loop.c (move_movables): Note issues with replacing REGs with SUBREGs.

�
        * loop.c (move_movables): Note issues with replacing REGs with
        SUBREGs.
        * mips.h (GO_IF_LEGITIMATE_ADDRESS): Handle SUBREGs properly.

From-SVN: r27573

gcc/ChangeLog

+Thu Jun 17 14:25:08 1999  Jeffrey A Law  (law@cygnus.com)
+
+	* loop.c (move_movables): Note issues with replacing REGs with
+	SUBREGs.
+	* mips.h (GO_IF_LEGITIMATE_ADDRESS): Handle SUBREGs properly.
+
 Thu Jun 17 13:28:30 1999  David O'Brien <obrien@FreeBSD.org>
 
 	* i386/freebsd-elf.h (LINK_SPEC): Fix typo.

gcc/config/mips/mips.h

@@ -2858,6 +2858,9 @@ typedef struct mips_args {
       GO_DEBUG_RTX (xinsn);						\
     }									\
 									\
+  while (GET_CODE (xinsn) == SUBREG)					\
+    xinsn = SUBREG_REG (xinsn);						\
+									\
   /* The mips16 can only use the stack pointer as a base register when	\
      loading SImode or DImode values.  */				\
   if (GET_CODE (xinsn) == REG && REG_MODE_OK_FOR_BASE_P (xinsn, MODE))	\
@@ -2873,6 +2876,8 @@ typedef struct mips_args {
       register rtx xlow0 = XEXP (xinsn, 0);				\
       register rtx xlow1 = XEXP (xinsn, 1);				\
 									\
+      while (GET_CODE (xlow0) == SUBREG)				\
+	xlow0 = SUBREG_REG (xlow0);					\
       if (GET_CODE (xlow0) == REG					\
 	  && REG_MODE_OK_FOR_BASE_P (xlow0, MODE)			\
 	  && mips_check_split (xlow1, MODE))				\
@@ -2883,8 +2888,16 @@ typedef struct mips_args {
     {									\
       register rtx xplus0 = XEXP (xinsn, 0);				\
       register rtx xplus1 = XEXP (xinsn, 1);				\
-      register enum rtx_code code0 = GET_CODE (xplus0);			\
-      register enum rtx_code code1 = GET_CODE (xplus1);			\
+      register enum rtx_code code0;					\
+      register enum rtx_code code1;					\
+									\
+      while (GET_CODE (xplus0) == SUBREG)				\
+	xplus0 = SUBREG_REG (xplus0);					\
+      code0 = GET_CODE (xplus0);					\
+									\
+      while (GET_CODE (xplus1) == SUBREG)				\
+	xplus1 = SUBREG_REG (xplus1);					\
+      code1 = GET_CODE (xplus1);					\
 									\
       /* The mips16 can only use the stack pointer as a base register	\
          when loading SImode or DImode values.  */			\

gcc/loop.c

@@ -2170,7 +2170,14 @@ move_movables (movables, threshold, insn_count, loop_start, end, nregs)
 		      /* Schedule the reg loaded by M1
 			 for replacement so that shares the reg of M.
 			 If the modes differ (only possible in restricted
-			 circumstances, make a SUBREG.  */
+			 circumstances, make a SUBREG.
+
+			 Note this assumes that the target dependent files
+			 treat REG and SUBREG equally, including within
+			 GO_IF_LEGITIMATE_ADDRESS and in all the
+			 predicates since we never verify that replacing the
+			 original register with a SUBREG results in a
+			 recognizable insn.  */
 		      if (GET_MODE (m->set_dest) == GET_MODE (m1->set_dest))
 			reg_map[m1->regno] = m->set_dest;
 		      else