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RE: [patch mips/gcc] add build-time and runtime options to disable or set madd.fmt type


Matthew Fortune <matthew.fortune@imgtec.com> writes:
> I've rewritten/simplified this patch as it provides far too much control
> to end users who will undoubtedly shoot themselves in the foot so to
> speak. The option I intend to support is simply --with-madd4 --without-madd4
> and -mmadd4 -mno-madd4. This is a simple enable/disable on top of
> architecture checks to use/not use the madd4 family of instructions.
> 
> We have to keep each of these unusual features simple so that we can somehow
> reason about them in the future.
> 

Here is the tested patch.  Configure time default set/not set tested and testsuite
fixes in place to deal with the fallout from running with the madd4 instructions
disabled.  Tests done with an o32 config on mips64el-linux-gnu.  If there is any
other fallout from other test configurations I'll catch those as I try to get the
rest of the testsuite issues resolved before release.

Catherine, any issues to raise on this new option?

Thanks,
Matthew

gcc/

	* config.gcc (supported_defaults): Add madd4.
	(with_madd4): Add validation.
	(all_defaults): Add madd4.
	* config/mips/mips.opt (mmadd4): New option.
	* gcc/config/mips/mips.h (OPTION_DEFAULT_SPECS): Add a default for
	mmadd4.
	(TARGET_CPU_CPP_BUILTINS): Add builtin_define for
	__mips_no_madd4.
	(ISA_HAS_UNFUSED_MADD4): Gate with mips_madd4.
	(ISA_HAS_FUSED_MADD4): Likewise.
	* gcc/doc/invoke.texi (-mmadd4): Document the new option.
	* doc/install.texi (--with-madd4): Document the new option.

gcc/testsuite/

	* gcc.target/mips/madd4-1.c: New file.
	* gcc.target/mips/madd4-2.c: Likewise.
	* gcc.target/mips/mips.exp (mips_option_groups): Add ghost option
	HAS_MADD4.
	(mips_option_groups): Add -m[no-]madd4.
	(mips-dg-init): Detect default -mno-madd4.
	(mips-dg-options): Handle HAS_MADD4 arch upgrade/downgrade.
	* gcc.target/mips/mips-ps-type.c: Add -mmadd4 test option.
	* gcc.target/mips/mips-ps-type-2.c: Likewise.
	* gcc.target/mips/nmadd-1.c: Likewise.
	* gcc.target/mips/nmadd-2.c: Likewise.
	* gcc.target/mips/nmadd-3.c: Likewise.
---
 gcc/ChangeLog                                  | 16 ++++++++++++++++
 gcc/config.gcc                                 | 19 +++++++++++++++++--
 gcc/config/mips/mips.h                         | 12 +++++++++---
 gcc/config/mips/mips.opt                       |  4 ++++
 gcc/doc/install.texi                           | 14 ++++++++++++++
 gcc/doc/invoke.texi                            |  8 +++++++-
 gcc/testsuite/ChangeLog                        | 15 +++++++++++++++
 gcc/testsuite/gcc.target/mips/madd4-1.c        | 14 ++++++++++++++
 gcc/testsuite/gcc.target/mips/madd4-2.c        | 14 ++++++++++++++
 gcc/testsuite/gcc.target/mips/mips-ps-type-2.c |  2 +-
 gcc/testsuite/gcc.target/mips/mips-ps-type.c   |  2 +-
 gcc/testsuite/gcc.target/mips/mips.exp         | 12 +++++++++++-
 gcc/testsuite/gcc.target/mips/nmadd-1.c        |  2 +-
 gcc/testsuite/gcc.target/mips/nmadd-2.c        |  2 +-
 gcc/testsuite/gcc.target/mips/nmadd-3.c        |  2 +-
 15 files changed, 126 insertions(+), 12 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/mips/madd4-1.c
 create mode 100644 gcc/testsuite/gcc.target/mips/madd4-2.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e53f9e1..7496071 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2017-01-19  Matthew Fortune  <matthew.fortune@imgtec.com>
+	    Yunqiang Su  <yunqiang.su@imgtec.com>
+
+	* config.gcc (supported_defaults): Add madd4.
+	(with_madd4): Add validation.
+	(all_defaults): Add madd4.
+	* config/mips/mips.opt (mmadd4): New option.
+	* gcc/config/mips/mips.h (OPTION_DEFAULT_SPECS): Add a default for
+	mmadd4.
+	(TARGET_CPU_CPP_BUILTINS): Add builtin_define for
+	__mips_no_madd4.
+	(ISA_HAS_UNFUSED_MADD4): Gate with mips_madd4.
+	(ISA_HAS_FUSED_MADD4): Likewise.
+	* gcc/doc/invoke.texi (-mmadd4): Document the new option.
+	* doc/install.texi (--with-madd4): Document the new option.
+
 2017-01-19  Chenghua Xu  <paul.hua.gm@gmail.com>
 
