mips.md: Complete the unfinished R4000 multiply/shift errata workaround.

* config/mips/mips.md: Complete the unfinished R4000
	multiply/shift errata workaround.  Improve documentation.
	(hazard): Use TARGET_FIX_R4000 to decide whether an "imul" instruction
	has a hilo hazard.
	(mulsi3, mulsi3_internal, mulsi3_r4000): Use TARGET_FIX_R4000.
	(muldi3, muldi3_internal): Likewise.
	(muldi3_internal2): Remove, replacing with...
	(muldi3_mult3, muldi3_r4000): ...these new patterns.
	(mulsidi3): Take the errata into account.
	(mulsidi3_32bit): Remove, replacing with...
	(mulsidi3_32bit_internal, mulsidi3_32bit_r4000): ...these new patterns.
	(mulsidi3_64bit, mulsidi3_64bit_parts): Disable if TARGET_FIX_R4000.
	(umulsidi3): Take the errata into account.
	(umulsidi3_32bit): Remove, replacing with..
	(umulsidi3_32bit_internal, umulsidi3_32bit_r4000): ...these patterns.
	(umulsi3_highpart, umulsi3_highpart_internal): Disable if
	TARGET_FIX_R4000.
	(smulsi3_highpart, smulsi3_highpart_internal): Likewise.
	(smuldi3_highpart, umuldi3_highpart): Likewise.
	* doc/invoke.texi: Document the errata workaround.

From-SVN: r78622
This commit is contained in:
Maciej W. Rozycki 2004-02-28 21:06:01 +01:00 committed by Richard Sandiford
parent 4649040309
commit bddbfe5f67
3 changed files with 150 additions and 40 deletions

View File

@ -1,3 +1,26 @@
2004-02-28 Maciej W. Rozycki <macro@ds2.pg.gda.pl>
* config/mips/mips.md: Complete the unfinished R4000
multiply/shift errata workaround. Improve documentation.
(hazard): Use TARGET_FIX_R4000 to decide whether an "imul" instruction
has a hilo hazard.
(mulsi3, mulsi3_internal, mulsi3_r4000): Use TARGET_FIX_R4000.
(muldi3, muldi3_internal): Likewise.
(muldi3_internal2): Remove, replacing with...
(muldi3_mult3, muldi3_r4000): ...these new patterns.
(mulsidi3): Take the errata into account.
(mulsidi3_32bit): Remove, replacing with...
(mulsidi3_32bit_internal, mulsidi3_32bit_r4000): ...these new patterns.
(mulsidi3_64bit, mulsidi3_64bit_parts): Disable if TARGET_FIX_R4000.
(umulsidi3): Take the errata into account.
(umulsidi3_32bit): Remove, replacing with..
(umulsidi3_32bit_internal, umulsidi3_32bit_r4000): ...these patterns.
(umulsi3_highpart, umulsi3_highpart_internal): Disable if
TARGET_FIX_R4000.
(smulsi3_highpart, smulsi3_highpart_internal): Likewise.
(smuldi3_highpart, umuldi3_highpart): Likewise.
* doc/invoke.texi: Document the errata workaround.
2004-02-28 Maciej W. Rozycki <macro@ds2.pg.gda.pl>
* config/mips/mips-protos.h (mips_idiv_insns): Declare.

