;
         prevlabel := nil;
-        nolineinfolevel:=0;
+        nolineinfolevel := 0;
+        hpend := nil;
         while assigned(hp) do
           begin
             case hp.typ of
diff --git a/compiler/ngtcon.pas b/compiler/ngtcon.pas
index 18edb80953..33de135b44 100644
--- a/compiler/ngtcon.pas
+++ b/compiler/ngtcon.pas
@@ -1675,13 +1675,13 @@ function get_next_varsym(def: tabstractrecorddef; const SymList:TFPHashObjectLis
         srsym:=get_next_varsym(def,symlist,symidx);
         recsym := nil;
         startoffset:=curoffset;
+        error := false;
         while token<>_RKLAMMER do
           begin
             s:=pattern;
             sorg:=orgpattern;
             consume(_ID);
             consume(_COLON);
-            error := false;
             recsym := tsym(def.symtable.Find(s));
             if not assigned(recsym) then
               begin
diff --git a/compiler/optdfa.pas b/compiler/optdfa.pas
index ecfaa9cc8d..9c0b865cb3 100644
--- a/compiler/optdfa.pas
+++ b/compiler/optdfa.pas
@@ -289,7 +289,12 @@ unit optdfa;
                 { for while loops, node use set is included at the beginning of loop }
                 l:=twhilerepeatnode(node).right.optinfo^.life;
                 if lnf_testatbegin in twhilerepeatnode(node).loopflags then
-                  DFASetIncludeSet(l,node.optinfo^.use);
+                  begin
+                    DFASetIncludeSet(l,node.optinfo^.use);
+                    { ... loop body could be skipped, so include life info of the successsor node }
+                    if assigned(node.successor) then
+                      DFASetIncludeSet(l,node.successor.optinfo^.life);
+                  end;
 
                 UpdateLifeInfo(node,l);
 
diff --git a/compiler/pgenutil.pas b/compiler/pgenutil.pas
index eca7f6f751..c33c8da72b 100644
--- a/compiler/pgenutil.pas
+++ b/compiler/pgenutil.pas
@@ -505,6 +505,7 @@ uses
                             for j:=0 to formalobjdef.implementedinterfaces.count-1 do
                               begin
                                 objdef:=paraobjdef;
+                                intffound:=false;
                                 while assigned(objdef) do
                                   begin
                                     intffound:=assigned(
diff --git a/compiler/systems/t_bsd.pas b/compiler/systems/t_bsd.pas
index b3be7933d0..18eefbd29a 100644
--- a/compiler/systems/t_bsd.pas
+++ b/compiler/systems/t_bsd.pas
@@ -69,6 +69,7 @@ function ModulesLinkToLibc:boolean;
 var
   hp: tmodule;
 begin
+  result:=false;
   { This is called very early, ImportLibraryList is not yet merged into linkothersharedlibs.
     The former contains library names qualified with prefix and suffix (coming from
     "external 'c' name 'foo' declarations), the latter contains raw names (from "$linklib c"
diff --git a/compiler/systems/t_linux.pas b/compiler/systems/t_linux.pas
index 9768d756ac..583f714375 100644
--- a/compiler/systems/t_linux.pas
+++ b/compiler/systems/t_linux.pas
@@ -334,11 +334,12 @@ function ModulesLinkToLibc:boolean;
 var
   hp: tmodule;
 begin
+  result:=false;
   { This is called very early, ImportLibraryList is not yet merged into linkothersharedlibs.
     The former contains library names qualified with prefix and suffix (coming from
     "external 'c' name 'foo' declarations), the latter contains raw names (from "$linklib c"
     directives). }
-  hp:=tmodule(loaded_units.first);
+  hp:=tmodule(loaded_units.first);  
   while assigned(hp) do
     begin
       result:=Assigned(hp.ImportLibraryList.find(target_info.sharedClibprefix+'c'+target_info.sharedClibext));
diff --git a/compiler/systems/t_win.pas b/compiler/systems/t_win.pas
index 05e50d1c94..63855f123c 100644
--- a/compiler/systems/t_win.pas
+++ b/compiler/systems/t_win.pas
@@ -136,6 +136,7 @@ implementation
     begin
       if target_info.system=system_i386_win32 then
         begin
+          linkcygwin := false;
           hp:=tmodule(loaded_units.first);
           while assigned(hp) do
            begin
diff --git a/tests/test/opt/tdfa2.pp b/tests/test/opt/tdfa2.pp
index 67c1a60ef5..d39096fdbc 100644
--- a/tests/test/opt/tdfa2.pp
+++ b/tests/test/opt/tdfa2.pp
@@ -37,6 +37,7 @@ var
   c1: Word;
 begin
   counter:=0;  
+  c1 := 0;
   while counter<len do
   begin
     c1 := ord(s1[counter]);
diff --git a/tests/webtbs/tw39971.pp b/tests/webtbs/tw39971.pp
new file mode 100644
index 0000000000..b64e9c87cb
--- /dev/null
+++ b/tests/webtbs/tw39971.pp
@@ -0,0 +1,19 @@
+{ %opt=-O4 -Oodeadstore -S2 }
+function FileSizeFractionalPart(sz: uint64): uint32;
+var
+	fr: uint32;
+begin
+	fr := 0;
+	while sz > 1000 do
+	begin
+		fr := sz mod 1024;
+		sz := sz div 1024;
+	end;
+	result := fr;
+end;
+
+begin
+	writeln(FileSizeFractionalPart(12));
+    if FileSizeFractionalPart(12)<>0 then
+      halt(1);
+end.