i386.c (ix86_save_reg): Examine regs_ever_live...

        * config/i386/i386.c (ix86_save_reg): Examine regs_ever_live,
        not current_function_uses_pic_offset_table and
        current_function_uses_const_pool; examine current_function_profile.
        (ix86_expand_prologue): Likewise.  Add pic_offset_table_rtx as
        input to blockage if needed.
        (ix86_expand_call): Do not set current_function_uses_pic_offset_table.
        (legitimize_pic_address): Likewise.  Set regs_ever_live for
        pic_offset_table_rtx when invoked during reload.
        * config/i386/i386.h (FINALIZE_PIC): Remove.
        * config/i386/i386.md (tablejump): Reformat.  Do not set
        current_function_uses_pic_offset_table.
        (tls_global_dynamic, tls_local_dynamic_base): Likewise.
        (blockage): Accept anything as operand 0.

From-SVN: r53981

4 files changed, 61 insertions, 52 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index eb3f5f0..f391122 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2002-05-28  Richard Henderson  <rth@redhat.com>
+
+	* config/i386/i386.c (ix86_save_reg): Examine regs_ever_live,
+	not current_function_uses_pic_offset_table and
+	current_function_uses_const_pool; examine current_function_profile.
+	(ix86_expand_prologue): Likewise.  Add pic_offset_table_rtx as
+	input to blockage if needed.
+	(ix86_expand_call): Do not set current_function_uses_pic_offset_table.
+	(legitimize_pic_address): Likewise.  Set regs_ever_live for
+	pic_offset_table_rtx when invoked during reload.
+	* config/i386/i386.h (FINALIZE_PIC): Remove.
+	* config/i386/i386.md (tablejump): Reformat.  Do not set
+	current_function_uses_pic_offset_table.
+	(tls_global_dynamic, tls_local_dynamic_base): Likewise.
+	(blockage): Accept anything as operand 0.
+
 2002-05-28  Jason Thorpe  <thorpej@wasabisystems.com>
 
 	* config/netbsd-aout.h (NETBSD_OS_CPP_BUILTINS_AOUT): Define
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 39831af..7e98741 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4012,8 +4012,8 @@ ix86_save_reg (regno, maybe_eh_return)
      int maybe_eh_return;
 {
   if (regno == PIC_OFFSET_TABLE_REGNUM
-      && (current_function_uses_pic_offset_table
-	  || current_function_uses_const_pool
+      && (regs_ever_live[regno]
+	  || current_function_profile
 	  || current_function_calls_eh_return))
     return 1;
 
@@ -4235,9 +4235,9 @@ void
 ix86_expand_prologue ()
 {
   rtx insn;
-  int pic_reg_used = (flag_pic && (current_function_uses_pic_offset_table
-				  || current_function_uses_const_pool)
-		      && !TARGET_64BIT);
+  int pic_reg_used = (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
+		      && (regs_ever_live[PIC_OFFSET_TABLE_REGNUM]
+			  || current_function_profile));
   struct ix86_frame frame;
   int use_mov = 0;
   HOST_WIDE_INT allocate;
@@ -4320,18 +4320,19 @@ ix86_expand_prologue ()
     {
       insn = emit_insn (gen_set_got (pic_offset_table_rtx));
 
-      /* ??? The current_function_uses_pic_offset_table flag is woefully
-	 inaccurate, as it isn't updated as code gets deleted.  Allow the
-	 thing to be removed.  A better solution would be to actually get
-	 proper liveness for ebx, as then we won't save/restore it too.  */
+      /* Even with accurate pre-reload life analysis, we can wind up
+	 deleting all references to the pic register after reload.
+	 Consider if cross-jumping unifies two sides of a branch
+	 controled by a comparison vs the only read from a global.
+	 In which case, allow the set_got to be deleted, though we're
+	 too late to do anything about the ebx save in the prologue.  */
       REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx, NULL);
     }
 
-  /* If we are profiling, make sure no instructions are scheduled before
-     the call to mcount.  However, if -fpic, the above call will have
-     done that.  */
-  if (current_function_profile && ! pic_reg_used)
-    emit_insn (gen_blockage ());
+  /* Prevent function calls from be scheduled before the call to mcount.
+     In the pic_reg_used case, make sure that the got load isn't deleted.  */
+  if (current_function_profile)
+    emit_insn (gen_blockage (pic_reg_used ? pic_offset_table_rtx : const0_rtx));
 }
 
 /* Emit code to restore saved registers using MOV insns.  First register
@@ -5245,7 +5246,8 @@ legitimize_pic_address (orig, reg)
 	  /* This symbol may be referenced via a displacement from the PIC
 	     base address (@GOTOFF).  */
 
-	  current_function_uses_pic_offset_table = 1;
+	  if (reload_in_progress)
+	    regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;
 	  new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTOFF);
 	  new = gen_rtx_CONST (Pmode, new);
 	  new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, new);
@@ -5261,7 +5263,6 @@ legitimize_pic_address (orig, reg)
     {
       if (TARGET_64BIT)
 	{
-	  current_function_uses_pic_offset_table = 1;
 	  new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTPCREL);
 	  new = gen_rtx_CONST (Pmode, new);
 	  new = gen_rtx_MEM (Pmode, new);
@@ -5281,7 +5282,8 @@ legitimize_pic_address (orig, reg)
 	  /* This symbol must be referenced via a load from the
 	     Global Offset Table (@GOT).  */
 
