Fix alpha-linux core dump reported by H.J. Lu.

	* alpha/alpha.h (PREFERRED_RELOAD_CLASS): Return NO_REGS if NO_REGS
	is passed in.
	* emit-rtl.c (gen_lowpart_common): Add code to convert CONST_INT to
	SFmode for 64 bit hosts.

From-SVN: r15035

gcc/ChangeLog

+Tue Sep  2 12:00:36 1997  Jim Wilson  <wilson@cygnus.com>
+
+	* alpha/alpha.h (PREFERRED_RELOAD_CLASS): Return NO_REGS if NO_REGS
+	is passed in.
+	* emit-rtl.c (gen_lowpart_common): Add code to convert CONST_INT to
+	SFmode for 64 bit hosts.
+	
 Tue Sep  2 13:42:38 1997  Paul N. Hilfinger  <hilfingr@CS.Berkeley.EDU>
 
 	* fixincludes: Permits spaces between # and define.  Discard C++

gcc/config/alpha/alpha.h

@@ -691,7 +691,7 @@ enum reg_class { NO_REGS, GENERAL_REGS, FLOAT_REGS, ALL_REGS,
 
 #define PREFERRED_RELOAD_CLASS(X, CLASS)		\
   (CONSTANT_P (X) && (X) != const0_rtx && (X) != CONST0_RTX (GET_MODE (X)) \
-   ? ((CLASS) == FLOAT_REGS ? NO_REGS : GENERAL_REGS)			\
+   ? ((CLASS) == FLOAT_REGS || (CLASS) == NO_REGS ? NO_REGS : GENERAL_REGS)\
    : (CLASS))
 
 /* Loading and storing HImode or QImode values to and from memory

gcc/emit-rtl.c

@@ -809,6 +809,26 @@ gen_lowpart_common (mode, x)
       return CONST_DOUBLE_FROM_REAL_VALUE (u.d, mode);
     }
 #endif
+
+  /* We need an extra case for machines where HOST_BITS_PER_WIDE_INT is the
+     same as sizeof (double), such as the alpha.  We only handle the
+     REAL_ARITHMETIC case, which is easy.  Testing HOST_BITS_PER_WIDE_INT
+     is not strictly necessary, but is done to restrict this code to cases
+     where it is known to work.  */
+#ifdef REAL_ARITHMETIC
+  else if (mode == SFmode
+	   && GET_CODE (x) == CONST_INT
+	   && GET_MODE_BITSIZE (mode) * 2 == HOST_BITS_PER_WIDE_INT)
+    {
+      REAL_VALUE_TYPE r;
+      HOST_WIDE_INT i;
+
+      i = INTVAL (x);
+      r = REAL_VALUE_FROM_TARGET_SINGLE (i);
+      return CONST_DOUBLE_FROM_REAL_VALUE (r, mode);
+    }
+#endif
+
   /* Similarly, if this is converting a floating-point value into a
      single-word integer.  Only do this is the host and target parameters are
      compatible.  */