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Re: [Patch, AVR]: Fix PR49687: Better widening mul 16=8*8
- From: Georg-Johann Lay <avr at gjlay dot de>
- To: Bernd Schmidt <bernds at codesourcery dot com>
- Cc: Andrew Stubbs <andrew dot stubbs at gmail dot com>, gcc-patches at gcc dot gnu dot org, Anatoly Sokolov <aesok at post dot ru>, Denis Chertykov <chertykov at gmail dot com>, Eric Weddington <eric dot weddington at atmel dot com>
- Date: Tue, 12 Jul 2011 13:51:01 +0200
- Subject: Re: [Patch, AVR]: Fix PR49687: Better widening mul 16=8*8
- References: <4E1C2384.5030906@gjlay.de> <4E1C2A53.70607@codesourcery.com> <4E1C2BF5.8070407@codesourcery.com>
Bernd Schmidt wrote:
> On 07/12/11 13:04, Andrew Stubbs wrote:
>> On 12/07/11 11:35, Georg-Johann Lay wrote:
>>> +(define_insn "*mulsu"
>>> + [(set (match_operand:HI 0
>>> "register_operand" "=r")
>>> + (mult:HI (sign_extend:HI (match_operand:QI 1
>>> "register_operand" "a"))
>>> + (zero_extend:HI (match_operand:QI 2
>>> "register_operand" "a"))))]
>>> + "AVR_HAVE_MUL"
>>> + "mulsu %1,%2
>>> + movw %0,r0
>>> + clr __zero_reg__"
>>> + [(set_attr "length" "3")
>>> + (set_attr "cc" "clobber")])
>>> +
>>> +(define_insn "*mulus"
>>> + [(set (match_operand:HI 0
>>> "register_operand" "=r")
>>> + (mult:HI (zero_extend:HI (match_operand:QI 1
>>> "register_operand" "a"))
>>> + (sign_extend:HI (match_operand:QI 2
>>> "register_operand" "a"))))]
>>> + "AVR_HAVE_MUL"
>>> + "mulsu %2,%1
>>> + movw %0,r0
>>> + clr __zero_reg__"
>>> + [(set_attr "length" "3")
>>> + (set_attr "cc" "clobber")])
>> 1. You should name that "usmulqihi3" (no star), so the optimizers can
>> see it.
>>
>> 2. There's no need to define both of these. For one thing, putting a '%'
>> at the start of the constraint list for operand 1 does precisely this,
>
> Unfortunately it doesn't. It won't swap the sign/zero-extend.
>
>
> Bernd
Thanks for clarification.
Here is version #3 of the patch with additional insn similar to
usmulqihi3 but with operands swapped ("*sumulqihi3").
Ok to commit?
Johann
PR target/49687
* config/avr/avr.md (mulhi3): Use register_or_s8_u8_operand for
operand2 and expand appropriately if there is a CONST_INT in
operand2.
(usmulqihi3): New insn.
(*sumulqihi3): New insn.
(mulsqihi3): New insn.
(muluqihi3): New insn.
(*muluqihi3.uconst): New insn_and_split.
(*muluqihi3.sconst): New insn_and_split.
(*mulsqihi3.sconst): New insn_and_split.
(*mulsqihi3.uconst): New insn_and_split.
(*ashifthi3.signx.const): New insn_and_split.
(*ashifthi3.signx.const7): New insn_and_split.
(*ashifthi3.zerox.const): New insn_and_split.
* config/avr/avr.c (avr_rtx_costs): Report costs of above insns.
(avr_gate_split1): New function.
* config/avr/avr-protos.h (avr_gate_split1): New prototype.
* config/avr/predicates.md (const_2_to_7_operand): New.
(const_2_to_6_operand): New.
(u8_operand): New.
(s8_operand): New.
(register_or_s8_u8_operand): New.
Index: config/avr/predicates.md
===================================================================
--- config/avr/predicates.md (revision 176136)
+++ config/avr/predicates.md (working copy)
@@ -73,6 +73,16 @@ (define_predicate "const_0_to_7_operand"
(and (match_code "const_int")
(match_test "IN_RANGE (INTVAL (op), 0, 7)")))
+;; Return 1 if OP is constant integer 2..7 for MODE.