 	* config/mips/mips.h (ISA_HAS_FUSED_MADD4): Enable for
diff --git a/gcc/config.gcc b/gcc/config.gcc
index dd8c08c..9e67d36 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -3940,7 +3940,7 @@ case "${target}" in
 		;;
 
 	mips*-*-*)
-		supported_defaults="abi arch arch_32 arch_64 float fpu nan fp_32 odd_spreg_32 tune tune_32 tune_64 divide llsc mips-plt synci lxc1-sxc1"
+		supported_defaults="abi arch arch_32 arch_64 float fpu nan fp_32 odd_spreg_32 tune tune_32 tune_64 divide llsc mips-plt synci lxc1-sxc1 madd4"
 
 		case ${with_float} in
 		"" | soft | hard)
@@ -4078,6 +4078,21 @@ case "${target}" in
 			exit 1
 			;;
 		esac
+
+		case ${with_madd4} in
+		yes)
+			with_madd4=madd4
+			;;
+		no)
+			with_madd4=no-madd4
+			;;
+		"")
+			;;
+		*)
+			echo "Unknown madd4 type used in --with-madd4" 1>&2
+			exit 1
+			;;
+		esac
 		;;
 
 	nds32*-*-*)
@@ -4511,7 +4526,7 @@ case ${target} in
 esac
 
 t=
-all_defaults="abi cpu cpu_32 cpu_64 arch arch_32 arch_64 tune tune_32 tune_64 schedule float mode fpu nan fp_32 odd_spreg_32 divide llsc mips-plt synci tls lxc1-sxc1"
+all_defaults="abi cpu cpu_32 cpu_64 arch arch_32 arch_64 tune tune_32 tune_64 schedule float mode fpu nan fp_32 odd_spreg_32 divide llsc mips-plt synci tls lxc1-sxc1 madd4"
 for option in $all_defaults
 do
 	eval "val=\$with_"`echo $option | sed s/-/_/g`
diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 81032c9..23e1672 100644
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -639,6 +639,8 @@ struct mips_cpu_info {
 	builtin_define ("__GCC_HAVE_BUILTIN_MIPS_CACHE");		\
       if (!ISA_HAS_LXC1_SXC1)						\
 	builtin_define ("__mips_no_lxc1_sxc1");				\
+      if (!ISA_HAS_UNFUSED_MADD4 && !ISA_HAS_FUSED_MADD4)		\
+	builtin_define ("__mips_no_madd4");				\
     }									\
   while (0)
 
@@ -869,7 +871,8 @@ struct mips_cpu_info {
   {"llsc", "%{!mllsc:%{!mno-llsc:-m%(VALUE)}}" }, \
   {"mips-plt", "%{!mplt:%{!mno-plt:-m%(VALUE)}}" }, \
   {"synci", "%{!msynci:%{!mno-synci:-m%(VALUE)}}" },			\
-  {"lxc1-sxc1", "%{!mlxc1-sxc1:%{!mno-lxc1-sxc1:-m%(VALUE)}}" } \
+  {"lxc1-sxc1", "%{!mlxc1-sxc1:%{!mno-lxc1-sxc1:-m%(VALUE)}}" }, \
+  {"madd4", "%{!mmadd4:%{!mno-madd4:-m%(VALUE)}}" } \
 
 /* A spec that infers the:
    -mnan=2008 setting from a -mips argument,
@@ -1066,11 +1069,14 @@ struct mips_cpu_info {
 
 /* ISA has 4 operand fused madd instructions of the form
    'd = [+-] (a * b [+-] c)'.  */
-#define ISA_HAS_FUSED_MADD4	(TARGET_MIPS8000 || TARGET_LOONGSON_3A)
+#define ISA_HAS_FUSED_MADD4	(mips_madd4				\
+				 && (TARGET_MIPS8000			\
+				     || TARGET_LOONGSON_3A))
 
