* doc/rtl.texi (const_double): Document as sign-extending.

	* expmed.c (expand_mult): Ensure we don't use shift
	incorrectly.
	* emit-rtl.c (immed_double_int_const): Refine to state the
	value is signed.
	* simplify-rtx.c (mode_signbit_p): Add a fixme for wider than
	CONST_DOUBLE integers.
	(simplify_const_unary_operation, UNSIGNED_FLOAT): Ensure no
	negative values are converted.  Fix conversions bigger than
	HOST_BITS_PER_WIDE_INT.
	(simplify_binary_operation_1): Ensure we don't use shift
	incorrectly.
	(simplify_immed_subreg): Sign-extend CONST_DOUBLEs.
	* explow.c (plus_constant_mode): Add.
	(plus_constant): Implement with plus_constant_mode.
	* rtl.h (plus_constant_mode): Add.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@186147 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 16 insertions, 16 deletions

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 35b7f2cdd29..1d82a375673 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -97,6 +97,7 @@ mode_signbit_p (enum machine_mode mode, const_rtx x)
       width -= HOST_BITS_PER_WIDE_INT;
     }
   else
+    /* FIXME: We don't yet have a representation for wider modes.  */
     return false;
 
   if (width < HOST_BITS_PER_WIDE_INT)
@@ -1355,16 +1356,11 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode,
       else
 	lv = CONST_DOUBLE_LOW (op),  hv = CONST_DOUBLE_HIGH (op);
 
-      if (op_mode == VOIDmode)
-	{
-	  /* We don't know how to interpret negative-looking numbers in
-	     this case, so don't try to fold those.  */
-	  if (hv < 0)
-	    return 0;
-	}
-      else if (GET_MODE_PRECISION (op_mode) >= HOST_BITS_PER_WIDE_INT * 2)
-	;
-      else
+      if (op_mode == VOIDmode
+	  || GET_MODE_PRECISION (op_mode) > 2 * HOST_BITS_PER_WIDE_INT)
+	/* We should never get a negative number.  */
+	gcc_assert (hv >= 0);
+      else if (GET_MODE_PRECISION (op_mode) <= HOST_BITS_PER_WIDE_INT)
 	hv = 0, lv &= GET_MODE_MASK (op_mode);
 
       REAL_VALUE_FROM_UNSIGNED_INT (d, lv, hv, mode);
@@ -1718,7 +1714,7 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode,
   else if (GET_CODE (op) == CONST_DOUBLE
 	   && SCALAR_FLOAT_MODE_P (GET_MODE (op))
 	   && GET_MODE_CLASS (mode) == MODE_INT
-	   && width <= 2*HOST_BITS_PER_WIDE_INT && width > 0)
+	   && width <= 2 * HOST_BITS_PER_WIDE_INT && width > 0)
     {
       /* Although the overflow semantics of RTL's FIX and UNSIGNED_FIX
 	 operators are intentionally left unspecified (to ease implementation
@@ -1783,7 +1779,7 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode,
 	    return const0_rtx;
 
 	  /* Test against the unsigned upper bound.  */
-	  if (width == 2*HOST_BITS_PER_WIDE_INT)
+	  if (width == 2 * HOST_BITS_PER_WIDE_INT)
 	    {
 	      th = -1;
 	      tl = -1;
@@ -2380,7 +2376,9 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 	      || GET_MODE_CLASS (GET_MODE (trueop1)) == MODE_INT)
 	  && GET_MODE (op0) == mode
 	  && CONST_DOUBLE_LOW (trueop1) == 0
-	  && (val = exact_log2 (CONST_DOUBLE_HIGH (trueop1))) >= 0)
+	  && (val = exact_log2 (CONST_DOUBLE_HIGH (trueop1))) >= 0
+	  && (val < 2 * HOST_BITS_PER_WIDE_INT - 1
+	      || GET_MODE_BITSIZE (mode) <= 2 * HOST_BITS_PER_WIDE_INT))
 	return simplify_gen_binary (ASHIFT, mode, op0,
 				    GEN_INT (val + HOST_BITS_PER_WIDE_INT));
 
@@ -5189,6 +5187,7 @@ simplify_immed_subreg (enum machine_mode outermode, rtx op,
 	case CONST_DOUBLE:
 	  if (GET_MODE (el) == VOIDmode)
 	    {
+	      unsigned char extend = 0;
 	      /* If this triggers, someone should have generated a
 		 CONST_INT instead.  */
 	      gcc_assert (elem_bitsize > HOST_BITS_PER_WIDE_INT);
@@ -5201,10 +5200,11 @@ simplify_immed_subreg (enum machine_mode outermode, rtx op,
 		    = CONST_DOUBLE_HIGH (el) >> (i - HOST_BITS_PER_WIDE_INT);
 		  i += value_bit;
 		}
-	      /* It shouldn't matter what's done here, so fill it with
-		 zero.  */
+
+	      if (CONST_DOUBLE_HIGH (el) >> (HOST_BITS_PER_WIDE_INT - 1))
+		extend = -1;
 	      for (; i < elem_bitsize; i += value_bit)
-		*vp++ = 0;
+		*vp++ = extend;
 	    }
 	  else
 	    {