From c03f19fa500c991ec8587e82390fef3144749af8 Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Sun, 14 Oct 2007 20:22:23 +0000
Subject: [PATCH]   * in case of "movzbl %dl,%edx" etc, %edx depends on its
 previous value.     regloadedwithnewvalue() gave the wrong answer for this in
 case     candependonprevvalue was false (caused a wrong optimization in the  
   space() function of the rtl)

git-svn-id: trunk@8808 -
---
 .gitattributes             |  1 +
 compiler/i386/daopt386.pas | 11 +++++++----
 tests/test/opt/tspace.pp   | 20 ++++++++++++++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 tests/test/opt/tspace.pp

diff --git a/.gitattributes b/.gitattributes
index 507005959d..3e641ad76b 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -6839,6 +6839,7 @@ tests/test/opt/treg2.pp svneol=native#text/plain
 tests/test/opt/treg3.pp svneol=native#text/plain
 tests/test/opt/treg4.pp svneol=native#text/plain
 tests/test/opt/tretopt.pp svneol=native#text/plain
+tests/test/opt/tspace.pp svneol=native#text/plain
 tests/test/t4cc1.pp svneol=native#text/plain
 tests/test/t4cc2.pp svneol=native#text/plain
 tests/test/tabstrcl.pp svneol=native#text/plain
diff --git a/compiler/i386/daopt386.pas b/compiler/i386/daopt386.pas
index dad98ba402..f6bfd944e5 100644
--- a/compiler/i386/daopt386.pas
+++ b/compiler/i386/daopt386.pas
@@ -1124,10 +1124,13 @@ begin
      (p.oper[1]^.typ = top_reg) and
      (getsupreg(p.oper[1]^.reg) = supreg) and
      (canDependOnPrevValue or
-      (p.oper[0]^.typ <> top_ref) or
-      not regInRef(supreg,p.oper[0]^.ref^)) or
-     ((p.opcode = A_POP) and
-      (getsupreg(p.oper[0]^.reg) = supreg)));
+      (p.oper[0]^.typ = top_const) or
+      ((p.oper[0]^.typ = top_reg) and
+       (getsupreg(p.oper[0]^.reg) <> supreg)) or
+      ((p.oper[0]^.typ = top_ref) and
+       not regInRef(supreg,p.oper[0]^.ref^)))) or
+    ((p.opcode = A_POP) and
+     (getsupreg(p.oper[0]^.reg) = supreg));
 end;
 
 procedure UpdateUsedRegs(var UsedRegs: TRegSet; p: tai);
diff --git a/tests/test/opt/tspace.pp b/tests/test/opt/tspace.pp
new file mode 100644
index 0000000000..713dcf7214
--- /dev/null
+++ b/tests/test/opt/tspace.pp
@@ -0,0 +1,20 @@
+{ %opt=-O2 }
+
+function space (b : byte): shortstring;
+begin
+  space[0] := chr(b);
+  FillChar (Space[1],b,' ');
+end;
+
+var
+  s: string;
+  i: longint;
+begin
+  fillchar(s,sizeof(s),255);
+  s:=space(255);
+  if length(s)<>255 then
+    halt(1);
+  for i:=1 to 255 do
+    if s[i]<>' ' then
+      halt(2);
+end.