+(define_predicate "const_2_to_7_operand"
+ (and (match_code "const_int")
+ (match_test "IN_RANGE (INTVAL (op), 2, 7)")))
+
+;; Return 1 if OP is constant integer 2..6 for MODE.
+(define_predicate "const_2_to_6_operand"
+ (and (match_code "const_int")
+ (match_test "IN_RANGE (INTVAL (op), 2, 6)")))
+
;; Returns true if OP is either the constant zero or a register.
(define_predicate "reg_or_0_operand"
(ior (match_operand 0 "register_operand")
@@ -156,3 +166,17 @@ (define_predicate "const_8_16_24_operand
(and (match_code "const_int")
(match_test "8 == INTVAL(op) || 16 == INTVAL(op) || 24 == INTVAL(op)")))
+;; Unsigned CONST_INT that fits in 8 bits, i.e. 0..255.
+(define_predicate "u8_operand"
+ (and (match_code "const_int")
+ (match_test "IN_RANGE (INTVAL (op), 0, 255)")))
+
+;; Signed CONST_INT that fits in 8 bits, i.e. -128..127.
+(define_predicate "s8_operand"
+ (and (match_code "const_int")
+ (match_test "IN_RANGE (INTVAL (op), -128, 127)")))
+
+(define_predicate "register_or_s8_u8_operand"
+ (ior (match_operand 0 "register_operand")
+ (match_operand 0 "u8_operand")
+ (match_operand 0 "s8_operand")))
Index: config/avr/avr.md
===================================================================
--- config/avr/avr.md (revision 176136)
+++ config/avr/avr.md (working copy)
@@ -1017,19 +1017,249 @@ (define_insn "umulqihi3"
[(set_attr "length" "3")
(set_attr "cc" "clobber")])
+(define_insn "usmulqihi3"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (zero_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (sign_extend:HI (match_operand:QI 2 "register_operand" "a"))))]
+ "AVR_HAVE_MUL"
+ "mulsu %2,%1
+ movw %0,r0
+ clr __zero_reg__"
+ [(set_attr "length" "3")
+ (set_attr "cc" "clobber")])
+
+;; Above insn is not canonicalized by insn combine, so here is a version with
+;; operands swapped.
+
+(define_insn "*sumulqihi3"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (zero_extend:HI (match_operand:QI 2 "register_operand" "a"))))]
+ "AVR_HAVE_MUL"
+ "mulsu %1,%2
+ movw %0,r0
+ clr __zero_reg__"
+ [(set_attr "length" "3")
+ (set_attr "cc" "clobber")])
+
+;******************************************************************************
+; mul HI: $1 = sign/zero-extend, $2 = small constant
+;******************************************************************************
+
+(define_insn_and_split "*muluqihi3.uconst"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (zero_extend:HI (match_operand:QI 1 "register_operand" "r"))
+ (match_operand:HI 2 "u8_operand" "M")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; umulqihi3
+ (set (match_dup 0)
+ (mult:HI (zero_extend:HI (match_dup 1))
+ (zero_extend:HI (match_dup 3))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]),
+ QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+(define_insn_and_split "*muluqihi3.sconst"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (zero_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (match_operand:HI 2 "s8_operand" "n")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; usmulqihi3
+ (set (match_dup 0)
+ (mult:HI (zero_extend:HI (match_dup 1))
+ (sign_extend:HI (match_dup 3))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]),
+ QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+(define_insn_and_split "*mulsqihi3.sconst"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "d"))
+ (match_operand:HI 2 "s8_operand" "n")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; mulqihi3
+ (set (match_dup 0)
+ (mult:HI (sign_extend:HI (match_dup 1))
+ (sign_extend:HI (match_dup 3))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]),
+ QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+(define_insn_and_split "*mulsqihi3.uconst"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (mult:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (match_operand:HI 2 "u8_operand" "M")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; usmulqihi3
+ (set (match_dup 0)
+ (mult:HI (zero_extend:HI (match_dup 3))
+ (sign_extend:HI (match_dup 1))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]),
+ QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+
+;; The EXTEND of $1 only appears in combine, we don't see it in expand so that
+;; expand decides to use ASHIFT instead of MUL because ASHIFT costs are cheaper
+;; at that time. Fix that.
