+ extend the i8086 peephole optimization that converts certain sequences to lds

  and les instructions to also support the lss, lfs and lgs instructions on i386
  (won't be generated by the current code generator, but might become useful in
  the future, if we start using the fs and gs segment registers as well)

git-svn-id: trunk@35858 -

compiler/i8086/aoptcpu.pas

@@ -39,7 +39,9 @@ unit aoptcpu;
   Implementation
 
     uses
+      globals,
       verbose,
+      cpuinfo,
       aoptx86,
       aasmcpu;
 
@@ -70,7 +72,11 @@ unit aoptcpu;
 
                       OpsEqual(taicpu(hp1).oper[1]^,taicpu(hp2).oper[0]^) and
 
-                      (MatchOperand(taicpu(hp2).oper[1]^,NR_ES) or MatchOperand(taicpu(hp2).oper[1]^,NR_DS)) and
+                      (MatchOperand(taicpu(hp2).oper[1]^,NR_ES) or MatchOperand(taicpu(hp2).oper[1]^,NR_DS) or
+                       ((current_settings.cputype>=cpu_386) and
+                        (MatchOperand(taicpu(hp2).oper[1]^,NR_SS) or
+                         MatchOperand(taicpu(hp2).oper[1]^,NR_FS) or
+                         MatchOperand(taicpu(hp2).oper[1]^,NR_GS)))) and
 
                       (taicpu(p).oper[0]^.ref^.base=taicpu(hp1).oper[0]^.ref^.base) and
                       (taicpu(p).oper[0]^.ref^.index=taicpu(hp1).oper[0]^.ref^.index) and
@@ -85,6 +91,12 @@ unit aoptcpu;
                             taicpu(p).opcode:=A_LDS;
                           NR_ES:
                             taicpu(p).opcode:=A_LES;
+                          NR_SS:
+                            taicpu(p).opcode:=A_LSS;
+                          NR_FS:
+                            taicpu(p).opcode:=A_LFS;
+                          NR_GS:
+                            taicpu(p).opcode:=A_LGS;
                           else
                             internalerror(2015092601);
                         end;