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Re: AMD K6 support
On Thu, Aug 20, 1998 at 08:02:21AM -0400, John Carr wrote:
>
> The parameters in your patch conflict with the latest optimization
> guide from AMD (for example, AMD says fpmul and imul take 2 cycles).
>
> I am also working on AMD K6 optimizations for egcs. I'll send my
> patch for discussion this weekend.
I did not yet look at your patch, sorry.
I updated mine though and fixed a few typos (thanks for pointing it out,
Kamil) and experimented with my fp code to get better results. Also, the
numbers used should be closer to the AMD specs, now. fpmul is 3 cycles and
cost_imul is 4. You can argue about these, but at least for imul 4 isn't
unrealistic: AMD docs say 2-3 cycles latency and 2-3 cycles throughput ...
My results went worse when I further decreased those values.
I think your patch is much more complicated and will be included into egcs
later, but for now, I'm happy with my lightweight patch and I hope others
will be, too.
Have a look at the appended diff.
--
+--------------------------------------------------------------+
| cand.phys. Kurt Garloff C1-O4-101 (Chemiegeb"aude) |
|Lehrstuhl Hochfrequenztechnik (Fakult"at f"ur Elektrotechnik)|
| Universit"at Dortmund D - 44221 Dortmund |
| Tel.: (0231) 755-3947 Fax: (0231) 755-4631 |
| garloff@hft.e-technik.uni-dortmund.de |
| Public PGP key available ! |
+--------------------------------------------------------------+
--- gcc/ChangeLog.orig Wed Aug 12 10:56:17 1998
+++ gcc/ChangeLog Mon Aug 24 09:47:52 1998
@@ -1,3 +1,10 @@
+Mon Aug 24 09:43:50 1998 Kurt Garloff (K.Garloff@ping.de)
+
+ * config/i386/i386.md: Added description and scheduling params
+ for AMD K6
+ * config/i386/i386.h: Likewise
+ * config/i386/i386.c: Likewise
+
Mon Aug 3 23:43:55 PDT 1998 Jeff Law (law@cygnus.com)
* version.c: Bump for snapshot.
--- gcc/config/i386/i386.md.orig Wed Aug 12 10:56:17 1998
+++ gcc/config/i386/i386.md Mon Aug 24 09:39:14 1998
@@ -97,6 +97,10 @@
3 0)
(define_function_unit "fp" 1 0
+ (and (eq_attr "type" "fpop") (eq_attr "cpu" "amdk6"))
+ 2 0)
+
+(define_function_unit "fp" 1 0
(and (eq_attr "type" "fpmul") (eq_attr "cpu" "pentium"))
7 0)
@@ -105,6 +109,14 @@
5 0)
(define_function_unit "fp" 1 0
+ (and (eq_attr "type" "fpmul") (eq_attr "cpu" "pentiumpro"))
+ 4 0)
+
+(define_function_unit "fp" 1 0
+ (and (eq_attr "type" "fpmul") (eq_attr "cpu" "amdk6"))
+ 3 0)
+
+(define_function_unit "fp" 1 0
(and (eq_attr "type" "idiv") (eq_attr "cpu" "pentiumpro"))
10 10)
@@ -113,13 +125,21 @@
6 0)
(define_function_unit "fp" 1 0
- (eq_attr "type" "fpdiv")
+ (and (eq_attr "type" "fpdiv") (eq_attr "cpu" "!amdk6"))
10 10)
(define_function_unit "fp" 1 0
- (eq_attr "type" "fld")
+ (and (eq_attr "type" "fpdiv") (eq_attr "cpu" "amdk6"))
+ 10 8)
+
+(define_function_unit "fp" 1 0
+ (and (eq_attr "type" "fld") (eq_attr "cpu" "!amdk6"))
1 0)
+(define_function_unit "fp" 1 0
+ (and (eq_attr "type" "fld") (eq_attr "cpu" "amdk6"))
+ 2 0)
+
(define_function_unit "integer" 1 0
(and (eq_attr "type" "integer") (eq_attr "cpu" "!i386"))
2 0)
@@ -140,7 +160,7 @@
;; Processor type -- this attribute must exactly match the processor_type
;; enumeration in i386.h.
