PR tree-optimization/34036

	* opts.c (set_fast_math_flags): Do not set flags in common
	with set_unsafe_math_optimizations_flags, invoke it directly.
	(set_unsafe_math_optimizations_flags): Unset flag_trapping_math
	and flag_signed_zeros.
	* toplev.c (process_options): Force flag_associative_math to 0 and
	warn, if it is set and either flag_trapping_math or flag_signed_zeros
	is set too.
	* doc/invoke.texi (Optimize Options): Document the new behavior
	of -funsafe-math-optimizations, that -fassociative-math requires
	both -fno-signed-zeros and -fno-trapping-math and make it clear
	that -fno-trapping-math requires -fno-signaling-nans.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130286 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cf958d1..b3e98e1 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,18 @@
+2007-11-19  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+       PR tree-optimization/34036
+       * opts.c (set_fast_math_flags): Do not set flags in common
+       with set_unsafe_math_optimizations_flags, invoke it directly.
+       (set_unsafe_math_optimizations_flags): Unset flag_trapping_math
+       and flag_signed_zeros.
+       * toplev.c (process_options): Force flag_associative_math to 0 and
+       warn, if it is set and either flag_trapping_math or flag_signed_zeros
+       is set too.
+       * doc/invoke.texi (Optimize Options): Document the new behavior
+       of -funsafe-math-optimizations, that -fassociative-math requires
+       both -fno-signed-zeros and -fno-trapping-math and make it clear
+       that -fno-trapping-math requires -fno-signaling-nans.
+
 2007-11-18  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/34132

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 4679ded..adf50ad 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -6274,7 +6274,8 @@ it can result in incorrect output for programs which depend on
 an exact implementation of IEEE or ISO rules/specifications for
 math functions. It may, however, yield faster code for programs
 that do not require the guarantees of these specifications.
-Enables @option{-freciprocal-math} and @option{-fassociative-math}.
+Enables @option{-fno-signed-zeros}, @option{-fno-trapping-math},
+@option{-fassociative-math} and @option{-freciprocal-math}.
 
 The default is @option{-fno-unsafe-math-optimizations}.
 
@@ -6288,8 +6289,9 @@ well as ignore NaNs and inhibit or create underflow or overflow (and
 thus cannot be used on a code which relies on rounding behavior like
 @code{(x + 2**52) - 2**52)}.  May also reorder floating-point comparisons
 and thus may not be used when ordered comparisons are required.
-This flag doesn't make much sense without @option{-fno-signed-zeros}
-or @option{-fno-trapping-math} or with @option{-frounding-math}.
+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}.
 
 The default is @option{-fno-associative-math}.
 
@@ -6331,9 +6333,9 @@ The default is @option{-fsigned-zeros}.
 @opindex fno-trapping-math
 Compile code assuming that floating-point operations cannot generate
 user-visible traps.  These traps include division by zero, overflow,
-underflow, inexact result and invalid operation.  This option implies
-@option{-fno-signaling-nans}.  Setting this option may allow faster
-code if one relies on ``non-stop'' IEEE arithmetic, for example.
+underflow, inexact result and invalid operation.  This option requires
+that @option{-fno-signaling-nans} be in effect.  Setting this option may
+allow faster code if one relies on ``non-stop'' IEEE arithmetic, for example.
 
 This option should never be turned on by any @option{-O} option since
 it can result in incorrect output for programs which depend on

diff --git a/gcc/opts.c b/gcc/opts.c
index 90c9139..8be098f 100644 (file)
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1868,12 +1868,9 @@ set_Wstrict_aliasing (int onoff)
 void
 set_fast_math_flags (int set)
 {
-  flag_trapping_math = !set;
   flag_unsafe_math_optimizations = set;
-  flag_associative_math = set;
-  flag_reciprocal_math = set;
+  set_unsafe_math_optimizations_flags (set);
   flag_finite_math_only = set;
-  flag_signed_zeros = !set;
   flag_errno_math = !set;
   if (set)
     {
@@ -1888,8 +1885,10 @@ set_fast_math_flags (int set)
 void
 set_unsafe_math_optimizations_flags (int set)
 {
-  flag_reciprocal_math = set;
+  flag_trapping_math = !set;
+  flag_signed_zeros = !set;
   flag_associative_math = set;
+  flag_reciprocal_math = set;
 }
 
 /* Return true iff flags are set as if -ffast-math.  */

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 12eb548..bf7d440 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2007-11-19  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+       * gcc.dg/pr33007.c: Expect new warning.
+       * gcc.dg/tree-ssa/recip-5.c: Likewise.
+       * g++.dg/opt/pr34036.C: New test.
+
 2007-11-18  Jakub Jelinek  <jakub@redhat.com>
 
        PR c++/30988

diff --git a/gcc/testsuite/g++.dg/opt/pr34036.C b/gcc/testsuite/g++.dg/opt/pr34036.C
new file mode 100644 (file)
index 0000000..ecf6cf7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr34036.C
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fnon-call-exceptions -ffast-math -fsignaling-nans" } */
+/* { dg-warning "-fassociative-math disabled" "" { target *-*-* } 1 } */
+
+template <class T>
+class ggStaticArray {
+public:
+  ~ggStaticArray();
+};
+
+template <class T>
+class ggGrid {
+public:
+  ggGrid() : grid() { }
+  ggStaticArray<T> grid;
+};
+
+class mrGrid {
+public:
+  mrGrid(void);
+protected:
+  ggGrid<int*> grid;
+  double multiplier;
+};
+
+mrGrid::mrGrid(void)
+{
+  double xMeasure, yMeasure, zMeasure;
+  double cellDimension;
+
+  cellDimension = multiplier * (xMeasure * yMeasure * zMeasure);
+}

diff --git a/gcc/testsuite/gcc.dg/pr33007.c b/gcc/testsuite/gcc.dg/pr33007.c
index b1fc428..26b22fd 100644 (file)
--- a/gcc/testsuite/gcc.dg/pr33007.c
+++ b/gcc/testsuite/gcc.dg/pr33007.c
@@ -1,5 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-O -ffast-math -ftrapping-math" } */
+/* { dg-warning "-fassociative-math disabled" "" { target *-*-* } 1 } */
 
 long
 foo (int i)

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/recip-5.c b/gcc/testsuite/gcc.dg/tree-ssa/recip-5.c
index bcbd183..aafa98f 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/recip-5.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/recip-5.c
@@ -1,5 +1,6 @@
 /* { dg-options "-O1 -funsafe-math-optimizations -ftrapping-math -fdump-tree-recip -fdump-tree-optimized" } */
 /* { dg-do compile } */
+/* { dg-warning "-fassociative-math disabled" "" { target *-*-* } 1 } */
 
 /* Test the reciprocal optimizations together with trapping math.  */
 

diff --git a/gcc/toplev.c b/gcc/toplev.c
index f7f887a..c1520a3 100644 (file)
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -1988,6 +1988,13 @@ process_options (void)
   if (flag_signaling_nans)
     flag_trapping_math = 1;
 
+  /* We cannot reassociate if we want traps or signed zeros.  */
+  if (flag_associative_math && (flag_trapping_math || flag_signed_zeros))
+    {
+      warning (0, "-fassociative-math disabled; other options take precedence");
+      flag_associative_math = 0;
+    }
+
   /* With -fcx-limited-range, we do cheap and quick complex arithmetic.  */
   if (flag_cx_limited_range)
     flag_complex_method = 0;