gas: invoke md_optimize_expr() also for unary expressions

Give backends a chance to see these, just as they can see binary ones.
Most of those which use this hook already cope with NULL being passed
for the left operand (typically because of checking the operator first).
Adjust the two which don't.

Take the opportunity and also document the hook.

1 files changed, 28 insertions, 19 deletions

diff --git a/gas/expr.c b/gas/expr.c
index b83296c..204cfeb 100644
--- a/gas/expr.c
+++ b/gas/expr.c
@@ -764,6 +764,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
   symbolS *symbolP;	/* Points to symbol.  */
   char *name;		/* Points to name of symbol.  */
   segT segment;
+  operatorT op = O_absent; /* For unary operators.  */
 
   /* All integers are regarded as unsigned unless they are negated.
      This is because the only thing which cares whether a number is
@@ -1029,19 +1030,33 @@ operand (expressionS *expressionP, enum expr_mode mode)
       /* '~' is permitted to start a label on the Delta.  */
       if (is_name_beginner (c))
 	goto isname;
-      /* Fall through.  */
+      op = O_bit_not;
+      goto unary;
+
     case '!':
+      op = O_logical_not;
+      goto unary;
+
     case '-':
+      op = O_uminus;
+      /* Fall through.  */
     case '+':
       {
-#ifdef md_operator
       unary:
-#endif
 	operand (expressionP, mode);
+
+#ifdef md_optimize_expr
+	if (md_optimize_expr (NULL, op, expressionP))
+	{
+	  /* Skip.  */
+	  ;
+	}
+	else
+#endif
 	if (expressionP->X_op == O_constant)
 	  {
 	    /* input_line_pointer -> char after operand.  */
-	    if (c == '-')
+	    if (op == O_uminus)
 	      {
 		expressionP->X_add_number
 		  = - (addressT) expressionP->X_add_number;
@@ -1052,13 +1067,13 @@ operand (expressionS *expressionP, enum expr_mode mode)
 		if (expressionP->X_add_number)
 		  expressionP->X_extrabit ^= 1;
 	      }
-	    else if (c == '~' || c == '"')
+	    else if (op == O_bit_not)
 	      {
 		expressionP->X_add_number = ~ expressionP->X_add_number;
 		expressionP->X_extrabit ^= 1;
 		expressionP->X_unsigned = 0;
 	      }
-	    else if (c == '!')
+	    else if (op == O_logical_not)
 	      {
 		expressionP->X_add_number = ! expressionP->X_add_number;
 		expressionP->X_unsigned = 1;
@@ -1067,7 +1082,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
 	  }
 	else if (expressionP->X_op == O_big
 		 && expressionP->X_add_number <= 0
-		 && c == '-'
+		 && op == O_uminus
 		 && (generic_floating_point_number.sign == '+'
 		     || generic_floating_point_number.sign == 'P'))
 	  {
@@ -1082,7 +1097,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
 	  {
 	    int i;
 
-	    if (c == '~' || c == '-')
+	    if (op == O_uminus || op == O_bit_not)
 	      {
 		for (i = 0; i < expressionP->X_add_number; ++i)
 		  generic_bignum[i] = ~generic_bignum[i];
@@ -1095,7 +1110,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
 		      generic_bignum[i] = ~(LITTLENUM_TYPE) 0;
 		  }
 
-		if (c == '-')
+		if (op == O_uminus)
 		  for (i = 0; i < expressionP->X_add_number; ++i)
 		    {
 		      generic_bignum[i] += 1;
@@ -1103,7 +1118,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
 			break;
 		    }
 	      }
-	    else if (c == '!')
+	    else if (op == O_logical_not)
 	      {
 		for (i = 0; i < expressionP->X_add_number; ++i)
 		  if (generic_bignum[i] != 0)
@@ -1117,15 +1132,10 @@ operand (expressionS *expressionP, enum expr_mode mode)
 	else if (expressionP->X_op != O_illegal
 		 && expressionP->X_op != O_absent)
 	  {
-	    if (c != '+')
+	    if (op != O_absent)
 	      {
 		expressionP->X_add_symbol = make_expr_symbol (expressionP);
-		if (c == '-')
-		  expressionP->X_op = O_uminus;
-		else if (c == '~' || c == '"')
-		  expressionP->X_op = O_bit_not;
-		else
-		  expressionP->X_op = O_logical_not;
+		expressionP->X_op = op;
 		expressionP->X_add_number = 0;
 	      }
 	    else if (!md_register_arithmetic && expressionP->X_op == O_register)
@@ -1288,8 +1298,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
 
 #ifdef md_operator
 	  {
-	    operatorT op = md_operator (name, 1, &c);
-
+	    op = md_operator (name, 1, &c);
 	    switch (op)
 	      {
 	      case O_uminus: