Patchwork [mips] Patch to control the use of integer madd/msub instructions

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Submitter Steve Ellcey
Date March 25, 2013, 10:50 p.m.
Message ID <1364251806.18314.133.camel@ubuntu-sellcey>
Download mbox | patch
Permalink /patch/231007/
State New
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Comments

Steve Ellcey - March 25, 2013, 10:50 p.m.
On Mon, 2013-03-25 at 21:50 +0000, Richard Sandiford wrote:

> That's trivial enough not to need a retest, but please post the
> invoke.texi patch.
> 
> Thanks,
> Richard

Ah, yes I always forget the documentation.  Here is the complete patch.
It has the invoke.texi change at the bottom and I fixed up the comments
in mips.h.

Steve Ellcey
sellcey@imgtec.com



2013-03-25  Steve Ellcey  <sellcey@mips.com>

	* config/mips/mmips-cpus.def (74kc, 74kf2_1, 74kf, 74kf, 74kf1_1,
	74kfx, 74kx, 74kf3_2): Add PTF_AVOID_IMADD.
	* config/mips/mips.c (mips_option_override): Set IMADD default.
	* config/mips/mips.h (PTF_AVOID_IMADD): New.
	(ISA_HAS_MADD_MSUB): Remove MIPS16 check.
	(GENERATE_MADD_MSUB): Remove TUNE_74K check, add MIPS16 check.
	* config/mips/mips.md (mimadd): New flag for integer madd/msub.
	* doc/invoke.texi (-mimadd/-mno-imadd): New.
Richard Sandiford - March 25, 2013, 10:59 p.m.
Steve Ellcey <sellcey@imgtec.com> writes:
> 	* config/mips/mmips-cpus.def (74kc, 74kf2_1, 74kf, 74kf, 74kf1_1,
> 	74kfx, 74kx, 74kf3_2): Add PTF_AVOID_IMADD.
> 	* config/mips/mips.c (mips_option_override): Set IMADD default.
> 	* config/mips/mips.h (PTF_AVOID_IMADD): New.
> 	(ISA_HAS_MADD_MSUB): Remove MIPS16 check.
> 	(GENERATE_MADD_MSUB): Remove TUNE_74K check, add MIPS16 check.
> 	* config/mips/mips.md (mimadd): New flag for integer madd/msub.
> 	* doc/invoke.texi (-mimadd/-mno-imadd): New.

OK, thanks.

Richard

Patch

diff --git a/gcc/config/mips/mips-cpus.def b/gcc/config/mips/mips-cpus.def
index 1cc1999..9e5fd16 100644
--- a/gcc/config/mips/mips-cpus.def
+++ b/gcc/config/mips/mips-cpus.def
@@ -121,13 +121,13 @@  MIPS_CPU ("34kfx", PROCESSOR_24KF1_1, 33, 0)
 MIPS_CPU ("34kx", PROCESSOR_24KF1_1, 33, 0)
 MIPS_CPU ("34kn", PROCESSOR_24KC, 33, 0)  /* 34K with MT but no DSP.  */
 
-MIPS_CPU ("74kc", PROCESSOR_74KC, 33, 0) /* 74K with DSPr2.  */
-MIPS_CPU ("74kf2_1", PROCESSOR_74KF2_1, 33, 0)
-MIPS_CPU ("74kf", PROCESSOR_74KF2_1, 33, 0)
-MIPS_CPU ("74kf1_1", PROCESSOR_74KF1_1, 33, 0)
-MIPS_CPU ("74kfx", PROCESSOR_74KF1_1, 33, 0)
-MIPS_CPU ("74kx", PROCESSOR_74KF1_1, 33, 0)
-MIPS_CPU ("74kf3_2", PROCESSOR_74KF3_2, 33, 0)
+MIPS_CPU ("74kc", PROCESSOR_74KC, 33, PTF_AVOID_IMADD) /* 74K with DSPr2.  */
+MIPS_CPU ("74kf2_1", PROCESSOR_74KF2_1, 33, PTF_AVOID_IMADD)
+MIPS_CPU ("74kf", PROCESSOR_74KF2_1, 33, PTF_AVOID_IMADD)
+MIPS_CPU ("74kf1_1", PROCESSOR_74KF1_1, 33, PTF_AVOID_IMADD)
+MIPS_CPU ("74kfx", PROCESSOR_74KF1_1, 33, PTF_AVOID_IMADD)
+MIPS_CPU ("74kx", PROCESSOR_74KF1_1, 33, PTF_AVOID_IMADD)
+MIPS_CPU ("74kf3_2", PROCESSOR_74KF3_2, 33, PTF_AVOID_IMADD)
 
 MIPS_CPU ("1004kc", PROCESSOR_24KC, 33, 0) /* 1004K with MT/DSP.  */
 MIPS_CPU ("1004kf2_1", PROCESSOR_24KF2_1, 33, 0)
diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index e4ab271..e3469da 100644
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -16862,6 +16862,21 @@  mips_option_override (void)
     warning (0, "the %qs architecture does not support branch-likely"
 	     " instructions", mips_arch_info->name);
 
