re PR target/51340 (SH Target: Make -mfused-madd enabled by default)

	PR target/51340
	* config/sh/sh.c (sh_option_override): Set TARGET_FMAC if
	flag_unsafe_math_optimizations is set.
	* doc/invoke.texi (SH Options): Add -mno-fused-madd description.
	Update description of -mfused-madd.

	PR target/51340
	* gcc.target/sh/pr51340-1.c: New.
	* gcc.target/sh/pr51340-2.c: New.
	* gcc.target/sh/pr51340-3.c: New.

From-SVN: r187988

7 files changed, 71 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 26382f6..078ad6d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2012-05-29  Oleg Endo  <olegendo@gcc.gnu.org>
 
+	PR target/51340
+	* config/sh/sh.c (sh_option_override): Set TARGET_FMAC if
+	flag_unsafe_math_optimizations is set.
+	* doc/invoke.texi (SH Options): Add -mno-fused-madd description.
+	Update description of -mfused-madd.
+
+2012-05-29  Oleg Endo  <olegendo@gcc.gnu.org>
+
 	PR target/52941
 	* config/sh/predicates.md (atomic_arith_operand,
 	atomic_logical_operand): New predicates.
diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index 3c9a7e9..20e67c6 100644
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -876,6 +876,13 @@ sh_option_override (void)
 	align_functions = min_align;
     }
 
+  /* Enable fmac insn for "a * b + c" SFmode calculations when -ffast-math
+     is enabled and -mno-fused-madd is not specified by the user.
+     The fmac insn can't be enabled by default due to the implied
+     FMA semantics.   See also PR target/29100.  */
+  if (global_options_set.x_TARGET_FMAC == 0 && flag_unsafe_math_optimizations)
+    TARGET_FMAC = 1;
+
   if (sh_fixed_range_str)
     sh_fix_range (sh_fixed_range_str);
 
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index efab516..1102aff 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -885,8 +885,8 @@ See RS/6000 and PowerPC Options.
 -mdivsi3_libfunc=@var{name} -mfixed-range=@var{register-range} @gol
 -mindexed-addressing -mgettrcost=@var{number} -mpt-fixed @gol
 -maccumulate-outgoing-args -minvalid-symbols -msoft-atomic -mhard-atomic @gol
--mbranch-cost=@var{num} -mcbranchdi -mcmpeqdi -mfused-madd -mpretend-cmove @gol
--menable-tas}
+-mbranch-cost=@var{num} -mcbranchdi -mcmpeqdi -mfused-madd -mno-fused-madd @gol
+-mpretend-cmove -menable-tas}
 
 @emph{Solaris 2 Options}
 @gccoptlist{-mimpure-text  -mno-impure-text @gol
@@ -18250,11 +18250,17 @@ Emit the @code{cmpeqdi_t} instruction pattern even when @option{-mcbranchdi}
 is in effect.
 
 @item -mfused-madd
+@itemx -mno-fused-madd
 @opindex mfused-madd
-Allow the usage of the @code{fmac} instruction (floating-point
-multiply-accumulate) if the processor type supports it.  Enabling this
-option might generate code that produces different numeric floating-point
-results compared to strict IEEE 754 arithmetic.
+@opindex mno-fused-madd
+If the processor type supports it, setting @code{-mfused-madd} will allow the
+usage of the @code{fmac} instruction (floating-point multiply-accumulate) for
+regular calculations.  Enabling this option might generate faster code but also
+produce different numeric floating-point results compared to strict IEEE 754
+arithmetic.  @code{-mfused-madd} is enabled by default by option
+@option{-funsafe-math-optimizations}.  Setting @code{-mno-fused-madd} will
+disallow the usage of the @code{fmac} instruction for regular calculations
+even if @option{-funsafe-math-optimizations} is in effect.
 
 @item -mpretend-cmove
 @opindex mpretend-cmove
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 56bb5ab..ea8b09d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2012-05-29  Oleg Endo  <olegendo@gcc.gnu.org>
+
+	PR target/51340
+	* gcc.target/sh/pr51340-1.c: New.
+	* gcc.target/sh/pr51340-2.c: New.
+	* gcc.target/sh/pr51340-3.c: New.
+
 2012-05-29  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/53516
diff --git a/gcc/testsuite/gcc.target/sh/pr51340-1.c b/gcc/testsuite/gcc.target/sh/pr51340-1.c
new file mode 100644
index 0000000..337d502
--- /dev/null
+++ b/gcc/testsuite/gcc.target/sh/pr51340-1.c
@@ -0,0 +1,13 @@
+/* Check that the fmac insn is generated when -funsafe-math-optimizations
+   is specified.  */
+/* { dg-do compile { target "sh*-*-*" } } */
+/* { dg-options "-O1 -funsafe-math-optimizations" } */
+/* { dg-skip-if "" { "sh*-*-*" } { "-m1" "-m2" "-m4al" "*nofpu" "-m4-340*" "-m4-400*" "-m4-500*" "-m5*" } { "" } }  */
+/* { dg-final { scan-assembler "fmac" } } */
+
+float
+test_func (float a, float b, float c, float d, float e, float f)
+{
+  return a * b + c * d + e * f;
+}
+
diff --git a/gcc/testsuite/gcc.target/sh/pr51340-2.c b/gcc/testsuite/gcc.target/sh/pr51340-2.c
new file mode 100644
index 0000000..ef9622e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/sh/pr51340-2.c
@@ -0,0 +1,12 @@
+/* Check that the fmac insn is not generated when -mno-fused-madd is specified.  */
+/* { dg-do compile { target "sh*-*-*" } } */
+/* { dg-options "-O1 -funsafe-math-optimizations -mno-fused-madd" } */
+/* { dg-skip-if "" { "sh*-*-*" } { "-m1" "-m2" "-m4al" "*nofpu" "-m4-340*" "-m4-400*" "-m4-500*" "-m5*" } { "" } }  */
+/* { dg-final { scan-assembler-not "fmac" } } */
+
+float
+test_func (float a, float b, float c, float d, float e, float f)
+{
+  return a * b + c * d + e * f;
+}
+
diff --git a/gcc/testsuite/gcc.target/sh/pr51340-3.c b/gcc/testsuite/gcc.target/sh/pr51340-3.c
new file mode 100644
index 0000000..d641ae3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/sh/pr51340-3.c
@@ -0,0 +1,12 @@
+/* Check that the fmac insn is generated when -mfused-madd is specified.  */
+/* { dg-do compile { target "sh*-*-*" } } */
+/* { dg-options "-O1 -mfused-madd" } */
+/* { dg-skip-if "" { "sh*-*-*" } { "-m1" "-m2" "-m4al" "*nofpu" "-m4-340*" "-m4-400*" "-m4-500*" "-m5*" } { "" } }  */
+/* { dg-final { scan-assembler "fmac" } } */
+
+float
+test_func (float a, float b, float c, float d, float e, float f)
+{
+  return a * b + c * d + e * f;
+}
+