[ARC] Allow r30 to be used by the reg-alloc.

gcc/
2018-06-01  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_conditional_register_usage): Allow r30 to
	be used by the reg-alloc.

From-SVN: r248778

gcc/ChangeLog

 2017-06-01  Claudiu Zissulescu  <claziss@synopsys.com>
 
+	* config/arc/arc.c (arc_conditional_register_usage): Allow r30 to
+	be used by the reg-alloc.
+
+2017-06-01  Claudiu Zissulescu  <claziss@synopsys.com>
+
 	* config/arc/arc.md (mulsi3): Avoid use of hard registers before
 	reg-alloc when having mul64 or mul32x16 instructions.
 	(mulsidi3): Likewise.

gcc/config/arc/arc.c

@@ -1548,7 +1548,14 @@ arc_conditional_register_usage (void)
       /* For ARCv2 the core register set is changed.  */
       strcpy (rname29, "ilink");
       strcpy (rname30, "r30");
-      fixed_regs[30] = call_used_regs[30] = 1;
+      call_used_regs[30] = 1;
+      fixed_regs[30] = 0;
+
+      arc_regno_reg_class[30] = WRITABLE_CORE_REGS;
+      SET_HARD_REG_BIT (reg_class_contents[WRITABLE_CORE_REGS], 30);
+      SET_HARD_REG_BIT (reg_class_contents[CHEAP_CORE_REGS], 30);
+      SET_HARD_REG_BIT (reg_class_contents[GENERAL_REGS], 30);
+      SET_HARD_REG_BIT (reg_class_contents[MPY_WRITABLE_CORE_REGS], 30);
    }
 
   if (TARGET_MUL64_SET)

gcc/config/arc/arc.h

@@ -641,7 +641,8 @@ extern enum reg_class arc_regno_reg_class[];
   ((REGNO) < 29 || ((REGNO) == ARG_POINTER_REGNUM) || ((REGNO) == 63)	\
    || ((unsigned) reg_renumber[REGNO] < 29)				\
    || ((unsigned) (REGNO) == (unsigned) arc_tp_regno)			\
-   || (fixed_regs[REGNO] == 0 && IN_RANGE (REGNO, 32, 59)))
+   || (fixed_regs[REGNO] == 0 && IN_RANGE (REGNO, 32, 59))		\
+   || ((REGNO) == 30 && fixed_regs[REGNO] == 0))
 
 #define REGNO_OK_FOR_INDEX_P(REGNO) REGNO_OK_FOR_BASE_P(REGNO)