Jan Hubicka <hubicka@freesoft.cz>

        * i386.c (ix86_expand_int_movcc): Convert LEU and GTU comparisons
        to LTU and GEU.  Handle more cases using sbb.

From-SVN: r29743

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b38ff43..2a61039 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Thu Sep 30 18:21:30 1999  Jan Hubicka  <hubicka@freesoft.cz>
+
+       * i386.c (ix86_expand_int_movcc): Convert LEU and GTU comparisons
+       to LTU and GEU.  Handle more cases using sbb.
+
 Thu Sep 30 18:18:39 1999  Jan Hubicka  <hubicka@freesoft.cz>
 
        * i386.md (truncatexfdf splitters): Do not use subreg.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index f654db6..34a68a7 100644 (file)
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4288,6 +4288,23 @@ ix86_expand_int_movcc (operands)
   enum rtx_code code = GET_CODE (operands[1]), compare_code;
   rtx compare_seq, compare_op;
 
+  /* When the compare code is not LTU or GEU, we can not use sbbl case.
+     In case comparsion is done with immediate, we can convert it to LTU or
+     GEU by altering the integer.  */
+
+  if ((code == LEU || code == GTU)
+      && GET_CODE (ix86_compare_op1) == CONST_INT
+      && GET_MODE (operands[0]) != HImode
+      && (unsigned int)INTVAL (ix86_compare_op1) != 0xffffffff
+      && GET_CODE (operands[2]) == CONST_INT 
+      && GET_CODE (operands[3]) == CONST_INT)
+    {
+      if (code == LEU)
+       code = LTU;
+      else
+       code = GEU;
+      ix86_compare_op1 = GEN_INT (INTVAL (ix86_compare_op1) + 1);
+    }
   start_sequence ();
   compare_op = ix86_expand_compare (code, code == EQ || code == NE);
   compare_seq = gen_sequence ();
@@ -4307,27 +4324,23 @@ ix86_expand_int_movcc (operands)
       HOST_WIDE_INT cf = INTVAL (operands[3]);
       HOST_WIDE_INT diff;
 
-      /* Special cases: */
-      if (ct == 0)
+      if (compare_code == LTU || compare_code == GEU)
        {
-         ct = cf;
-         cf = 0;
-         compare_code = reverse_condition (compare_code);
-         code = reverse_condition (code);
-       }
-      if (cf == 0 && ct == -1 && (compare_code == LTU || compare_code == GEU))
-       {
-         /*
-          * xorl dest,dest
-          * cmpl op0,op1
-          * sbbl dest,dest
-          *
-          * Size 6.
-          */
 
          /* Detect overlap between destination and compare sources.  */
          rtx tmp = out;
 
+         /* To simplify rest of code, restrict to the GEU case. */
+         if (compare_code == LTU)
+           {
+             int tmp = ct;
+             ct = cf;
+             cf = tmp;
+             compare_code = reverse_condition (compare_code);
+             code = reverse_condition (code);
+           }
+         diff = ct - cf;
+
          if (reg_overlap_mentioned_p (out, ix86_compare_op0)
              || reg_overlap_mentioned_p (out, ix86_compare_op0))
            tmp = gen_reg_rtx (SImode);
@@ -4335,8 +4348,57 @@ ix86_expand_int_movcc (operands)
          emit_insn (compare_seq);
          emit_insn (gen_x86_movsicc_0_m1 (tmp));
 
-         if (compare_code == GEU)
-           emit_insn (gen_one_cmplsi2 (tmp, tmp));
+         if (diff == 1)
+           {
+             /*
+              * cmpl op0,op1
+              * sbbl dest,dest
+              * [addl dest, ct]
+              *
+              * Size 5 - 8.
+              */
+             if (ct)
+               emit_insn (gen_addsi3 (out, out, GEN_INT (ct)));
+           }
+         else if (cf == -1)
+           {
+             /*
+              * cmpl op0,op1
+              * sbbl dest,dest
+              * orl $ct, dest
+              *
+              * Size 8.
+              */
+             emit_insn (gen_iorsi3 (out, out, GEN_INT (ct)));
+           }
+         else if (diff == -1 && ct)
+           {
+             /*
+              * cmpl op0,op1
+              * sbbl dest,dest
+              * xorl $-1, dest
+              * [addl dest, cf]
+              *
+              * Size 8 - 11.
+              */
+             emit_insn (gen_one_cmplsi2 (tmp, tmp));
+             if (cf)
+               emit_insn (gen_addsi3 (out, out, GEN_INT (cf)));
+           }
+         else
+           {
+             /*
+              * cmpl op0,op1
+              * sbbl dest,dest
+              * andl cf - ct, dest
+              * [addl dest, ct]
+              *
+              * Size 8 - 11.
+              */
+             emit_insn (gen_andsi3 (out, out, GEN_INT (cf - ct)));
+             if (ct)
+               emit_insn (gen_addsi3 (out, out, GEN_INT (ct)));
+           }
 
          if (tmp != out)
            emit_move_insn (out, tmp);