View File

@ -233,7 +233,7 @@
;; The r4000 multiplication patterns include an mflo instruction.
(and (eq_attr "type" "imul")
(ne (symbol_ref "TARGET_MIPS4000") (const_int 0)))
(ne (symbol_ref "TARGET_FIX_R4000") (const_int 0)))
(const_string "hilo")
(and (eq_attr "type" "hilo")
@ -1420,9 +1420,51 @@
(set_attr "length" "8")])
;; ??? The R4000 (only) has a cpu bug. If a double-word shift executes while
;; a multiply is in progress, it may give an incorrect result. Avoid
;; this by keeping the mflo with the mult on the R4000.
;; The original R4000 has a cpu bug. If a double-word or a variable
;; shift executes while an integer multiplication is in progress, the
;; shift may give an incorrect result. Avoid this by keeping the mflo
;; with the mult on the R4000.
;;
;; From "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0"
;; (also valid for MIPS R4000MC processors):
;;
;; "16. R4000PC, R4000SC: Please refer to errata 28 for an update to
;; this errata description.
;; The following code sequence causes the R4000 to incorrectly
;; execute the Double Shift Right Arithmetic 32 (dsra32)
;; instruction. If the dsra32 instruction is executed during an
;; integer multiply, the dsra32 will only shift by the amount in
;; specified in the instruction rather than the amount plus 32
;; bits.
;; instruction 1: mult rs,rt integer multiply
;; instruction 2-12: dsra32 rd,rt,rs doubleword shift
;; right arithmetic + 32
;; Workaround: A dsra32 instruction placed after an integer
;; multiply should not be one of the 11 instructions after the
;; multiply instruction."
;;
;; and:
;;
;; "28. R4000PC, R4000SC: The text from errata 16 should be replaced by
;; the following description.
;; All extended shifts (shift by n+32) and variable shifts (32 and
;; 64-bit versions) may produce incorrect results under the
;; following conditions:
;; 1) An integer multiply is currently executing
;; 2) These types of shift instructions are executed immediately
;; following an integer divide instruction.
;; Workaround:
;; 1) Make sure no integer multiply is running wihen these
;; instruction are executed. If this cannot be predicted at
;; compile time, then insert a "mfhi" to R0 instruction
;; immediately after the integer multiply instruction. This
;; will cause the integer multiply to complete before the shift
;; is executed.
;; 2) Separate integer divide and these two classes of shift
;; instructions by another instruction or a noop."
;;
;; These processors have PRId values of 0x00004220 and 0x00004300,
;; respectively.
(define_expand "mulsi3"
[(set (match_operand:SI 0 "register_operand" "")
@ -1432,7 +1474,7 @@
{
if (GENERATE_MULT3_SI || TARGET_MAD)
emit_insn (gen_mulsi3_mult3 (operands[0], operands[1], operands[2]));
else if (!TARGET_MIPS4000 || TARGET_MIPS16)
else if (!TARGET_FIX_R4000)
emit_insn (gen_mulsi3_internal (operands[0], operands[1], operands[2]));
else
emit_insn (gen_mulsi3_r4000 (operands[0], operands[1], operands[2]));
@ -1498,7 +1540,7 @@
(mult:SI (match_operand:SI 1 "register_operand" "d")
(match_operand:SI 2 "register_operand" "d")))
(clobber (match_scratch:SI 3 "=h"))]
"!TARGET_MIPS4000 || TARGET_MIPS16"
"!TARGET_FIX_R4000"
"mult\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "SI")])
@ -1509,7 +1551,7 @@
(match_operand:SI 2 "register_operand" "d")))
(clobber (match_scratch:SI 3 "=h"))
(clobber (match_scratch:SI 4 "=l"))]
"TARGET_MIPS4000 && !TARGET_MIPS16"
"TARGET_FIX_R4000"
"mult\t%1,%2\;mflo\t%0"
[(set_attr "type" "imul")
(set_attr "mode" "SI")
@ -1829,42 +1871,47 @@
(match_operand:DI 2 "register_operand" "")))]
"TARGET_64BIT"
{
if (GENERATE_MULT3_DI || TARGET_MIPS4000)
emit_insn (gen_muldi3_internal2 (operands[0], operands[1], operands[2]));
else
if (GENERATE_MULT3_DI)
emit_insn (gen_muldi3_mult3 (operands[0], operands[1], operands[2]));
else if (!TARGET_FIX_R4000)