 /* ISA has 4 operand unfused madd instructions of the form
    'd = [+-] (a * b [+-] c)'.  */
-#define ISA_HAS_UNFUSED_MADD4	(ISA_HAS_FP4				\
+#define ISA_HAS_UNFUSED_MADD4	(mips_madd4				\
+				 && ISA_HAS_FP4				\
 				 && !TARGET_MIPS8000			\
 				 && !TARGET_LOONGSON_3A)
 
diff --git a/gcc/config/mips/mips.opt b/gcc/config/mips/mips.opt
index 75ebafd..7c4b607 100644
--- a/gcc/config/mips/mips.opt
+++ b/gcc/config/mips/mips.opt
@@ -392,6 +392,10 @@ mlxc1-sxc1
 Target Report Var(mips_lxc1_sxc1) Init(1)
 Use lwxc1/swxc1/ldxc1/sdxc1 instructions where applicable.
 
+mmadd4
+Target Report Var(mips_madd4) Init(1)
+Use 4-operand madd.s/madd.d and related instructions where applicable.
+
 mtune=
 Target RejectNegative Joined Var(mips_tune_option) ToLower Enum(mips_arch_opt_value)
 -mtune=PROCESSOR	Optimize the output for PROCESSOR.
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 712b82a..e2ff308 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1394,6 +1394,20 @@ in @code{lwxc1} type instructions.  This assumption holds true in a
 pure 32-bit environment and can hold true in a 64-bit environment if
 the address space is accurately set to be 32-bit for o32 and n32.
 
+@item --with-madd4
+On MIPS targets, make @option{-mmadd4} the default when no
+@option{-mno-madd4} option is passed.  This is the default.
+
+@item --without-madd4
+On MIPS targets, make @option{-mno-madd4} the default when no
+@option{-mmadd4} option is passed.  The @code{madd4} instruction
+family can be problematic when targetting a combination of cores that
+implement these instructions differently.  There are two known cores
+that implemeent these as fused operations instead of unfused (where
+unfused is normally expected).  Disabling these instructions is the
+only way to ensure compatible code is generated; this will incur
+a performance penalty.
+
 @item --with-mips-plt
 On MIPS targets, make use of copy relocations and PLTs.
 These features are extensions to the traditional
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 2d2976b..c04f415 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -909,7 +909,7 @@ Objective-C and Objective-C++ Dialects}.
 -mcompact-branches=@var{policy} @gol
 -mfp-exceptions  -mno-fp-exceptions @gol
 -mvr4130-align  -mno-vr4130-align  -msynci  -mno-synci @gol
--mlxc1-sxc1 -mno-lxc1-sxc1 @gol
+-mlxc1-sxc1 -mno-lxc1-sxc1 -mmadd4 -mno-madd4 @gol
 -mrelax-pic-calls  -mno-relax-pic-calls  -mmcount-ra-address @gol
 -mframe-header-opt  -mno-frame-header-opt}
 
@@ -19939,6 +19939,12 @@ This optimization is off by default at all optimization levels.
 When applicable, enable (disable) the generation of @code{lwxc1},
 @code{swxc1}, @code{ldxc1}, @code{sdxc1} instructions.  Enabled by default.
 
+@item -mmadd4
+@itemx -mno-madd4
+@opindex mmadd4
+When applicable, enable (disable) the generation of 4-operand @code{madd.s},
+@code{madd.d} and related instructions.  Enabled by default.
+
 @end table
 
 @node MMIX Options
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0ba8f93..34f15bb 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,20 @@
 2017-01-19  Matthew Fortune  <matthew.fortune@imgtec.com>
 
