i960.c (i960_function_arg_advance): Ensure all regs marked as used if stack is also...

	* i960/i960.c (i960_function_arg_advance): Ensure all regs marked
	as used if stack is also used (for va_start).
	(i960_setup_incoming_varargs): Rewrite to be similar to Intel's
	version, but don't allocate reg block unless necessary.

From-SVN: r9226

diff --git a/gcc/config/i960/i960.c b/gcc/config/i960/i960.c
index 7d72000b3c8a6466d34cabd07b20def715abb90b..18175b72e2c4c3f9062d6059c42c55595dc31b9f 100644 (file)
--- a/gcc/config/i960/i960.c
+++ b/gcc/config/i960/i960.c
@@ -1,5 +1,5 @@
 /* Subroutines used for code generation on intel 80960.
-   Copyright (C) 1992 Free Software Foundation, Inc.
+   Copyright (C) 1992, 1995 Free Software Foundation, Inc.
    Contributed by Steven McGeady, Intel Corp.
    Additional Work by Glenn Colon-Bonet, Jonathan Shapiro, Andy Wilson
    Converted to GCC 2.0 by Jim Wilson and Michael Tiemann, Cygnus Support.
@@ -2069,7 +2069,12 @@ i960_function_arg_advance (cum, mode, type, named)
   if (size > 4 || cum->ca_nstackparms != 0
       || (size + ROUND_PARM (cum->ca_nregparms, align)) > NPARM_REGS
       || MUST_PASS_IN_STACK (mode, type))
-    cum->ca_nstackparms = ROUND_PARM (cum->ca_nstackparms, align) + size;
+    {
+      /* Indicate that all the registers are in use, even if all are not,
+        so va_start will compute the right value.  */
+      cum->ca_nregparms = NPARM_REGS;
+      cum->ca_nstackparms = ROUND_PARM (cum->ca_nstackparms, align) + size;
+    }
   else
     cum->ca_nregparms = ROUND_PARM (cum->ca_nregparms, align) + size;
 }
@@ -2200,44 +2205,47 @@ i960_setup_incoming_varargs (cum, mode, type, pretend_size, no_rtl)
      int *pretend_size;
      int no_rtl;
 {
-  if (cum->ca_nregparms < NPARM_REGS)
-    {
-      int first_reg_offset = cum->ca_nregparms;
+  /* Note: for a varargs fn with only a va_alist argument, this is 0.  */
+  int first_reg = cum->ca_nregparms;
 
-      if (! (no_rtl))
-       {
-         rtx label = gen_label_rtx ();
-         rtx regblock;
-
-         /* If arg_pointer_rtx == 0, no arguments were passed on the stack
-            and we need to allocate a chunk to save the registers (if any
-            arguments were passed on the stack the caller would allocate the
-            48 bytes as well).  We must allocate all 48 bytes (12*4) because
-            arg_pointer_rtx is saved at the front, the anonymous args are
-            saved at the end.  */
-         emit_insn (gen_cmpsi (arg_pointer_rtx, const0_rtx));
-         emit_jump_insn (gen_bne (label));
-         emit_insn (gen_rtx (SET, VOIDmode, arg_pointer_rtx,
-                             stack_pointer_rtx));
-         emit_insn (gen_rtx (SET, VOIDmode, stack_pointer_rtx,
-                             memory_address (SImode,
-                                             plus_constant (stack_pointer_rtx,
-                                                            48))));
-         emit_label (label);
-
-         /* Any anonymous args passed in regs?  */
-         if (first_reg_offset + 1 < NPARM_REGS)
-           {
-             rtx regblock;
-             regblock = gen_rtx (MEM, BLKmode,
-                                 plus_constant (arg_pointer_rtx,
-                                                (first_reg_offset + 1) * 4));
-             move_block_from_reg (first_reg_offset + 1, regblock,
-                                  NPARM_REGS - first_reg_offset - 1,
-                                  ((NPARM_REGS - first_reg_offset - 1)
-                                   * UNITS_PER_WORD));
-           }
-       }
+  /* Copy only unnamed register arguments to memory.  If there are
+     any stack parms, there are no unnamed arguments in registers, and
+     an argument block was already allocated by the caller.
+     Remember that any arg bigger than 4 words is passed on the stack as
+     are all subsequent args.
+
+     If there are no stack arguments but there are exactly NPARM_REGS
+     registers, either there were no extra arguments or the caller
+     allocated an argument block. */
+
+  if (cum->ca_nstackparms == 0 && first_reg < NPARM_REGS && !no_rtl)
+    {
+      rtx label = gen_label_rtx ();
+      rtx regblock;
+
+      /* If arg_pointer_rtx == 0, no arguments were passed on the stack
+        and we need to allocate a chunk to save the registers (if any
+        arguments were passed on the stack the caller would allocate the
+        48 bytes as well).  We must allocate all 48 bytes (12*4) because
+        va_start assumes it.  */
+      emit_insn (gen_cmpsi (arg_pointer_rtx, const0_rtx));
+      emit_jump_insn (gen_bne (label));
+      emit_insn (gen_rtx (SET, VOIDmode, arg_pointer_rtx,
+                         stack_pointer_rtx));
+      emit_insn (gen_rtx (SET, VOIDmode, stack_pointer_rtx,
+                         memory_address (SImode,
+                                         plus_constant (stack_pointer_rtx,
+                                                        48))));
+      emit_label (label);
+
+      /* ??? Note that we unnecessarily store one extra register for stdarg
+        fns.  We could optimize this, but it's kept as for now.  */
+      regblock = gen_rtx (MEM, BLKmode,
+                         plus_constant (arg_pointer_rtx,
+                                        first_reg * 4));
+      move_block_from_reg (first_reg, regblock,
+                          NPARM_REGS - first_reg,
+                          (NPARM_REGS - first_reg) * UNITS_PER_WORD);
     }
 }