-(define_attr "cpu" "i386,i486,pentium,pentiumpro"
+(define_attr "cpu" "i386,i486,pentium,pentiumpro,amdk6"
(const (symbol_ref "ix86_cpu")))
(define_insn "tstsi_1"
@@ -989,7 +1009,7 @@
operands[1] = i386_sext16_if_const (operands[1]);
return AS2 (mov%L0,%k1,%k0);
}
- if (TARGET_PENTIUMPRO)
+ if (TARGET_PENTIUMPRO || TARGET_AMDK6)
{
/* movzwl is faster than movw on the Pentium Pro,
* although not as fast as an aligned movl. */
--- gcc/config/i386/i386.h.orig Wed Aug 12 10:56:06 1998
+++ gcc/config/i386/i386.h Mon Aug 24 09:25:15 1998
@@ -1,5 +1,5 @@
/* Definitions of target machine for GNU compiler for Intel X86
- (386, 486, Pentium).
+ (386, 486, Pentium, PentiumPro, AmdK6).
Copyright (C) 1988, 92, 94, 95, 96, 97, 1998 Free Software Foundation, Inc.
This file is part of GNU CC.
@@ -155,20 +155,23 @@
#define TARGET_486 (ix86_cpu == PROCESSOR_I486)
#define TARGET_PENTIUM (ix86_cpu == PROCESSOR_PENTIUM)
#define TARGET_PENTIUMPRO (ix86_cpu == PROCESSOR_PENTIUMPRO)
+#define TARGET_AMDK6 (ix86_cpu == PROCESSOR_AMDK6)
#define TARGET_USE_LEAVE (ix86_cpu == PROCESSOR_I386)
-#define TARGET_PUSH_MEMORY (ix86_cpu == PROCESSOR_I386)
+#define TARGET_PUSH_MEMORY (ix86_cpu == PROCESSOR_I386 || ix86_cpu == PROCESSOR_AMDK6)
#define TARGET_ZERO_EXTEND_WITH_AND (ix86_cpu != PROCESSOR_I386 \
- && ix86_cpu != PROCESSOR_PENTIUMPRO)
+ && ix86_cpu != PROCESSOR_PENTIUMPRO && ix86_cpu != PROCESSOR_AMDK6)
#define TARGET_DOUBLE_WITH_ADD (ix86_cpu != PROCESSOR_I386)
-#define TARGET_USE_BIT_TEST (ix86_cpu == PROCESSOR_I386)
+#define TARGET_USE_BIT_TEST (ix86_cpu == PROCESSOR_I386) /* || ix86_cpu == PROCESSOR_AMDK5) */
#define TARGET_UNROLL_STRLEN (ix86_cpu != PROCESSOR_I386)
#define TARGET_USE_Q_REG (ix86_cpu == PROCESSOR_PENTIUM \
- || ix86_cpu == PROCESSOR_PENTIUMPRO)
-#define TARGET_USE_ANY_REG (ix86_cpu == PROCESSOR_I486)
+ || ix86_cpu == PROCESSOR_PENTIUMPRO /*|| ix86_cpu == PROCESSOR_AMDK6*/)
+#define TARGET_USE_ANY_REG (ix86_cpu == PROCESSOR_I486 || ix86_cpu == PROCESSOR_AMDK6)
#define TARGET_CMOVE (ix86_arch == PROCESSOR_PENTIUMPRO)
-#define TARGET_DEEP_BRANCH_PREDICTION (ix86_cpu == PROCESSOR_PENTIUMPRO)
+#define TARGET_DEEP_BRANCH_PREDICTION (ix86_cpu == PROCESSOR_PENTIUMPRO || ix86_cpu == PROCESSOR_AMDK6)
#define TARGET_STACK_PROBE (target_flags & MASK_STACK_PROBE)
+#define ISSUE_RATE 1 /* (TARGET_AMDK6 ? 2 : 1) */
+
#define TARGET_SWITCHES \
{ { "80387", MASK_80387 }, \
{ "no-80387", -MASK_80387 }, \
@@ -181,6 +184,7 @@
{ "no-486", 0 }, \
{ "pentium", 0 }, \
{ "pentiumpro", 0 }, \
+ { "amdk6", 0 }, \
{ "rtd", MASK_RTD }, \
{ "no-rtd", -MASK_RTD }, \
{ "align-double", MASK_ALIGN_DOUBLE }, \
@@ -219,7 +223,8 @@
{PROCESSOR_I386, /* 80386 */
PROCESSOR_I486, /* 80486DX, 80486SX, 80486DX[24] */
PROCESSOR_PENTIUM,
- PROCESSOR_PENTIUMPRO};
+ PROCESSOR_PENTIUMPRO,
+ PROCESSOR_AMDK6};
#define PROCESSOR_I386_STRING "i386"
#define PROCESSOR_I486_STRING "i486"
@@ -227,6 +232,7 @@
#define PROCESSOR_PENTIUM_STRING "pentium"
#define PROCESSOR_I686_STRING "i686"
#define PROCESSOR_PENTIUMPRO_STRING "pentiumpro"
+#define PROCESSOR_AMDK6_STRING "amdk6"
extern enum processor_type ix86_cpu;
@@ -240,6 +246,8 @@
? PROCESSOR_PENTIUM \
: ((enum processor_type) TARGET_CPU_DEFAULT == PROCESSOR_PENTIUMPRO) \
? PROCESSOR_PENTIUMPRO \
+ : ((enum processor_type) TARGET_CPU_DEFAULT == PROCESSOR_AMDK6) \
+ ? PROCESSOR_AMDK6 \
: PROCESSOR_I386
#define PROCESSOR_DEFAULT_STRING \
((enum processor_type) TARGET_CPU_DEFAULT == PROCESSOR_I486) \
@@ -248,6 +256,8 @@
? PROCESSOR_PENTIUM_STRING \
: ((enum processor_type) TARGET_CPU_DEFAULT == PROCESSOR_PENTIUMPRO) \
? PROCESSOR_PENTIUMPRO_STRING \
+ : ((enum processor_type) TARGET_CPU_DEFAULT == PROCESSOR_AMDK6_STRING) \
+ ? PROCESSOR_AMDK6_STRING \
: PROCESSOR_I386_STRING
/* This macro is similar to `TARGET_SWITCHES' but defines names of
@@ -301,7 +311,9 @@
%{mno-pentium:-mcpu=i486 -march=i486} \
%{mpentium:-mcpu=pentium} \
%{mno-pentiumpro:-mcpu=pentium} \
-%{mpentiumpro:-mcpu=pentiumpro}}"
+%{mpentiumpro:-mcpu=pentiumpro} \
+%{mno-amdk6:-mcpu=pentium} \
+%{mamdk6:-mcpu=amdk6}}"
#endif
#define CPP_486_SPEC "%{!ansi:-Di486} -D__i486 -D__i486__"
@@ -309,6 +321,8 @@
-D__i586 -D__i586__ -D__pentium -D__pentium__"
#define CPP_686_SPEC "%{!ansi:-Di686 -Dpentiumpro} \
-D__i686 -D__i686__ -D__pentiumpro -D__pentiumpro__"
+#define CPP_AMDK6_SPEC "%{!ansi:-Di686 -Damdk6} \
+ -D__i586 -D__i586__ -D__amdk6 -D__amdk6__"
#ifndef CPP_CPU_DEFAULT_SPEC
#if TARGET_CPU_DEFAULT == 1
@@ -320,10 +334,14 @@
#if TARGET_CPU_DEFAULT == 3
#define CPP_CPU_DEFAULT_SPEC "%(cpp_686)"
#else
+#if TARGET_CPU_DEFAULT == 4
