* fixed ppc jump table generation in case a jump table has cases for the

lowest and highest element of the type of the case expression, and the
    lowest element <> 0 (mantis #29906)

git-svn-id: trunk@33630 -

.gitattributes

@@ -15041,6 +15041,7 @@ tests/webtbs/tw2983.pp svneol=native#text/plain
 tests/webtbs/tw2984.pp svneol=native#text/plain
 tests/webtbs/tw29891.pp svneol=native#text/plain
 tests/webtbs/tw29893.pp svneol=native#text/pascal
+tests/webtbs/tw29906.pp svneol=native#text/plain
 tests/webtbs/tw29912.pp svneol=native#text/plain
 tests/webtbs/tw29923.pp svneol=native#text/plain
 tests/webtbs/tw29930.pp svneol=native#text/plain

compiler/ppcgen/ngppcset.pas

@@ -75,7 +75,6 @@ implementation
         last : TConstExprInt;
         indexreg : tregister;
         href : treference;
-        mulfactor: longint;
 
         procedure genitem(list:TAsmList;t : pcaselabel);
           var
@@ -108,30 +107,28 @@ implementation
         indexreg:= cg.makeregsize(current_asmdata.CurrAsmList, hregister, OS_INT);
         { indexreg := hregister; }
         cg.a_load_reg_reg(current_asmdata.CurrAsmList, def_cgsize(opsize), OS_INT, hregister, indexreg);
+        { a <= x <= b <-> unsigned(x-a) <= (b-a) }
+        cg.a_op_const_reg(current_asmdata.CurrAsmList,OP_SUB,OS_INT,aint(min_),indexreg);
         if not(jumptable_no_range) then
           begin
-             { use aword(value-min)<aword(max-min) instead of two comparisons }
+             { case expr greater than max_ => goto elselabel }
-             { case expr outside min_ .. max_ => goto elselabel               }
-             cg.a_op_const_reg(current_asmdata.CurrAsmList,OP_SUB,OS_INT,aint(min_),indexreg);
-             { this trick requires an unsigned comparison in all cases }
              cg.a_cmp_const_reg_label(current_asmdata.CurrAsmList,OS_INT,OC_A,aint(max_)-aint(min_),indexreg,elselabel);
-             { already taken into account now }
-             min_:=0;
           end;
         current_asmdata.getjumplabel(table);
         { create reference, indexreg := indexreg * sizeof(jtentry) (= 4) }
-        mulfactor:=4;
+        cg.a_op_const_reg(current_asmdata.CurrAsmList, OP_MUL, OS_INT, 4, indexreg);
-        cg.a_op_const_reg(current_asmdata.CurrAsmList, OP_MUL, OS_INT, mulfactor, indexreg);
+        reference_reset_symbol(href, table, 0, 4);
-        reference_reset_symbol(href, table, (-aint(min_)) * mulfactor, 4);
 
         hregister:=cg.getaddressregister(current_asmdata.CurrAsmList);
         cg.a_loadaddr_ref_reg(current_asmdata.CurrAsmList,href,hregister);
         reference_reset_base(href,hregister,0,4);
         href.index:=indexreg;
         indexreg:=cg.getaddressregister(current_asmdata.CurrAsmList);
+        { load table entry }
         cg.a_load_ref_reg(current_asmdata.CurrAsmList,OS_S32,OS_ADDR,href,indexreg);
+        { add table base }
         cg.a_op_reg_reg(current_asmdata.CurrAsmList,OP_ADD,OS_ADDR,hregister,indexreg);
-
+        { jump }
         current_asmdata.CurrAsmList.concat(taicpu.op_reg(A_MTCTR, indexreg));
         current_asmdata.CurrAsmList.concat(taicpu.op_none(A_BCTR));
 

tests/webtbs/tw29906.pp

@@ -0,0 +1,70 @@
+{$mode objfpc}
+
+type
+  tsub = 1..19;
+
+function test(s: tsub): longint;
+begin
+  { use different number of instructions for several cases so wrongly
+    calculated jump table offsets are more likely to wreak havoc }
+  case s of
+    1:
+     result:=1;
+    2:
+      begin
+        writeln('two');
+        result:=2;
+      end;
+    3:
+      begin
+        s:=4;
+        result:=3;
+      end;
+    4:
+      begin
+        result:=4;
+        s:=s*s+result;
+      end;
+    5:
+      result:=5;
+    6:
+      result:=6;
+    7:
+      begin
+        s:=s+s*s div s;
+        result:=7;
+      end;
+    8:
+      result:=8;
+    9:
+      result:=9;
+    10:
+      result:=10;
+    11:
+      result:=11;
+    12:
+      result:=12;
+    13:
+      result:=13;
+    14:
+      result:=14;
+    15:
+      result:=15;
+    16:
+      result:=16;
+    17:
+      result:=17;
+    18:
+      result:=18;
+    19:
+      result:=19;
+  end;
+end;
+
+var
+  i: tsub;
+begin
+  for i:=low(tsub) to high(tsub) do
+    if test(i)<>i then
+      halt(i);
+end.