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* RFA: Fix ICE on PARALLEL returns when expand builtins
@ 2012-12-23  9:44 Richard Sandiford
  2012-12-26 21:33 ` Andrew Pinski
  2013-01-02 15:00 ` Richard Biener
  0 siblings, 2 replies; 10+ messages in thread
From: Richard Sandiford @ 2012-12-23  9:44 UTC (permalink / raw)
  To: gcc-patches

Some of the maths builtins can expand to a call followed by a bit
of postprocessing.  With 4.8's PARALLEL return optimisations, these
embedded calls might return a PARALLEL of pseudos, but the postprocessing
isn't prepared to deal with that.  This leads to an ICE in builtins-53.c
on n32 and n64 mips64-linux-gnu.

One fix might have been to pass an explicit register target to the
expand routines, but that target's only a hint.  This patch instead
adds an avoid_group_rtx function (named after gen_group_rtx) to convert
PARALLELs to pseudos where necessary.

I wondered whether it was really safe for expand_builtin_int_roundingfn_2
to pass "target == const0_rtx" as the "ignore" parameter to expand_call,
given that we don't actually ignore the return value ourselves
(even if the caller does).  I suppose it is safe though,
since expand_call will always return const0_rtx in that case,
and this code is dealing with integer return values.

Tested on mips64-linux-gnu.  OK to install?  Or is there a better way?

Richard


gcc/
	* expr.h (avoid_group_rtx): Declare.
	* expr.c (avoid_group_rtx): New function.
	* builtins.c (expand_builtin_int_roundingfn): Call it.
	(expand_builtin_int_roundingfn_2): Likewise.

Index: gcc/expr.h
===================================================================
--- gcc/expr.h	2012-12-23 09:21:21.969086853 +0000
+++ gcc/expr.h	2012-12-23 09:32:03.487440220 +0000
@@ -334,6 +334,8 @@ extern rtx emit_group_move_into_temps (r
    PARALLEL.  */
 extern void emit_group_store (rtx, rtx, tree, int);
 
+extern rtx avoid_group_rtx (rtx, tree);
+
 /* Copy BLKmode object from a set of registers.  */
 extern void copy_blkmode_from_reg (rtx, rtx, tree);
 
Index: gcc/expr.c
===================================================================
--- gcc/expr.c	2012-12-23 09:21:21.980086911 +0000
+++ gcc/expr.c	2012-12-23 09:32:03.485440208 +0000
@@ -2079,6 +2079,23 @@ emit_group_store (rtx orig_dst, rtx src,
     emit_move_insn (orig_dst, dst);
 }
 
+/* Return a form of X that does not use a PARALLEL.  TYPE is the type
+   of the value stored in X.  */
+
+rtx
+avoid_group_rtx (rtx x, tree type)
+{
+  enum machine_mode mode = TYPE_MODE (type);
+  gcc_checking_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
+  if (GET_CODE (x) == PARALLEL)
+    {
+      rtx result = gen_reg_rtx (mode);
+      emit_group_store (result, x, type, int_size_in_bytes (type));
+      return result;
+    }
+  return x;
+}
+
 /* Copy a BLKmode object of TYPE out of a register SRCREG into TARGET.
 
    This is used on targets that return BLKmode values in registers.  */
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c	2012-12-23 09:21:21.981086916 +0000
+++ gcc/builtins.c	2012-12-23 09:34:47.813323158 +0000
@@ -2757,6 +2757,7 @@ expand_builtin_int_roundingfn (tree exp,
   exp = build_call_nofold_loc (EXPR_LOCATION (exp), fallback_fndecl, 1, arg);
 
   tmp = expand_normal (exp);
+  tmp = avoid_group_rtx (tmp, TREE_TYPE (exp));
 
   /* Truncate the result of floating point optab to integer
      via expand_fix ().  */
@@ -2860,6 +2861,7 @@ expand_builtin_int_roundingfn_2 (tree ex
 				   fallback_fndecl, 1, arg);
 
       target = expand_call (exp, NULL_RTX, target == const0_rtx);
+      target = avoid_group_rtx (target, TREE_TYPE (exp));
       return convert_to_mode (mode, target, 0);
     }
 

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2013-01-09 18:20 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-12-23  9:44 RFA: Fix ICE on PARALLEL returns when expand builtins Richard Sandiford
2012-12-26 21:33 ` Andrew Pinski
2013-01-02 15:00 ` Richard Biener
2013-01-02 16:36   ` Richard Sandiford
2013-01-03  9:14     ` Richard Biener
2013-01-03 18:43       ` Richard Sandiford
2013-01-04 10:56         ` Richard Biener
2013-01-04 18:58           ` Eric Botcazou
2013-01-05 15:31             ` Richard Biener
2013-01-09 18:20               ` Richard Sandiford

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