Improve alias analysis on ia64

From-SVN: r38549

gcc/ChangeLog

 2000-12-29  Bernd Schmidt  <bernds@redhat.com>
 
+	* ia64.c (ia64_expand_load_address): Accept additional scratch
+	register argument.  All callers & prototype changed.
+	Use scratch register when generating load_symptr insns.
+	* ia64.md (movdi_symbolic): Clobber a scratch register.  Use it
+	when calling ia64_expand_load_address.
+	(movdi): Generate movdi_symbolic with additional operand.
+	(load_gprel64): Use pic_offset_table_rtx instead of (reg:DI 1).
+	(load_symptr): Likewise.  Use additional operand as a scratch
+	register instead of generating it here.
+
 	* basic-block.h: Add a comment.
 	* flow.c (PROP_POSTRELOAD): New macro.
 	(update_life_info): Add it to prop_flags.

gcc/config/ia64/ia64-protos.h

@@ -81,7 +81,7 @@ extern void ia64_function_prologue PARAMS((FILE *, int));
 extern void ia64_function_epilogue PARAMS((FILE *, int));
 
 extern int ia64_direct_return PARAMS((void));
-extern void ia64_expand_load_address PARAMS((rtx, rtx));
+extern void ia64_expand_load_address PARAMS((rtx, rtx, rtx));
 extern int ia64_hard_regno_rename_ok PARAMS((int, int));
 
 extern void ia64_initialize_trampoline PARAMS((rtx, rtx, rtx));

gcc/config/ia64/ia64.c

@@ -798,8 +798,8 @@ ia64_depz_field_mask (rop, rshift)
 /* ??? Should generalize this, so that we can also support 32 bit pointers.  */
 
 void
-ia64_expand_load_address (dest, src)
-      rtx dest, src;
+ia64_expand_load_address (dest, src, scratch)
+      rtx dest, src, scratch;
 {
   rtx temp;
 
@@ -831,11 +831,22 @@ ia64_expand_load_address (dest, src)
       lo = ((ofs & 0x3fff) ^ 0x2000) - 0x2000;
       hi = ofs - lo;
 
-      emit_insn (gen_load_symptr (subtarget, plus_constant (sym, hi)));
+      if (! scratch)
+	scratch = no_new_pseudos ? subtarget : gen_reg_rtx (DImode);
+
+      emit_insn (gen_load_symptr (subtarget, plus_constant (sym, hi),
+				  scratch));
       emit_insn (gen_adddi3 (temp, subtarget, GEN_INT (lo)));
     }
   else
-    emit_insn (gen_load_symptr (temp, src));
+    {
+      rtx insn;
+      if (! scratch)
+	scratch = no_new_pseudos ? temp : gen_reg_rtx (DImode);
+
+      insn = emit_insn (gen_load_symptr (temp, src, scratch));
+      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, src, REG_NOTES (insn));
+    }
 
   if (temp != dest)
     emit_move_insn (dest, temp);

gcc/config/ia64/ia64.md

@@ -484,9 +484,9 @@
       if (rtx_equal_function_value_matters
 	  && ! (GET_CODE (operands[1]) == SYMBOL_REF
 		&& SYMBOL_REF_FLAG (operands[1])))
-	emit_insn (gen_movdi_symbolic (operands[0], operands[1]));
+	emit_insn (gen_movdi_symbolic (operands[0], operands[1], gen_reg_rtx (DImode)));
       else
-        ia64_expand_load_address (operands[0], operands[1]);
+        ia64_expand_load_address (operands[0], operands[1], NULL_RTX);
       DONE;
     }
 }")
@@ -551,12 +551,13 @@
 (define_insn_and_split "movdi_symbolic"
   [(set (match_operand:DI 0 "register_operand" "=r")
 	(match_operand:DI 1 "symbolic_operand" "s"))
+   (clobber (match_operand:DI  2 "register_operand" "+r"))
    (use (reg:DI 1))]
   ""
   "* abort ();"
   ""
   [(const_int 0)]
-  "ia64_expand_load_address (operands[0], operands[1]); DONE;")
+  "ia64_expand_load_address (operands[0], operands[1], operands[2]); DONE;")
 
 (define_insn "*movdi_internal_astep"
   [(set (match_operand:DI 0 "destination_operand"
@@ -640,7 +641,7 @@
   [(const_int 0)]
   "
 {
-  ia64_expand_load_address (operands[0], operands[1]);
+  ia64_expand_load_address (operands[0], operands[1], NULL_RTX);
   DONE;
 }")
 
@@ -679,24 +680,25 @@
 
 (define_expand "load_gprel64"
   [(set (match_dup 2)
-	(minus:DI (match_operand:DI 1 "symbolic_operand" "") (reg:DI 1)))
+	(minus:DI (match_operand:DI 1 "symbolic_operand" "") (match_dup 3)))
    (set (match_operand:DI 0 "register_operand" "")
-	(plus:DI (reg:DI 1) (match_dup 2)))]
+	(plus:DI (match_dup 3) (match_dup 2)))]
   ""
   "
 {
   operands[2] = no_new_pseudos ? operands[0] : gen_reg_rtx (DImode);
+  operands[3] = pic_offset_table_rtx;
 }")
 
 (define_expand "load_symptr"
-  [(set (match_dup 2)
-	(plus:DI (reg:DI 1) (match_operand:DI 1 "got_symbolic_operand" "")))
+  [(set (match_operand:DI 2 "register_operand" "")
+	(plus:DI (match_dup 4) (match_operand:DI 1 "got_symbolic_operand" "")))
    (set (match_operand:DI 0 "register_operand" "") (match_dup 3))]
   ""
   "
 {
-  operands[2] = no_new_pseudos ? operands[0] : gen_reg_rtx (DImode);
   operands[3] = gen_rtx_MEM (DImode, operands[2]);
+  operands[4] = pic_offset_table_rtx;
   RTX_UNCHANGING_P (operands[3]) = 1;
 }")