+#define CPP_CPU_DEFAULT_SPEC "%(cpp_amdk6)"
+#else
#define CPP_CPU_DEFAULT_SPEC ""
#endif
#endif
#endif
+#endif
#endif /* CPP_CPU_DEFAULT_SPEC */
#ifndef CPP_CPU_SPEC
@@ -333,6 +351,7 @@
%{mcpu=i486:%(cpp_486)} %{m486:%(cpp_486)} \
%{mpentium:%(cpp_586)} %{mcpu=pentium:%(cpp_586)} \
%{mpentiumpro:%(cpp_686)} %{mcpu=pentiumpro:%(cpp_686)} \
+%{mamdk6:%(cpp_amdk6)} %{mcpu=amdk6:%(cpp_amdk6)} \
%{!mcpu*:%{!m486:%{!mpentium*:%(cpp_cpu_default)}}}"
#endif
@@ -358,6 +377,7 @@
{ "cpp_486", CPP_486_SPEC}, \
{ "cpp_586", CPP_586_SPEC}, \
{ "cpp_686", CPP_686_SPEC}, \
+ { "cpp_amdk6", CPP_AMDK6_SPEC}, \
{ "cpp_cpu_default", CPP_CPU_DEFAULT_SPEC }, \
{ "cpp_cpu", CPP_CPU_SPEC }, \
{ "cc1_cpu", CC1_CPU_SPEC }, \
--- gcc/config/i386/i386.c.orig Wed Aug 12 10:56:17 1998
+++ gcc/config/i386/i386.c Mon Aug 24 09:25:33 1998
@@ -100,7 +100,17 @@
17 /* cost of a divide/mod */
};
-struct processor_costs *ix86_cost = &pentium_cost;
+struct processor_costs amdk6_cost = {
+ 1, /* cost of an add instruction */
+ 1, /* cost of a lea instruction */
+ 3, /* variable shift costs */
+ 2, /* constant shift costs */
+ 4, /* cost of starting a multiply */
+ 0, /* cost of multiply per each bit set */
+ 18 /* cost of a divide/mod */
+};
+
+struct processor_costs *ix86_cost = &pentiumpro_cost;
#define AT_BP(mode) (gen_rtx_MEM ((mode), frame_pointer_rtx))
@@ -213,7 +223,9 @@
{PROCESSOR_I686_STRING, PROCESSOR_PENTIUMPRO, &pentiumpro_cost,
0, 0},
{PROCESSOR_PENTIUMPRO_STRING, PROCESSOR_PENTIUMPRO,
- &pentiumpro_cost, 0, 0}};
+ &pentiumpro_cost, 0, 0},
+ {PROCESSOR_AMDK6_STRING, PROCESSOR_AMDK6,
+ &amdk6_cost, 0, 0}};
int ptt_size = sizeof (processor_target_table) / sizeof (struct ptt);
@@ -306,7 +318,7 @@
/* The 486 suffers more from non-aligned cache line fills, and the
larger code size results in a larger cache foot-print and more misses.
- The 486 has a 16 byte cache line, pentium and pentiumpro have a 32 byte
+ The 486 has a 16 byte cache line, pentium, pentiumpro and K6 have a 32 byte
cache line. */
def_align = (TARGET_486) ? 4 : 2;
@@ -349,7 +361,7 @@
i386_align_funcs, MAX_CODE_ALIGN);
}
else
- i386_align_funcs = def_align;
+ i386_align_funcs = TARGET_AMDK6 ? 4: def_align;
/* Validate -mbranch-cost= value, or provide default. */
if (i386_branch_cost_string)