-	  current_function_uses_pic_offset_table = 1;
+	  if (reload_in_progress)
+	    regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;
 	  new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOT);
 	  new = gen_rtx_CONST (Pmode, new);
 	  new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, new);
@@ -5322,7 +5324,8 @@ legitimize_pic_address (orig, reg)
 	    {
 	      if (!TARGET_64BIT)
 		{
-		  current_function_uses_pic_offset_table = 1;
+		  if (reload_in_progress)
+		    regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;
 		  new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, op0),
 					UNSPEC_GOTOFF);
 		  new = gen_rtx_PLUS (Pmode, new, op1);
@@ -5518,7 +5521,8 @@ legitimize_address (x, oldx, mode)
         case TLS_MODEL_INITIAL_EXEC:
 	  if (flag_pic)
 	    {
-	      current_function_uses_pic_offset_table = 1;
+	      if (reload_in_progress)
+		regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;
 	      pic = pic_offset_table_rtx;
 	    }
 	  else
@@ -10464,10 +10468,7 @@ ix86_expand_call (retval, fnaddr, callarg1, callarg2, pop)
   if (! TARGET_64BIT && flag_pic
       && GET_CODE (XEXP (fnaddr, 0)) == SYMBOL_REF
       && ! SYMBOL_REF_FLAG (XEXP (fnaddr, 0)))
-    {
-      current_function_uses_pic_offset_table = 1;
-      use_reg (&use, pic_offset_table_rtx);
-    }
+    use_reg (&use, pic_offset_table_rtx);
 
   if (TARGET_64BIT && INTVAL (callarg2) >= 0)
     {
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 5946370..970dfdf 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2406,17 +2406,6 @@ enum ix86_builtins
       fputs (user_label_prefix, FILE);		\
     fputs (xname, FILE);			\
   } while (0)
-
-/* The `FINALIZE_PIC' macro serves as a hook to emit these special
-   codes once the function is being compiled into assembly code, but
-   not before.  (It is not done before, because in the case of
-   compiling an inline function, it would lead to multiple PIC
-   prologues being included in functions which used inline functions
-   and were compiled to assembly language.)  */
-
-#define FINALIZE_PIC \
-  (current_function_uses_pic_offset_table |= current_function_profile)
-
 
 /* Max number of args passed in registers.  If this is more than 3, we will
    have problems with ebx (register #4), since it is a caller save register and
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 2d19645..1c99f60 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -12699,29 +12699,34 @@
 	      (use (label_ref (match_operand 1 "" "")))])]
   ""
 {
-  /* In PIC mode, the table entries are stored GOT-relative.  Convert
-     the relative address to an absolute address.  */
+  /* In PIC mode, the table entries are stored GOT (32-bit) or PC (64-bit)
+     relative.  Convert the relative address to an absolute address.  */
   if (flag_pic)
     {
+      rtx op0, op1;
+      enum rtx_code code;
+
       if (TARGET_64BIT)
-	operands[0] = expand_simple_binop (Pmode, PLUS, operands[0],
-					   gen_rtx_LABEL_REF (Pmode, operands[1]),
-					   NULL_RTX, 0,
-					   OPTAB_DIRECT);
+	{
+	  code = PLUS;
+	  op0 = operands[0];
+	  op1 = gen_rtx_LABEL_REF (Pmode, operands[1]);
+	}
       else if (HAVE_AS_GOTOFF_IN_DATA)
 	{
-	  operands[0] = expand_simple_binop (Pmode, PLUS, operands[0],
-					     pic_offset_table_rtx, NULL_RTX,
-					     1, OPTAB_DIRECT);
-	  current_function_uses_pic_offset_table = 1;
+	  code = PLUS;
+	  op0 = operands[0];
+	  op1 = pic_offset_table_rtx;
 	}
       else
 	{
-	  operands[0] = expand_simple_binop (Pmode, MINUS, pic_offset_table_rtx,
-					     operands[0], NULL_RTX, 1,
-					     OPTAB_DIRECT);
-	  current_function_uses_pic_offset_table = 1;
+	  code = MINUS;
+	  op0 = pic_offset_table_rtx;
+	  op1 = operands[0];
 	}
+
+      operands[0] = expand_simple_binop (Pmode, code, op0, op1, NULL_RTX, 1,
+					 OPTAB_DIRECT);
     }
 })
 
@@ -13061,7 +13066,7 @@
      registers we stored in the result block.  We avoid problems by
      claiming that all hard registers are used and clobbered at this
      point.  */
-  emit_insn (gen_blockage ());
+  emit_insn (gen_blockage (const0_rtx));
 
   DONE;
 })
@@ -13072,7 +13077,7 @@
 ;; all of memory.  This blocks insns from being moved across this point.
 
 (define_insn "blockage"
-  [(unspec_volatile [(const_int 0)] UNSPECV_BLOCKAGE)]
+  [(unspec_volatile [(match_operand 0 "" "")] UNSPECV_BLOCKAGE)]
   ""
   ""
   [(set_attr "length" "0")])
@@ -13391,7 +13396,6 @@
 {
   if (!flag_pic)
     abort ();
-  current_function_uses_pic_offset_table = 1;
   operands[2] = pic_offset_table_rtx;
   operands[3] = ix86_tls_get_addr ();
 })
@@ -13434,7 +13438,6 @@
 {
   if (!flag_pic)
     abort ();
-  current_function_uses_pic_offset_table = 1;
   operands[1] = pic_offset_table_rtx;
   operands[2] = ix86_tls_get_addr ();
 })