* common.opt (fcx-limited-range): Add SetByCombined flag.

	(ffinite-math-only, fmath-errno, frounding-math): Likewise.
	(fsignaling-nans, fsigned-zeros, ftrapping-math): Likewise.
	(fassociative-math, freciprocal-math): Likewise.
	(funsafe-math-optimizations): Likewise.
	* opth-gen.awk: Handle SetByCombined.
	* optc-gen.awk: Likewise.
	* opts.c (set_fast_math_flags): Don't override flag if set by
	frontend.
	(set_unsafe_math_optimizations_flags): Likewise.
	* doc/options.texi (Option properties): Document SetByCombined.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@169930 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 76 insertions, 26 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 81cac7d1a7c..e27a71fe59f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2011-02-08  Ian Lance Taylor  <iant@google.com>
+
+	* common.opt (fcx-limited-range): Add SetByCombined flag.
+	(ffinite-math-only, fmath-errno, frounding-math): Likewise.
+	(fsignaling-nans, fsigned-zeros, ftrapping-math): Likewise.
+	(fassociative-math, freciprocal-math): Likewise.
+	(funsafe-math-optimizations): Likewise.
+	* opth-gen.awk: Handle SetByCombined.
+	* optc-gen.awk: Likewise.
+	* opts.c (set_fast_math_flags): Don't override flag if set by
+	frontend.
+	(set_unsafe_math_optimizations_flags): Likewise.
+	* doc/options.texi (Option properties): Document SetByCombined.
+
 2011-02-08  Joseph Myers  <joseph@codesourcery.com>
 
 	* config.gcc (arc-*, alpha*-*-gnu*, arm*-*-netbsd*, arm-*-pe*,
diff --git a/gcc/common.opt b/gcc/common.opt
index aed8dd1a512..5485da92840 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1,6 +1,6 @@
 ; Options for the language- and target-independent parts of the compiler.
 
-; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
 ; Free Software Foundation, Inc.
 ;
 ; This file is part of GCC.
@@ -878,7 +878,7 @@ Common Ignore
 Does nothing.  Preserved for backward compatibility.
 
 fcx-limited-range
-Common Report Var(flag_cx_limited_range) Optimization
+Common Report Var(flag_cx_limited_range) Optimization SetByCombined
 Omit range reduction step when performing complex division
 
 fcx-fortran-rules
@@ -1024,7 +1024,7 @@ ffast-math
 Common
 
 ffinite-math-only
-Common Report Var(flag_finite_math_only) Optimization
+Common Report Var(flag_finite_math_only) Optimization SetByCombined
 Assume no NaNs or infinities are generated
 
 ffixed-
@@ -1340,7 +1340,7 @@ Common Report Var(flag_lto_report) Init(0) Optimization
 Report various link-time optimization statistics
 
 fmath-errno
-Common Report Var(flag_errno_math) Init(1) Optimization
+Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
 Set errno after built-in math functions
 
 fmax-errors=
@@ -1577,7 +1577,7 @@ Common Ignore
 Does nothing.  Preserved for backward compatibility.
 
 frounding-math
-Common Report Var(flag_rounding_math) Optimization
+Common Report Var(flag_rounding_math) Optimization SetByCombined
 Disable optimizations that assume default FP rounding behavior
 
 fsched-interblock
@@ -1706,11 +1706,11 @@ Common Report Var(flag_show_column) Init(1)
 Show column numbers in diagnostics, when available.  Default on
 
 fsignaling-nans
-Common Report Var(flag_signaling_nans) Optimization
+Common Report Var(flag_signaling_nans) Optimization SetByCombined
 Disable optimizations observable by IEEE signaling NaNs
 
 fsigned-zeros
-Common Report Var(flag_signed_zeros) Init(1) Optimization
+Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
 Disable floating point optimizations that ignore the IEEE signedness of zero
 
 fsingle-precision-constant
@@ -1827,7 +1827,7 @@ Perform superblock formation via tail duplication
 ; (user-visible) trap.  This is the case, for example, in nonstop
 ; IEEE 754 arithmetic.
 ftrapping-math
-Common Report Var(flag_trapping_math) Init(1) Optimization
+Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
 Assume floating-point operations can trap
 
 ftrapv
@@ -1978,12 +1978,12 @@ Common Report Var(flag_unsafe_loop_optimizations) Optimization
 Allow loop optimizations to assume that the loops behave in normal way
 
 fassociative-math
-Common Report Var(flag_associative_math)
+Common Report Var(flag_associative_math) SetByCombined
 Allow optimization for floating-point arithmetic which may change the
 result of the operation due to rounding.
 
 freciprocal-math
-Common Report Var(flag_reciprocal_math)
+Common Report Var(flag_reciprocal_math) SetByCombined
 Same as -fassociative-math for expressions which include division.
 