+	* gcc.target/mips/madd4-1.c: New file.
+	* gcc.target/mips/madd4-2.c: Likewise.
+	* gcc.target/mips/mips.exp (mips_option_groups): Add ghost option
+	HAS_MADD4.
+	(mips_option_groups): Add -m[no-]madd4.
+	(mips-dg-init): Detect default -mno-madd4.
+	(mips-dg-options): Handle HAS_MADD4 arch upgrade/downgrade.
+	* gcc.target/mips/mips-ps-type.c: Add -mmadd4 test option.
+	* gcc.target/mips/mips-ps-type-2.c: Likewise.
+	* gcc.target/mips/nmadd-1.c: Likewise.
+	* gcc.target/mips/nmadd-2.c: Likewise.
+	* gcc.target/mips/nmadd-3.c: Likewise.
+
+2017-01-19  Matthew Fortune  <matthew.fortune@imgtec.com>
+
 	PR target/78176
 	* gcc.target/mips/lxc1-sxc1-1.c: New file.
 	* gcc.target/mips/lxc1-sxc1-2.c: Likewise.
diff --git a/gcc/testsuite/gcc.target/mips/madd4-1.c b/gcc/testsuite/gcc.target/mips/madd4-1.c
new file mode 100644
index 0000000..d0dee36
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/madd4-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-ffast-math -mno-madd4 (HAS_MADD4) -mhard-float" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+/* { dg-final { scan-assembler-not "\tmadd.s\t" } } */
+
+#ifndef __mips_no_madd4
+#error missing definition of __mips_no_madd4
+#endif
+
+NOMIPS16 float
+madd4 (float f, float g, float h)
+{
+  return (f * g) + h;
+}
diff --git a/gcc/testsuite/gcc.target/mips/madd4-2.c b/gcc/testsuite/gcc.target/mips/madd4-2.c
new file mode 100644
index 0000000..eb83023
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/madd4-2.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-ffast-math -mmadd4 (HAS_MADD4) -mhard-float" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+/* { dg-final { scan-assembler "\tmadd.s\t" } } */
+
+#ifdef __mips_no_madd4
+#error unexpected definition of __mips_no_madd4
+#endif
+
+NOMIPS16 float
+madd4 (float f, float g, float h)
+{
+  return (f * g) + h;
+}
diff --git a/gcc/testsuite/gcc.target/mips/mips-ps-type-2.c b/gcc/testsuite/gcc.target/mips/mips-ps-type-2.c
index 6aba815..fecc35b 100644
--- a/gcc/testsuite/gcc.target/mips/mips-ps-type-2.c
+++ b/gcc/testsuite/gcc.target/mips/mips-ps-type-2.c
@@ -1,7 +1,7 @@
 /* Test v2sf calculations.  The nmadd and nmsub patterns need
    -ffinite-math-only.  */
 /* { dg-do compile } */
-/* { dg-options "(HAS_MADDPS) -mgp32 -mpaired-single -ffinite-math-only forbid_cpu=octeon.*" } */
+/* { dg-options "(HAS_MADDPS) -mmadd4 -mgp32 -mpaired-single -ffinite-math-only forbid_cpu=octeon.*" } */
 /* { dg-skip-if "nmadd and nmsub need combine" { *-*-* } { "-O0" } { "" } } */
 /* { dg-final { scan-assembler "\tcvt.ps.s\t" } } */
 /* { dg-final { scan-assembler "\tmov.ps\t" } } */
diff --git a/gcc/testsuite/gcc.target/mips/mips-ps-type.c b/gcc/testsuite/gcc.target/mips/mips-ps-type.c
index 454ffc3..d74d4b5 100644
--- a/gcc/testsuite/gcc.target/mips/mips-ps-type.c
+++ b/gcc/testsuite/gcc.target/mips/mips-ps-type.c
@@ -1,7 +1,7 @@
 /* Test v2sf calculations.  The nmadd and nmsub patterns need
    -ffinite-math-only.  */
 /* { dg-do compile } */ 
-/* { dg-options "-mpaired-single -mgp64 -ffinite-math-only forbid_cpu=octeon.*" } */
+/* { dg-options "-mpaired-single -mmadd4 -mgp64 -ffinite-math-only forbid_cpu=octeon.*" } */
 /* { dg-skip-if "nmadd and nmsub need combine" { *-*-* } { "-O0" } { "" } } */
 /* { dg-final { scan-assembler "\tcvt.ps.s\t" } } */
 /* { dg-final { scan-assembler "\tmov.ps\t" } } */
diff --git a/gcc/testsuite/gcc.target/mips/mips.exp b/gcc/testsuite/gcc.target/mips/mips.exp
index 5296a15f..78fbba0 100644
--- a/gcc/testsuite/gcc.target/mips/mips.exp
+++ b/gcc/testsuite/gcc.target/mips/mips.exp
@@ -256,6 +256,7 @@ set mips_option_groups {
     ldc "HAS_LDC"
     movn "HAS_MOVN"
     madd "HAS_MADD"
+    madd4_ghost "HAS_MADD4"
     maddps "HAS_MADDPS"
     lsa "(|!)HAS_LSA"
     lxc1 "HAS_LXC1"
@@ -284,6 +285,7 @@ foreach option {
     local-sdata
     long-calls
     lxc1-sxc1
+    madd4
     paired-single
     plt
     shared
@@ -863,6 +865,12 @@ proc mips-dg-init {} {
 	    "-mlxc1-sxc1"
 	    #endif
 
