(simplify_unary_operation): Sign-extend constants when they have the most significant bit set for the target.

(simplify_unary_operation): Sign-extend constants when
they have the most significant bit set for the target.
(simplify_binary_operation): Likewise.

From-SVN: r9309

1 files changed, 26 insertions, 0 deletions

diff --git a/gcc/cse.c b/gcc/cse.c
index 7a0aba8..b9da905 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -3266,6 +3266,19 @@ simplify_unary_operation (code, mode, op, op_mode)
 	      != ((HOST_WIDE_INT) (-1) << (width - 1))))
 	val &= ((HOST_WIDE_INT) 1 << width) - 1;
 
+      /* If this would be an entire word for the target, but is not for
+	 the host, then sign-extend on the host so that the number will look
+	 the same way on the host that it would on the target.
+
+	 For example, when building a 64 bit alpha hosted 32 bit sparc
+	 targeted compiler, then we want the 32 bit unsigned value -1 to be
+	 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
+	 The later confuses the sparc backend.  */
+
+      if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width
+	  && (val & ((HOST_WIDE_INT) 1 << (width - 1))))
+	val |= ((HOST_WIDE_INT) (-1) << width);
+
       return GEN_INT (val);
     }
 #endif
@@ -4126,6 +4139,19 @@ simplify_binary_operation (code, mode, op0, op1)
 	  != ((HOST_WIDE_INT) (-1) << (width - 1))))
     val &= ((HOST_WIDE_INT) 1 << width) - 1;
 
+  /* If this would be an entire word for the target, but is not for
+     the host, then sign-extend on the host so that the number will look
+     the same way on the host that it would on the target.
+
+     For example, when building a 64 bit alpha hosted 32 bit sparc
+     targeted compiler, then we want the 32 bit unsigned value -1 to be
+     represented as a 64 bit value -1, and not as 0x00000000ffffffff.
+     The later confuses the sparc backend.  */
+
+  if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width
+      && (val & ((HOST_WIDE_INT) 1 << (width - 1))))
+    val |= ((HOST_WIDE_INT) (-1) << width);
+
   return GEN_INT (val);
 }