 ; Nonzero means that unsafe floating-point math optimizations are allowed
@@ -1991,7 +1991,7 @@ Same as -fassociative-math for expressions which include division.
 ; are allowed to assume that their arguments and results are "normal"
 ; (e.g., nonnegative for SQRT).
 funsafe-math-optimizations
-Common Report Var(flag_unsafe_math_optimizations) Optimization
+Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
 Allow math optimizations that may violate IEEE or ISO standards
 
 funswitch-loops
diff --git a/gcc/doc/options.texi b/gcc/doc/options.texi
index 1c8f5d9f134..e39d79e1c8f 100644
--- a/gcc/doc/options.texi
+++ b/gcc/doc/options.texi
@@ -1,4 +1,4 @@
-@c Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+@c Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
 @c Free Software Foundation, Inc.
 @c This is part of the GCC manual.
 @c For copying conditions, see the file gcc.texi.
@@ -436,4 +436,17 @@ the @option{--help} output.
 Build the @code{cl_target_option} structure to hold a copy of the
 option, add the functions @code{cl_target_option_save} and
 @code{cl_target_option_restore} to save and restore the options.
+
+@item SetByCombined
+The option may also be set by a combined option such as
+@option{-ffast-math}.  This causes the @code{gcc_options} struct to
+have a field @code{frontend_set_@var{name}}, where @code{@var{name}}
+is the name of the field holding the value of this option (without the
+leading @code{x_}).  This gives the front end a way to indicate that
+the value has been set explicitly and should not be changed by the
+combined option.  For example, some front ends use this to prevent
+@option{-ffast-math} and @option{-fno-fast-math} from changing the
+value of @option{-fmath-errno} for languages that do not use
+@code{errno}.
+
 @end table
diff --git a/gcc/optc-gen.awk b/gcc/optc-gen.awk
index 4aaa2a6041a..502b23bf6e0 100644
--- a/gcc/optc-gen.awk
+++ b/gcc/optc-gen.awk
@@ -1,4 +1,4 @@
-#  Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010
+#  Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011
 #  Free Software Foundation, Inc.
 #  Contributed by Kelley Cook, June 2004.
 #  Original code from Neil Booth, May 2003.
@@ -250,6 +250,10 @@ for (i = 0; i < n_opts; i++) {
 		print "#undef x_" name
 	}
 }
+for (i = 0; i < n_opts; i++) {
+	if (flag_set_p("SetByCombined", flags[i]))
+		print "  false, /* frontend_set_" var_name(flags[i]) " */"
+}
 print "};"
 print ""
 print "struct gcc_options global_options;"
diff --git a/gcc/opth-gen.awk b/gcc/opth-gen.awk
index db32121f914..c3f6c04ebfb 100644
--- a/gcc/opth-gen.awk
+++ b/gcc/opth-gen.awk
@@ -1,4 +1,4 @@
-#  Copyright (C) 2003,2004,2005,2006,2007,2008, 2010
+#  Copyright (C) 2003,2004,2005,2006,2007,2008, 2010, 2011
 #  Free Software Foundation, Inc.
 #  Contributed by Kelley Cook, June 2004.
 #  Original code from Neil Booth, May 2003.
@@ -193,6 +193,13 @@ for (i = 0; i < n_opts; i++) {
 		print "#endif"
 	}
 }
+for (i = 0; i < n_opts; i++) {
+	if (flag_set_p("SetByCombined", flags[i])) {
+		print "#ifndef GENERATOR_FILE"
+		print "  bool frontend_set_" var_name(flags[i]) ";"
+		print "#endif"
+	}
+}
 print "#ifndef GENERATOR_FILE"
 print "};"
 print "extern struct gcc_options global_options;"
diff --git a/gcc/opts.c b/gcc/opts.c
index 9a3fb133a31..8ca9c67bb8e 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1,5 +1,5 @@
 /* Command line option handling.
-   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Neil Booth.
 
@@ -1757,15 +1757,23 @@ set_Wstrict_aliasing (struct gcc_options *opts, int onoff)
 static void
 set_fast_math_flags (struct gcc_options *opts, int set)
 {
-  opts->x_flag_unsafe_math_optimizations = set;
-  set_unsafe_math_optimizations_flags (opts, set);
-  opts->x_flag_finite_math_only = set;
-  opts->x_flag_errno_math = !set;
+  if (!opts->frontend_set_flag_unsafe_math_optimizations)
+    {
+      opts->x_flag_unsafe_math_optimizations = set;
+      set_unsafe_math_optimizations_flags (opts, set);
+    }
+  if (!opts->frontend_set_flag_finite_math_only)
+    opts->x_flag_finite_math_only = set;
+  if (!opts->frontend_set_flag_errno_math)
+    opts->x_flag_errno_math = !set;
   if (set)
     {
-      opts->x_flag_signaling_nans = 0;
-      opts->x_flag_rounding_math = 0;
-      opts->x_flag_cx_limited_range = 1;
+      if (!opts->frontend_set_flag_signaling_nans)
+	opts->x_flag_signaling_nans = 0;
+      if (!opts->frontend_set_flag_rounding_math)
+	opts->x_flag_rounding_math = 0;
+      if (!opts->frontend_set_flag_cx_limited_range)
+	opts->x_flag_cx_limited_range = 1;
     }
 }
 
@@ -1774,10 +1782,14 @@ set_fast_math_flags (struct gcc_options *opts, int set)
 static void
 set_unsafe_math_optimizations_flags (struct gcc_options *opts, int set)
 {
-  opts->x_flag_trapping_math = !set;
-  opts->x_flag_signed_zeros = !set;
-  opts->x_flag_associative_math = set;
-  opts->x_flag_reciprocal_math = set;
+  if (!opts->frontend_set_flag_trapping_math)
+    opts->x_flag_trapping_math = !set;
+  if (!opts->frontend_set_flag_signed_zeros)
+    opts->x_flag_signed_zeros = !set;
+  if (!opts->frontend_set_flag_associative_math)
+    opts->x_flag_associative_math = set;
+  if (!opts->frontend_set_flag_reciprocal_math)
+    opts->x_flag_reciprocal_math = set;
 }
 
 /* Return true iff flags in OPTS are set as if -ffast-math.  */