+
+(define_insn_and_split "*ashifthi3.signx.const"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (ashift:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "d"))
+ (match_operand:HI 2 "const_2_to_6_operand" "I")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; mulqihi3
+ (set (match_dup 0)
+ (mult:HI (sign_extend:HI (match_dup 1))
+ (sign_extend:HI (match_dup 3))))]
+ {
+ operands[2] = GEN_INT (1 << INTVAL (operands[2]));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+(define_insn_and_split "*ashifthi3.signx.const7"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (ashift:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (const_int 7)))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; usmulqihi3
+ (set (match_dup 0)
+ (mult:HI (zero_extend:HI (match_dup 3))
+ (sign_extend:HI (match_dup 1))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (1 << 7, QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+(define_insn_and_split "*ashifthi3.zerox.const"
+ [(set (match_operand:HI 0 "register_operand" "=r")
+ (ashift:HI (zero_extend:HI (match_operand:QI 1 "register_operand" "r"))
+ (match_operand:HI 2 "const_2_to_7_operand" "I")))]
+ "AVR_HAVE_MUL
+ && avr_gate_split1()"
+ { gcc_unreachable(); }
+ "&& 1"
+ [(set (match_dup 3)
+ (match_dup 2))
+ ; umulqihi3
+ (set (match_dup 0)
+ (mult:HI (zero_extend:HI (match_dup 1))
+ (zero_extend:HI (match_dup 3))))]
+ {
+ operands[2] = GEN_INT (trunc_int_for_mode (1 << INTVAL (operands[2]),
+ QImode));
+ operands[3] = gen_reg_rtx (QImode);
+ })
+
+;******************************************************************************
+; mul HI: $1 = sign/zero-extend, $2 = reg
+;******************************************************************************
+
+(define_insn "mulsqihi3"
+ [(set (match_operand:HI 0 "register_operand" "=&r")
+ (mult:HI (sign_extend:HI (match_operand:QI 1 "register_operand" "a"))
+ (match_operand:HI 2 "register_operand" "a")))]
+ "AVR_HAVE_MUL"
+ "mulsu %1,%A2
+ movw %0,r0
+ mul %1,%B2
+ add %B0,r0
+ clr __zero_reg__"
+ [(set_attr "length" "5")
+ (set_attr "cc" "clobber")])
+
+(define_insn "muluqihi3"
+ [(set (match_operand:HI 0 "register_operand" "=&r")
+ (mult:HI (zero_extend:HI (match_operand:QI 1 "register_operand" "r"))
+ (match_operand:HI 2 "register_operand" "r")))]
+ "AVR_HAVE_MUL"
+ "mul %1,%A2
+ movw %0,r0
+ mul %1,%B2
+ add %B0,r0
+ clr __zero_reg__"
+ [(set_attr "length" "5")
+ (set_attr "cc" "clobber")])
+
+;******************************************************************************
+
(define_expand "mulhi3"
[(set (match_operand:HI 0 "register_operand" "")
(mult:HI (match_operand:HI 1 "register_operand" "")
- (match_operand:HI 2 "register_operand" "")))]
+ (match_operand:HI 2 "register_or_s8_u8_operand" "")))]
""
- "
-{
- if (!AVR_HAVE_MUL)
- {
- emit_insn (gen_mulhi3_call (operands[0], operands[1], operands[2]));
- DONE;
- }
-}")
+ {
+ if (!AVR_HAVE_MUL)
+ {
+ if (!register_operand (operands[2], HImode))
+ operands[2] = force_reg (HImode, operands[2]);
+
+ emit_insn (gen_mulhi3_call (operands[0], operands[1], operands[2]));
+ DONE;
+ }
+
+ /* For small constants we can do better by extending them on the fly.
