From: Bernd Schmidt <crux@ohara.Informatik.RWTH-Aachen.DE>
Date: Wed, 6 Jan 1999 23:43:14 +0000 (-0700)
Subject: combine.c (num_sign_bit_copies): In NEG...
X-Git-Tag: prereleases/egcs-1.1.2-prerelease-1~42
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a08c4828452472925881831c5ffa23ec97a2ba3;p=thirdparty%2Fgcc.git

combine.c (num_sign_bit_copies): In NEG...

        * combine.c (num_sign_bit_copies): In NEG, MULT, DIV and MOD cases,
        when a test can't be performed due to limited width of
        HOST_BITS_PER_WIDE_INT, use the more conservative approximation.
        Fix UDIV case for cases where the first operand has the highest bit
        set.
And fix a couple copyrights.

From-SVN: r24549
---

diff --git a/gcc/combine.c b/gcc/combine.c
index 374cd3da6f4a..db9bb381d852 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -1,5 +1,5 @@
 /* Optimize by combining instructions for GNU compiler.
-   Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc.
 
 This file is part of GNU CC.
 
@@ -7994,13 +7994,15 @@ num_sign_bit_copies (x, mode)
 	 is known to be positive, the number of sign bit copies is the
 	 same as that of the input.  Finally, if the input has just one bit
 	 that might be nonzero, all the bits are copies of the sign bit.  */
+      num0 = num_sign_bit_copies (XEXP (x, 0), mode);
+      if (bitwidth > HOST_BITS_PER_WIDE_INT)
+	return num0 > 1 ? num0 - 1 : 1;
+
       nonzero = nonzero_bits (XEXP (x, 0), mode);
       if (nonzero == 1)
 	return bitwidth;
 
-      num0 = num_sign_bit_copies (XEXP (x, 0), mode);
       if (num0 > 1
-	  && bitwidth <= HOST_BITS_PER_WIDE_INT
 	  && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero))
 	num0--;
 
@@ -8044,19 +8046,27 @@ num_sign_bit_copies (x, mode)
 
       result = bitwidth - (bitwidth - num0) - (bitwidth - num1);
       if (result > 0
-	  && bitwidth <= HOST_BITS_PER_WIDE_INT
-	  && ((nonzero_bits (XEXP (x, 0), mode)
-	       & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
-	  && ((nonzero_bits (XEXP (x, 1), mode)
-	      & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (((nonzero_bits (XEXP (x, 0), mode)
+		    & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+		  && ((nonzero_bits (XEXP (x, 1), mode)
+		       & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))))
 	result--;
 
       return MAX (1, result);
 
     case UDIV:
-      /* The result must be <= the first operand.  */
-      return num_sign_bit_copies (XEXP (x, 0), mode);
-
+      /* The result must be <= the first operand.  If the first operand
+         has the high bit set, we know nothing about the number of sign
+         bit copies.  */
+      if (bitwidth > HOST_BITS_PER_WIDE_INT)
+	return 1;
+      else if ((nonzero_bits (XEXP (x, 0), mode)
+		& ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+	return 1;
+      else
+	return num_sign_bit_copies (XEXP (x, 0), mode);
+				    
     case UMOD:
       /* The result must be <= the scond operand.  */
       return num_sign_bit_copies (XEXP (x, 1), mode);
@@ -8067,20 +8077,20 @@ num_sign_bit_copies (x, mode)
 	 to add 1.  */
       result = num_sign_bit_copies (XEXP (x, 0), mode);
       if (result > 1
-	  && bitwidth <= HOST_BITS_PER_WIDE_INT
-	  && (nonzero_bits (XEXP (x, 1), mode)
-	      & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
-	result --;
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (nonzero_bits (XEXP (x, 1), mode)
+		  & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+	result--;
 
       return result;
 
     case MOD:
       result = num_sign_bit_copies (XEXP (x, 1), mode);
       if (result > 1
-	  && bitwidth <= HOST_BITS_PER_WIDE_INT
-	  && (nonzero_bits (XEXP (x, 1), mode)
-	      & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
-	result --;
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (nonzero_bits (XEXP (x, 1), mode)
+		  & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+	result--;
 
       return result;
 
diff --git a/gcc/config/h8300/h8300.h b/gcc/config/h8300/h8300.h
index d160f64ecf22..25c95f3f3f29 100644
--- a/gcc/config/h8300/h8300.h
+++ b/gcc/config/h8300/h8300.h
@@ -1,6 +1,6 @@
 /* Definitions of target machine for GNU compiler. 
    Hitachi H8/300 version generating coff 
-   Copyright (C) 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
+   Copyright (C) 1992, 93-98, 1999 Free Software Foundation, Inc.
    Contributed by Steve Chamberlain (sac@cygnus.com),
    Jim Wilson (wilson@cygnus.com), and Doug Evans (dje@cygnus.com).
 
diff --git a/gcc/expr.c b/gcc/expr.c
index 18abfc6d05c4..7f364adb3288 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1,5 +1,5 @@
 /* Convert tree expression to rtl instructions, for GNU compiler.
-   Copyright (C) 1988, 92-97, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1988, 92-98, 1999 Free Software Foundation, Inc.
 
 This file is part of GNU CC.