+	    #ifdef __mips_no_madd4
+	    "-mno-madd4"
+	    #else
+	    "-mmadd4"
+	    #endif
+
 	    #ifdef __mips_synci
 	    "-msynci",
 	    #else
@@ -1182,6 +1190,7 @@ proc mips-dg-options { args } {
 	#
 	} elseif { $isa < 4
 		   && ([mips_have_test_option_p options "HAS_LXC1"]
+		       || [mips_have_test_option_p options "HAS_MADD4"]
 		       || [mips_have_test_option_p options "HAS_MOVN"]) } {
 	    mips_make_test_option options "-mips4"
         # We need MIPS III or higher for:
@@ -1224,8 +1233,9 @@ proc mips-dg-options { args } {
 		       || [mips_have_test_option_p options "-mfix-r10000"]
 		       || [mips_have_test_option_p options "NOT_HAS_DMUL"]
 		       || [mips_have_test_option_p options "HAS_LXC1"]
-		       || [mips_have_test_option_p options "HAS_MOVN"]
 		       || [mips_have_test_option_p options "HAS_MADD"]
+		       || [mips_have_test_option_p options "HAS_MADD4"]
+		       || [mips_have_test_option_p options "HAS_MOVN"]
 		       || [mips_have_test_option_p options "-mpaired-single"]
 		       || [mips_have_test_option_p options "-mnan=legacy"]
 		       || [mips_have_test_option_p options "-mabs=legacy"]
diff --git a/gcc/testsuite/gcc.target/mips/nmadd-1.c b/gcc/testsuite/gcc.target/mips/nmadd-1.c
index 00be144..746fbbb 100644
--- a/gcc/testsuite/gcc.target/mips/nmadd-1.c
+++ b/gcc/testsuite/gcc.target/mips/nmadd-1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-ffast-math isa=4 -mhard-float" } */
+/* { dg-options "-ffast-math -mmadd4 isa=4 -mhard-float" } */
 /* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
 /* { dg-final { scan-assembler "\tnmadd.s\t" } } */
 /* { dg-final { scan-assembler "\tnmadd.d\t" } } */
diff --git a/gcc/testsuite/gcc.target/mips/nmadd-2.c b/gcc/testsuite/gcc.target/mips/nmadd-2.c
index a271f33..4c8dd65 100644
--- a/gcc/testsuite/gcc.target/mips/nmadd-2.c
+++ b/gcc/testsuite/gcc.target/mips/nmadd-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-fno-fast-math -ffinite-math-only isa=4 -mhard-float" } */
+/* { dg-options "-fno-fast-math -ffinite-math-only -mmadd4 isa=4 -mhard-float" } */
 /* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
 /* { dg-final { scan-assembler "\tnmadd.s\t" } } */
 /* { dg-final { scan-assembler "\tnmadd.d\t" } } */
diff --git a/gcc/testsuite/gcc.target/mips/nmadd-3.c b/gcc/testsuite/gcc.target/mips/nmadd-3.c
index 85de518..b55de96 100644
--- a/gcc/testsuite/gcc.target/mips/nmadd-3.c
+++ b/gcc/testsuite/gcc.target/mips/nmadd-3.c
@@ -1,7 +1,7 @@
 /* The same code as nmadd-2.c, but compiled with -fno-finite-math-only.
    We can't use nmadd and nmsub in that case.  */
 /* { dg-do compile } */
-/* { dg-options "-fno-fast-math -fno-finite-math-only isa=4 -mhard-float" } */
+/* { dg-options "-fno-fast-math -fno-finite-math-only -mmadd4 isa=4 -mhard-float" } */
 /* { dg-final { scan-assembler-not "\tnmadd" } } */
 /* { dg-final { scan-assembler-not "\tnmsub" } } */
 
-- 
2.2.1


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