From d10f46ec597fbaa27fd01066afd918bc2feceb18 Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Thu, 23 Dec 2010 15:24:29 +0000
Subject: [PATCH]   * skip instructions containing a reference with a segment
 prefix (fixes     mantis #18113)

git-svn-id: trunk@16619 -
---
 .gitattributes            |  1 +
 compiler/i386/popt386.pas | 34 ++++++++++++++++++++++++++++++++++
 tests/webtbs/tw18113.pp   | 22 ++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 tests/webtbs/tw18113.pp

diff --git a/.gitattributes b/.gitattributes
index cd53a96f31..00f3f0a322 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -10907,6 +10907,7 @@ tests/webtbs/tw18075.pp svneol=native#text/pascal
 tests/webtbs/tw18082.pp svneol=native#text/plain
 tests/webtbs/tw18085.pp svneol=native#text/pascal
 tests/webtbs/tw18086.pp svneol=native#text/pascal
+tests/webtbs/tw18113.pp svneol=native#text/plain
 tests/webtbs/tw18123.pp svneol=native#text/pascal
 tests/webtbs/tw18127.pp svneol=native#text/pascal
 tests/webtbs/tw18131.pp svneol=native#text/pascal
diff --git a/compiler/i386/popt386.pas b/compiler/i386/popt386.pas
index 3d5e6f1822..2952778919 100644
--- a/compiler/i386/popt386.pas
+++ b/compiler/i386/popt386.pas
@@ -128,6 +128,20 @@ begin
 end;
 
 
+{ returns true if p contains a memory operand with a segment set }
+function InsContainsSegRef(p: taicpu): boolean;
+var
+  i: longint;
+begin
+  result:=true;
+  for i:=0 to p.opercnt-1 do
+    if (p.oper[i]^.typ=top_ref) and
+       (p.oper[i]^.ref^.segment<>NR_NO) then
+      exit;
+  result:=false;
+end;
+
+
 procedure PrePeepHoleOpts(asml: TAsmList; BlockStart, BlockEnd: tai);
 var
   p,hp1: tai;
@@ -140,6 +154,11 @@ begin
       case p.Typ Of
         Ait_Instruction:
           begin
+            if InsContainsSegRef(taicpu(p)) then
+              begin
+                p := tai(p.next);
+                continue;
+              end;
             case taicpu(p).opcode Of
               A_IMUL:
                 {changes certain "imul const, %reg"'s to lea sequences}
@@ -606,6 +625,11 @@ begin
       case p.Typ Of
         ait_instruction:
           begin
+            if InsContainsSegRef(taicpu(p)) then
+              begin
+                p := tai(p.next);
+                continue;
+              end;
             { Handle Jmp Optimizations }
             if taicpu(p).is_jmp then
               begin
@@ -1779,6 +1803,11 @@ begin
       case p.Typ Of
         Ait_Instruction:
           begin
+            if InsContainsSegRef(taicpu(p)) then
+              begin
+                p := tai(p.next);
+                continue;
+              end;
             case taicpu(p).opcode Of
               A_Jcc:
                 begin
@@ -2065,6 +2094,11 @@ begin
       case p.Typ Of
         Ait_Instruction:
           begin
+            if InsContainsSegRef(taicpu(p)) then
+              begin
+                p := tai(p.next);
+                continue;
+              end;
             case taicpu(p).opcode Of
               A_CALL:
                 if (current_settings.optimizecputype < cpu_Pentium2) and
diff --git a/tests/webtbs/tw18113.pp b/tests/webtbs/tw18113.pp
new file mode 100644
index 0000000000..bb61963d07
--- /dev/null
+++ b/tests/webtbs/tw18113.pp
@@ -0,0 +1,22 @@
+{ %target=go32v2 }
+{ %interactive }
+
+{ check whether this program writes '*' }
+
+Procedure Confuse;
+begin
+
+end;
+
+
+Procedure TestBug(chr:word);
+begin
+Confuse; {if you comment it, everything is fine even in Level 2}
+Mem[$B800:0]:=byte(chr);
+end;
+
+begin
+writeln(#13#10#13#10);
+TestBug(42); {should print '*'}
+readln;
+end.