Index: tools/Makefile.gnuhost
===================================================================
RCS file: /cvsroot/src/tools/Makefile.gnuhost,v
retrieving revision 1.45
diff -u -r1.45 Makefile.gnuhost
--- tools/Makefile.gnuhost	13 Apr 2018 06:15:26 -0000	1.45
+++ tools/Makefile.gnuhost	15 Apr 2018 21:44:50 -0000
@@ -20,11 +20,6 @@
 # Disable use of pre-compiled headers on Darwin.
 # GCC build exceeds the macOS clang default bracket nesting level of 256.
 BUILD_OSTYPE!= uname -s
-.if ${BUILD_OSTYPE} == "Darwin"
-HOST_CFLAGS+=-O2 -no-cpp-precomp
-HOST_CFLAGS+=-O2 -no-cpp-precomp -fbracket-depth=512
-HOST_CXXFLAGS+= -fbracket-depth=512
-.endif
 MAKE_PROGRAM?=	${MAKE}
 
 .for i in 3 2
Index: external/gpl3/gcc/dist/gcc/genattrtab.c
===================================================================
RCS file: /cvsroot/src/external/gpl3/gcc/dist/gcc/genattrtab.c,v
retrieving revision 1.1.1.4
diff -u -r1.1.1.4 genattrtab.c
--- external/gpl3/gcc/dist/gcc/genattrtab.c	2 Feb 2018 01:59:20 -0000	1.1.1.4
+++ external/gpl3/gcc/dist/gcc/genattrtab.c	15 Apr 2018 21:44:51 -0000
@@ -3416,7 +3416,10 @@
 
 /* Given a piece of RTX, print a C expression to test its truth value to OUTF.
    We use AND and IOR both for logical and bit-wise operations, so
-   interpret them as logical unless they are inside a comparison expression.  */
+   interpret them as logical unless they are inside a comparison expression.
+
+   An outermost pair of parentheses is emitted around this C expression unless
+   EMIT_PARENS is false.  */
 
 /* Interpret AND/IOR as bit-wise operations instead of logical.  */
 #define FLG_BITWISE		1
@@ -3432,16 +3435,16 @@
 #define FLG_OUTSIDE_AND		8
 
 static unsigned int
-write_test_expr (FILE *outf, rtx exp, unsigned int attrs_cached, int flags)
+write_test_expr (FILE *outf, rtx exp, unsigned int attrs_cached, int flags,
+		 bool emit_parens = true)
 {
   int comparison_operator = 0;
   RTX_CODE code;
   struct attr_desc *attr;
 
-  /* In order not to worry about operator precedence, surround our part of
-     the expression with parentheses.  */
+  if (emit_parens)
+    fprintf (outf, "(");
 
-  fprintf (outf, "(");
   code = GET_CODE (exp);
   switch (code)
     {
@@ -3575,8 +3578,18 @@
 	      || GET_CODE (XEXP (exp, 1)) == EQ_ATTR
 	      || (GET_CODE (XEXP (exp, 1)) == NOT
 		  && GET_CODE (XEXP (XEXP (exp, 1), 0)) == EQ_ATTR)))
-	attrs_cached
-	  = write_test_expr (outf, XEXP (exp, 1), attrs_cached, flags);
+	{
+	  bool need_parens = true;
+
+	  /* No need to emit parentheses around the right-hand operand if we are
+	     continuing a chain of && or || (or & or |).  */
+	  if (GET_CODE (XEXP (exp, 1)) == code)
+	    need_parens = false;
+
+	  attrs_cached
+	    = write_test_expr (outf, XEXP (exp, 1), attrs_cached, flags,
+			       need_parens);
+	}
       else
 	write_test_expr (outf, XEXP (exp, 1), attrs_cached,
 			 flags | comparison_operator);
@@ -3794,7 +3807,9 @@
 	     GET_RTX_NAME (code));
     }
 
-  fprintf (outf, ")");
+  if (emit_parens)
+    fprintf (outf, ")");
+
   return attrs_cached;
 }