Fix powerpc/rs6000 (subreg:SF (mem:SI ...)) reload problem.

	* reload.c (push_reload): In WORD_REGISTER_OPERATIONS code, add test
	to require the SUBREG mode to be smaller than the SUBREG_REG mode.
	* reload1.c (eliminate_regs): Likewise.

From-SVN: r17444

gcc/ChangeLog

+Thu Jan 22 14:47:31 1998  Jim Wilson  <wilson@cygnus.com>
+
+	* reload.c (push_reload): In WORD_REGISTER_OPERATIONS code, add test
+	to require the SUBREG mode to be smaller than the SUBREG_REG mode.
+	* reload1.c (eliminate_regs): Likewise.
+
 Thu Jan 22 14:49:14 1998  Jeffrey A Law  (law@cygnus.com)
 
 	* regmove.c (find_matches): Initialize matches->earlyclobber too.

gcc/reload.c

@@ -987,9 +987,11 @@ push_reload (in, out, inloc, outloc, class,
 	      && ((GET_MODE_SIZE (outmode)
 		   > GET_MODE_SIZE (GET_MODE (SUBREG_REG (out))))
 #ifdef WORD_REGISTER_OPERATIONS
-		  || ((GET_MODE_SIZE (outmode) - 1) / UNITS_PER_WORD ==
-		      ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (out))) - 1)
-		       / UNITS_PER_WORD))
+		  || ((GET_MODE_SIZE (outmode)
+		       < GET_MODE_SIZE (GET_MODE (SUBREG_REG (out))))
+		      && ((GET_MODE_SIZE (outmode) - 1) / UNITS_PER_WORD ==
+			  ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (out))) - 1)
+			   / UNITS_PER_WORD)))
 #endif
 	          ))
 	  || (GET_CODE (SUBREG_REG (out)) == REG

gcc/reload1.c

@@ -3122,17 +3122,19 @@ eliminate_regs (x, mem_mode, insn)
 	  int new_size = GET_MODE_SIZE (GET_MODE (new));
 
 	  if (GET_CODE (new) == MEM
-	      && x_size <= new_size
+	      && ((x_size < new_size
 #ifdef WORD_REGISTER_OPERATIONS
-	      /* On these machines, combine can create rtl of the form
-		   (set (subreg:m1 (reg:m2 R) 0) ...)
-		 where m1 < m2, and expects something interesting to 
-		 happen to the entire word.  Moreover, it will use the
-		 (reg:m2 R) later, expecting all bits to be preserved.
-		 So if the number of words is the same, preserve the 
-		 subreg so that push_reloads can see it.  */
-	      && ! ((x_size-1)/UNITS_PER_WORD == (new_size-1)/UNITS_PER_WORD)
+		   /* On these machines, combine can create rtl of the form
+		      (set (subreg:m1 (reg:m2 R) 0) ...)
+		      where m1 < m2, and expects something interesting to 
+		      happen to the entire word.  Moreover, it will use the
+		      (reg:m2 R) later, expecting all bits to be preserved.
+		      So if the number of words is the same, preserve the 
+		      subreg so that push_reloads can see it.  */
+		   && ! ((x_size-1)/UNITS_PER_WORD == (new_size-1)/UNITS_PER_WORD)
 #endif
+		   )
+		  || (x_size == new_size))
 #ifdef LOAD_EXTEND_OP
 	      /* On these machines we will be reloading what is
 		 inside the SUBREG if it originally was a pseudo and