re PR fortran/35259 (-fassociative-math not enabled by default; No option to…

re PR fortran/35259 (-fassociative-math not enabled by default;  No option to associate with PAREN_EXPRs)

2010-02-21  Tobias Burnus  <burnus@net-b.de>

        PR fortran/35259
        * doc/invoke.texi (-fassociative-math): Document that this
        option is automatically enabled for Fortran.

2010-02-21  Tobias Burnus  <burnus@net-b.de>

        PR fortran/35259
        * gfortran.h (gfc_option_t): New flag -fprotect-parens.
        * lang.opt: Ditto.
        * option.c (gfc_init_options,gfc_handle_option): Ditto.
        * trans-expr.c (gfc_conv_expr_op): Use the flag.
        * invoke.texi: Document new -fno-protect-parens flag.

2010-02-21  Tobias Burnus  <burnus@net-b.de>

        PR fortran/35259
        * gfortran.dg/reassoc_5.f90: New test.

From-SVN: r156937

gcc/ChangeLog

+2010-02-21  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/35259
+	* doc/invoke.texi (-fassociative-math): Document that this
+	option is automatically enabled for Fortran.
+
 2010-02-20  David S. Miller  <davem@davemloft.net>
 
 	* configure.ac: Test if linker and assembler properly support

gcc/doc/invoke.texi

@@ -7541,7 +7541,9 @@ thus cannot be used on a code which relies on rounding behavior like
 and thus may not be used when ordered comparisons are required.
 This option requires that both @option{-fno-signed-zeros} and
 @option{-fno-trapping-math} be in effect.  Moreover, it doesn't make
-much sense with @option{-frounding-math}.
+much sense with @option{-frounding-math}. For Fortran the option
+is automatically enabled when both @option{-fno-signed-zeros} and
+@option{-fno-trapping-math} are in effect.
 
 The default is @option{-fno-associative-math}.
 

gcc/fortran/ChangeLog

+2010-02-21  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/35259
+	* gfortran.h (gfc_option_t): New flag -fprotect-parens.
+	* lang.opt: Ditto.
+	* option.c (gfc_init_options,gfc_handle_option): Ditto.
+	* trans-expr.c (gfc_conv_expr_op): Use the flag.
+	* invoke.texi: Document new -fno-protect-parens flag.
+
 2010-02-20  Paul Thomas  <pault@gcc.gnu.org>
 
 	PR fortran/36932

gcc/fortran/gfortran.h

@@ -2150,6 +2150,7 @@ typedef struct
   char flag_init_character_value;
   int flag_align_commons;
   int flag_whole_file;
+  int flag_protect_parens;
 
   int fpe;
   int rtcheck;

gcc/fortran/invoke.texi

@@ -171,7 +171,8 @@ and warnings}.
 -fpack-derived  -frepack-arrays  -fshort-enums  -fexternal-blas @gol
 -fblas-matmul-limit=@var{n} -frecursive -finit-local-zero @gol
 -finit-integer=@var{n} -finit-real=@var{<zero|inf|-inf|nan|snan>} @gol
--finit-logical=@var{<true|false>} -finit-character=@var{n} -fno-align-commons}
+-finit-logical=@var{<true|false>} -finit-character=@var{n} @gol
+-fno-align-commons -fno-protect-parens}
 @end table
 
 @menu
@@ -1410,6 +1411,16 @@ consistent data types everywhere, this padding can cause trouble, and
 same form of this option should be used for all files that share a COMMON block.
 To avoid potential alignment issues in COMMON blocks, it is recommended to order
 objects from largests to smallest.
+
+@item -fno-protect-parens
+@opindex @code{fno-protect-parens}
+@cindex re-association of parenthesed expressions
+By default the parentheses in expression are honored for all optimization
+levels such that the compiler does not do any re-association. Using
+@option{-fno-protect-parens} allows the compiler to reorder REAL and
+COMPLEX expressions to produce faster code. Note that for the re-association
+optimization @option{-fno-signed-zeros} and @option{-fno-trapping-math}
+need to be in effect.
 @end table
 
 @xref{Code Gen Options,,Options for Code Generation Conventions,

gcc/fortran/lang.opt

@@ -324,6 +324,10 @@ fpreprocessed
 Fortran
 ; Documented in C
 
+fprotect-parens
+Fortran
+Protect parentheses in expressions
+
 frange-check
 Fortran
 Enable range checking during compilation

gcc/fortran/options.c

@@ -125,6 +125,7 @@ gfc_init_options (unsigned int argc, const char **argv)
   gfc_option.flag_init_character = GFC_INIT_CHARACTER_OFF;
   gfc_option.flag_init_character_value = (char)0;
   gfc_option.flag_align_commons = 1;
+  gfc_option.flag_protect_parens = 1;
   
   gfc_option.fpe = 0;
   gfc_option.rtcheck = 0;
@@ -921,6 +922,10 @@ gfc_handle_option (size_t scode, const char *arg, int value)
       gfc_option.flag_align_commons = value;
       break;
 
+    case OPT_fprotect_parens:
+      gfc_option.flag_protect_parens = value;
+      break;
+
     case OPT_fcheck_:
       gfc_handle_runtime_check_option (arg);
       break;

gcc/fortran/trans-expr.c

@@ -1222,8 +1222,9 @@ gfc_conv_expr_op (gfc_se * se, gfc_expr * expr)
   switch (expr->value.op.op)
     {
     case INTRINSIC_PARENTHESES:
-      if (expr->ts.type == BT_REAL
-	  || expr->ts.type == BT_COMPLEX)
+      if ((expr->ts.type == BT_REAL
+	   || expr->ts.type == BT_COMPLEX)
+	  && gfc_option.flag_protect_parens)
 	{
 	  gfc_conv_unary_op (PAREN_EXPR, se, expr);
 	  gcc_assert (FLOAT_TYPE_P (TREE_TYPE (se->expr)));

gcc/testsuite/ChangeLog

+2010-02-21  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/35259
+	* gfortran.dg/reassoc_5.f90: New test.
+
 2010-02-20  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/43067

gcc/testsuite/gfortran.dg/reassoc_5.f90

+! { dg-do compile }
+! { dg-options "-O3 -ffast-math -fdump-tree-optimized -fno-protect-parens" }
+!
+! PR fortran/35259
+! Test for -fno-protect-parens
+!
+function test(b)
+  real a
+  a = (b + 5.) - 5.
+  test = a
+end
+
+! Test copied from reassoc_1.f90 which checked for -fprotect-parens (default),
+! and thus for the occurance of "5 - 5".
+!
+! We need an explicit +5 and -5, and an intermediate ((bla)) expression
+! (the reassoc barrier).  Make use of "." matching lineends.
+! { dg-final { scan-tree-dump-times "\\\+ 5.*\\\)\\\).* - 5" 0 "optimized" } }
+! { dg-final { cleanup-tree-dump "optimized" } }