Fix PR 71873 - ICE in push_reload

Extend computation of subreg_in_class to constants and plus expressions 
inside SUBREGs, before recursively calling push_reload. SYMBOL_REFs are
also CONSTANT_P, so remove explicit handling of SYMBOL_REFs.

gcc/ChangeLog

	PR target/71873
	* reload.c (push_reload): Compute subreg_in_class for
	subregs of constants and plus expressions. Remove special
	handling of SYMBOL_REFs.

gcc/testsuite/ChangeLog

	PR target/71873
	* gcc.target/avr/pr71873.c: New test.

From-SVN: r239321

gcc/ChangeLog

+2016-08-10  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>
+
+	PR target/71873
+	* reload.c (push_reload): Compute subreg_in_class for
+	subregs of constants and plus expressions. Remove special
+	handling of SYMBOL_REFs.
+
 2016-08-10  Alan Modra  <amodra@gmail.com>
 
 	PR target/71680

gcc/reload.c

@@ -1141,7 +1141,8 @@ push_reload (rtx in, rtx out, rtx *inloc, rtx *outloc,
 						   SUBREG_BYTE (in),
 						   GET_MODE (in)),
 			      REGNO (SUBREG_REG (in)));
-      else if (GET_CODE (SUBREG_REG (in)) == SYMBOL_REF)
+      else if (CONSTANT_P (SUBREG_REG (in))
+               || GET_CODE (SUBREG_REG (in)) == PLUS)
 	subreg_in_class = find_valid_class_1 (inmode,
 					      GET_MODE (SUBREG_REG (in)),
 					      rclass);

gcc/testsuite/ChangeLog

+2016-08-10  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>
+
+	PR target/71873
+	* gcc.target/avr/pr71873.c: New test.
+
 2016-08-09  Martin Liska  <mliska@suse.cz>
 
 	* g++.dg/gcov/gcov-dump-1.C: New test.

gcc/testsuite/gcc.target/avr/pr71873.c

+/* { dg-do compile } */
+/* { dg-options "-Os -fcaller-saves" } */
+
+#include <stdint.h>
+
+typedef struct {
+  uint8_t x;
+  uint32_t y;
+} A;
+
+A a;
+
+extern int bar(int);
+extern int foo (char *s, ...);
+
+extern uint8_t param;
+extern uint8_t h,m,s,ld,lm;
+extern uint16_t d;
+
+void gps_parse_string(int z)
+{
+  while (bar(z))
+  {
+    switch (param)
+    {
+      case 0: foo("a", &h, &m, &s, &d); break;
+      case 1: foo("d", &ld, &lm, &a.y); break;
+    }
+  }
+}