Submitted By: Jonathan Norman (jonathan at bluesquarelinux.co.uk)
Date: 2011-07-12
Initial Package Version: 4.6.0
Origin: Upstream
Upstream Status: Applied
Description: Fixes a issue with Mips that causes GCC to setfault
             when using optimation greater than -O0. Taken from
             GCC Revision 174541 and applied to GCC 4.6.0

diff -Naur gcc-4.6.0.orig/gcc/expmed.c gcc-4.6.0/gcc/expmed.c
--- gcc-4.6.0.orig/gcc/expmed.c	2011-07-12 16:18:33.939215981 +0000
+++ gcc-4.6.0/gcc/expmed.c	2011-07-12 16:33:51.121616152 +0000
@@ -1431,7 +1431,7 @@
       unsigned int nwords = (bitsize + (BITS_PER_WORD - 1)) / BITS_PER_WORD;
       unsigned int i;
 
-      if (target == 0 || !REG_P (target))
+      if (target == 0 || !REG_P (target) || !valid_multiword_target_p (target))
 	target = gen_reg_rtx (mode);
 
       /* Indicate for flow that the entire target reg is being set.  */
diff -Naur gcc-4.6.0.orig/gcc/optabs.c gcc-4.6.0/gcc/optabs.c
--- gcc-4.6.0.orig/gcc/optabs.c	2011-07-12 16:18:34.119217377 +0000
+++ gcc-4.6.0/gcc/optabs.c	2011-07-12 16:33:00.296108734 +0000
@@ -1694,7 +1694,10 @@
 
       /* If TARGET is the same as one of the operands, the REG_EQUAL note
 	 won't be accurate, so use a new target.  */
-      if (target == 0 || target == op0 || target == op1)
+      if (target == 0
+	  || target == op0
+	  || target == op1
+	  || !valid_multiword_target_p (target))
 	target = gen_reg_rtx (mode);
 
       start_sequence ();
@@ -1762,7 +1765,10 @@
 
 	  /* If TARGET is the same as one of the operands, the REG_EQUAL note
 	     won't be accurate, so use a new target.  */
-	  if (target == 0 || target == op0 || target == op1)
+	  if (target == 0
+	      || target == op0
+	      || target == op1
+	      || !valid_multiword_target_p (target))
 	    target = gen_reg_rtx (mode);
 
 	  start_sequence ();
@@ -1816,7 +1822,11 @@
 	 opportunities, and second because if target and op0 happen to be MEMs
 	 designating the same location, we would risk clobbering it too early
 	 in the code sequence we generate below.  */
-      if (target == 0 || target == op0 || target == op1 || ! REG_P (target))
+      if (target == 0
+	  || target == op0
+	  || target == op1
+	  || !REG_P (target)
+	  || !valid_multiword_target_p (target))
 	target = gen_reg_rtx (mode);
 
       start_sequence ();
@@ -1936,7 +1946,7 @@
 
       xtarget = gen_reg_rtx (mode);
 
-      if (target == 0 || !REG_P (target))
+      if (target == 0 || !REG_P (target) || !valid_multiword_target_p (target))
 	target = xtarget;
 
       /* Indicate for flow that the entire target reg is being set.  */
@@ -2689,7 +2699,7 @@
   t0 = expand_unop (word_mode, bswap_optab,
 		    operand_subword_force (op, 1, mode), NULL_RTX, true);
 
-  if (target == 0)
+  if (target == 0 || !valid_multiword_target_p (target))
     target = gen_reg_rtx (mode);
   if (REG_P (target))
     emit_clobber (target);
@@ -2932,7 +2942,9 @@
   if (code == ABS)
     mask = double_int_not (mask);
 
-  if (target == 0 || target == op0)
+  if (target == 0
+      || target == op0
+      || (nwords > 1 && !valid_multiword_target_p (target)))
     target = gen_reg_rtx (mode);
 
   if (nwords > 1)
@@ -3140,7 +3152,7 @@
       int i;
       rtx insns;
 
-      if (target == 0 || target == op0)
+      if (target == 0 || target == op0 || !valid_multiword_target_p (target))
 	target = gen_reg_rtx (mode);
 
       start_sequence ();
@@ -3611,7 +3623,10 @@
 
   mask = double_int_setbit (double_int_zero, bitpos);
 
-  if (target == 0 || target == op0 || target == op1)
+  if (target == 0
+      || target == op0
+      || target == op1
+      || (nwords > 1 && !valid_multiword_target_p (target)))
     target = gen_reg_rtx (mode);
 
   if (nwords > 1)
@@ -7330,4 +7345,21 @@
   return NULL_RTX;
 }
 
+/* TARGET is a target of a multiword operation that we are going to
+   implement as a series of word-mode operations.  Return true if
+   TARGET is suitable for this purpose.  */
+
+bool
+valid_multiword_target_p (rtx target)
+{
+  enum machine_mode mode;
+  int i;
+
+  mode = GET_MODE (target);
+  for (i = 0; i < GET_MODE_SIZE (mode); i += UNITS_PER_WORD)
+    if (!validate_subreg (word_mode, mode, target, i))
+      return false;
+  return true;
+}
+
 #include "gt-optabs.h"
diff -Naur gcc-4.6.0.orig/gcc/optabs.h gcc-4.6.0/gcc/optabs.h
--- gcc-4.6.0.orig/gcc/optabs.h	2011-07-12 16:18:34.119217377 +0000
+++ gcc-4.6.0/gcc/optabs.h	2011-07-12 16:24:10.888292947 +0000
@@ -923,4 +923,6 @@
 extern rtx optab_libfunc (optab optab, enum machine_mode mode);
 extern rtx convert_optab_libfunc (convert_optab optab, enum machine_mode mode1,
 			          enum machine_mode mode2);
+
+extern bool valid_multiword_target_p (rtx);
 #endif /* GCC_OPTABS_H */
diff -Naur gcc-4.6.0.orig/gcc/testsuite/gcc.target/mips/pr45074.c gcc-4.6.0/gcc/testsuite/gcc.target/mips/pr45074.c
--- gcc-4.6.0.orig/gcc/testsuite/gcc.target/mips/pr45074.c	1970-01-01 00:00:00.000000000 +0000
+++ gcc-4.6.0/gcc/testsuite/gcc.target/mips/pr45074.c	2011-07-12 16:19:49.925768556 +0000
@@ -0,0 +1,8 @@
+/* { dg-options "-mhard-float -mgp32 -O" } */
+register double g __asm__("$f20");
+
+NOMIPS16 void
+test (double a)
+{
+  g = -a;
+}