+ The constant can be loaded in one instruction and the widening
+ multiplication is shorter. First try the unsigned variant because it
+ allows constraint "d" instead of "a" for the signed version. */
+
+ if (u8_operand (operands[2], HImode))
+ {
+ rtx x = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]), QImode));
+ emit_insn (gen_muluqihi3 (operands[0],
+ force_reg (QImode, x), operands[1]));
+ DONE;
+ }
+
+ if (s8_operand (operands[2], HImode))
+ {
+ rtx x = GEN_INT (trunc_int_for_mode (INTVAL (operands[2]), QImode));
+ emit_insn (gen_mulsqihi3 (operands[0],
+ force_reg (QImode, x), operands[1]));
+ DONE;
+ }
+
+ if (!register_operand (operands[2], HImode))
+ operands[2] = force_reg (HImode, operands[2]);
+ })
(define_insn "*mulhi3_enh"
[(set (match_operand:HI 0 "register_operand" "=&r")
Index: config/avr/avr-protos.h
===================================================================
--- config/avr/avr-protos.h (revision 176136)
+++ config/avr/avr-protos.h (working copy)
@@ -117,3 +117,4 @@ extern int class_max_nregs (enum reg_cla
#ifdef REAL_VALUE_TYPE
extern void asm_output_float (FILE *file, REAL_VALUE_TYPE n);
#endif
+extern bool avr_gate_split1(void);
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c (revision 176141)
+++ config/avr/avr.c (working copy)
@@ -5466,7 +5466,42 @@ avr_rtx_costs (rtx x, int codearg, int o
case HImode:
if (AVR_HAVE_MUL)
- *total = COSTS_N_INSNS (!speed ? 7 : 10);
+ {
+ rtx op0 = XEXP (x, 0);
+ rtx op1 = XEXP (x, 1);
+ enum rtx_code code0 = GET_CODE (op0);
+ enum rtx_code code1 = GET_CODE (op1);
+ bool ex0 = SIGN_EXTEND == code0 || ZERO_EXTEND == code0;
+ bool ex1 = SIGN_EXTEND == code1 || ZERO_EXTEND == code1;
+
+ if (ex0
+ && (u8_operand (op1, HImode)
+ || s8_operand (op1, HImode)))
+ {
+ *total = COSTS_N_INSNS (!speed ? 4 : 6);
+ return true;
+ }
+ if (ex0
+ && register_operand (op1, HImode))
+ {
+ *total = COSTS_N_INSNS (!speed ? 5 : 8);
+ return true;
+ }
+ else if (ex0 || ex1)
+ {
+ *total = COSTS_N_INSNS (!speed ? 3 : 5);
+ return true;
+ }
+ else if (register_operand (op0, HImode)
+ && (u8_operand (op1, HImode)
+ || s8_operand (op1, HImode)))
+ {
+ *total = COSTS_N_INSNS (!speed ? 6 : 9);
+ return true;
+ }
+ else
+ *total = COSTS_N_INSNS (!speed ? 7 : 10);
+ }
else if (!speed)
*total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 2 : 1);
else
@@ -5549,6 +5584,17 @@ avr_rtx_costs (rtx x, int codearg, int o
break;
case HImode:
+ if (AVR_HAVE_MUL)
+ {
+ if (const_2_to_7_operand (XEXP (x, 1), HImode)
+ && (SIGN_EXTEND == GET_CODE (XEXP (x, 0))
+ || ZERO_EXTEND == GET_CODE (XEXP (x, 0))))
+ {
+ *total = COSTS_N_INSNS (!speed ? 4 : 6);
+ return true;
+ }
+ }
+
if (GET_CODE (XEXP (x, 1)) != CONST_INT)
{
*total = COSTS_N_INSNS (!speed ? 5 : 41);
@@ -6881,4 +6927,29 @@ avr_expand_builtin (tree exp, rtx target
}
+/* FIXME: We compose some insns by means of insn combine
+ and split them in split1. We don't want IRA/reload
+ to combine them to the original insns again because
+ that avoid some CSE optimizations if constants are
+ involved. If IRA/reload combines, the recombined
+ insns get split again after reload, but then CSE
+ does not take place.
+ It appears that at present there is no other way
+ to take away the insn from IRA. Notice that split1
+ runs unconditionally so that all our insns will get
+ split no matter of command line options. */
+
+#include "tree-pass.h"
+
+bool
+avr_gate_split1 (void)
+{
+ if (current_pass->static_pass_number
+ < pass_match_asm_constraints.pass.static_pass_number)
+ return true;
+
+ return false;
+}
+
+
#include "gt-avr.h"