+  /* If the user hasn't specified -mimadd or -mno-imadd set
+     MASK_IMADD based on the target architecture and tuning
+     flags.  */
+  if ((target_flags_explicit & MASK_IMADD) == 0)
+    {
+      if (ISA_HAS_MADD_MSUB &&
+          (mips_tune_info->tune_flags & PTF_AVOID_IMADD) == 0)
+	target_flags |= MASK_IMADD;
+      else
+	target_flags &= ~MASK_IMADD;
+    }
+  else if (TARGET_IMADD && !ISA_HAS_MADD_MSUB)
+    warning (0, "the %qs architecture does not support madd or msub"
+	     " instructions", mips_arch_info->name);
+
   /* The effect of -mabicalls isn't defined for the EABI.  */
   if (mips_abi == ABI_EABI && TARGET_ABICALLS)
     {
diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 0db3698..dd694f3 100644
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -47,8 +47,15 @@  extern int target_flags_explicit;
    PTF_AVOID_BRANCHLIKELY
 	Set if it is usually not profitable to use branch-likely instructions
 	for this target, typically because the branches are always predicted
-	taken and so incur a large overhead when not taken.  */
-#define PTF_AVOID_BRANCHLIKELY 0x1
+	taken and so incur a large overhead when not taken.
+
+   PTF_AVOID_IMADD
+	Set if it is usually not profitable to use the integer MADD or MSUB
+	instructions because of the overhead of getting the result out of
+	the HI/LO registers.  */
+
+#define PTF_AVOID_BRANCHLIKELY	0x1
+#define PTF_AVOID_IMADD		0x2
 
 /* Information about one recognized processor.  Defined here for the
    benefit of TARGET_CPU_CPP_BUILTINS.  */
@@ -874,14 +881,13 @@  struct mips_cpu_info {
 				 && !TARGET_MIPS16)
 
 /* ISA has integer multiply-accumulate instructions, madd and msub.  */
-#define ISA_HAS_MADD_MSUB	((ISA_MIPS32				\
-				  || ISA_MIPS32R2			\
-				  || ISA_MIPS64				\
-				  || ISA_MIPS64R2)			\
-				 && !TARGET_MIPS16)
+#define ISA_HAS_MADD_MSUB	(ISA_MIPS32				\
+				 || ISA_MIPS32R2			\
+				 || ISA_MIPS64				\
+				 || ISA_MIPS64R2)
 
 /* Integer multiply-accumulate instructions should be generated.  */
-#define GENERATE_MADD_MSUB      (ISA_HAS_MADD_MSUB && !TUNE_74K)
+#define GENERATE_MADD_MSUB	(TARGET_IMADD && !TARGET_MIPS16)
 
 /* ISA has floating-point madd and msub instructions 'd = a * b [+-] c'.  */
 #define ISA_HAS_FP_MADD4_MSUB4  ISA_HAS_FP4
diff --git a/gcc/config/mips/mips.opt b/gcc/config/mips/mips.opt
index f9e88b3..e11710d 100644
--- a/gcc/config/mips/mips.opt
+++ b/gcc/config/mips/mips.opt
@@ -58,6 +58,10 @@  mmad
 Target Report Var(TARGET_MAD)
 Use PMC-style 'mad' instructions
 
+mimadd
+Target Report Mask(IMADD)
+Use integer madd/msub instructions
+
 march=
 Target RejectNegative Joined Var(mips_arch_option) ToLower Enum(mips_arch_opt_value)
 -march=ISA	Generate code for the given ISA
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 9b8b36a..3054e5c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -766,7 +766,7 @@  Objective-C and Objective-C++ Dialects}.
 -mcheck-zero-division  -mno-check-zero-division @gol
 -mdivide-traps  -mdivide-breaks @gol
 -mmemcpy  -mno-memcpy  -mlong-calls  -mno-long-calls @gol
--mmad  -mno-mad  -mfused-madd  -mno-fused-madd  -nocpp @gol
+-mmad -mno-mad -mimadd -mno-imadd -mfused-madd  -mno-fused-madd  -nocpp @gol
 -mfix-24k -mno-fix-24k @gol
 -mfix-r4000  -mno-fix-r4000  -mfix-r4400  -mno-fix-r4400 @gol
 -mfix-r10000 -mno-fix-r10000  -mfix-vr4120  -mno-fix-vr4120 @gol
@@ -16481,6 +16481,15 @@  This option has no effect on abicalls code.  The default is
 Enable (disable) use of the @code{mad}, @code{madu} and @code{mul}
 instructions, as provided by the R4650 ISA@.
 
+@item -mimadd
+@itemx -mno-imadd
+@opindex mimadd
+@opindex mno-imadd
+Enable (disable) use of the @code{madd} and @code{msub} integer
+instructions.  The default is @option{-mimadd} on architectures
+that support @code{madd} and @code{msub} except for the 74k 
+architecture where it was found to generate slower code.
+
 @item -mfused-madd
 @itemx -mno-fused-madd
 @opindex mfused-madd