emit_insn (gen_muldi3_internal (operands[0], operands[1], operands[2]));
else
emit_insn (gen_muldi3_r4000 (operands[0], operands[1], operands[2]));
DONE;
})
(define_insn "muldi3_mult3"
[(set (match_operand:DI 0 "register_operand" "=d")
(mult:DI (match_operand:DI 1 "register_operand" "d")
(match_operand:DI 2 "register_operand" "d")))
(clobber (match_scratch:DI 3 "=h"))
(clobber (match_scratch:DI 4 "=l"))]
"TARGET_64BIT && GENERATE_MULT3_DI"
"dmult\t%0,%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "DI")])
(define_insn "muldi3_internal"
[(set (match_operand:DI 0 "register_operand" "=l")
(mult:DI (match_operand:DI 1 "register_operand" "d")
(match_operand:DI 2 "register_operand" "d")))
(clobber (match_scratch:DI 3 "=h"))]
"TARGET_64BIT && !TARGET_MIPS4000"
"TARGET_64BIT && !TARGET_FIX_R4000"
"dmult\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "DI")])
(define_insn "muldi3_internal2"
(define_insn "muldi3_r4000"
[(set (match_operand:DI 0 "register_operand" "=d")
(mult:DI (match_operand:DI 1 "register_operand" "d")
(match_operand:DI 2 "register_operand" "d")))
(clobber (match_scratch:DI 3 "=h"))
(clobber (match_scratch:DI 4 "=l"))]
"TARGET_64BIT && (GENERATE_MULT3_DI || TARGET_MIPS4000)"
{
if (GENERATE_MULT3_DI)
return "dmult\t%0,%1,%2";
else
return "dmult\t%1,%2\;mflo\t%0";
}
"TARGET_64BIT && TARGET_FIX_R4000"
"dmult\t%1,%2\;mflo\t%0"
[(set_attr "type" "imul")
(set_attr "mode" "DI")
(set (attr "length")
(if_then_else (ne (symbol_ref "GENERATE_MULT3_DI") (const_int 0))
(const_int 4)
(const_int 8)))])
(set_attr "length" "8")])
;; ??? We could define a mulditi3 pattern when TARGET_64BIT.
@ -1877,25 +1924,43 @@
(clobber (scratch:DI))
(clobber (scratch:DI))
(clobber (scratch:DI))])]
""
"!TARGET_64BIT || !TARGET_FIX_R4000"
{
if (!TARGET_64BIT)
{
emit_insn (gen_mulsidi3_32bit (operands[0], operands[1], operands[2]));
if (!TARGET_FIX_R4000)
emit_insn (gen_mulsidi3_32bit_internal (operands[0], operands[1],
operands[2]));
else
emit_insn (gen_mulsidi3_32bit_r4000 (operands[0], operands[1],
operands[2]));
DONE;
}
})
(define_insn "mulsidi3_32bit"
(define_insn "mulsidi3_32bit_internal"
[(set (match_operand:DI 0 "register_operand" "=x")
(mult:DI
(sign_extend:DI (match_operand:SI 1 "register_operand" "d"))
(sign_extend:DI (match_operand:SI 2 "register_operand" "d"))))]
"!TARGET_64BIT"
"!TARGET_64BIT && !TARGET_FIX_R4000"
"mult\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "SI")])
(define_insn "mulsidi3_32bit_r4000"
[(set (match_operand:DI 0 "register_operand" "=d")
(mult:DI
(sign_extend:DI (match_operand:SI 1 "register_operand" "d"))
(sign_extend:DI (match_operand:SI 2 "register_operand" "d"))))
(clobber (match_scratch:DI 3 "=l"))
(clobber (match_scratch:DI 4 "=h"))]
"!TARGET_64BIT && TARGET_FIX_R4000"
"mult\t%1,%2\;mflo\t%L0;mfhi\t%M0"
[(set_attr "type" "imul")
(set_attr "mode" "SI")
(set_attr "length" "12")])
(define_insn_and_split "*mulsidi3_64bit"
[(set (match_operand:DI 0 "register_operand" "=d")
(mult:DI (match_operator:DI 1 "extend_operator"
@ -1905,7 +1970,8 @@
(clobber (match_scratch:DI 5 "=l"))
(clobber (match_scratch:DI 6 "=h"))
(clobber (match_scratch:DI 7 "=d"))]
"TARGET_64BIT && GET_CODE (operands[1]) == GET_CODE (operands[2])"
"TARGET_64BIT && !TARGET_FIX_R4000
&& GET_CODE (operands[1]) == GET_CODE (operands[2])"
"#"
"&& reload_completed"
[(parallel
@ -1956,7 +2022,8 @@
(match_operator:DI 4 "extend_operator" [(match_dup 2)])
(match_operator:DI 5 "extend_operator" [(match_dup 3)]))
(const_int 32)))]
"TARGET_64BIT && GET_CODE (operands[4]) == GET_CODE (operands[5])"
"TARGET_64BIT && !TARGET_FIX_R4000
&& GET_CODE (operands[4]) == GET_CODE (operands[5])"
{
if (GET_CODE (operands[4]) == SIGN_EXTEND)
return "mult\t%2,%3";
@ -1975,26 +2042,43 @@
(clobber (scratch:DI))
(clobber (scratch:DI))
(clobber (scratch:DI))])]
""
"!TARGET_64BIT || !TARGET_FIX_R4000"
{
if (!TARGET_64BIT)
{
emit_insn (gen_umulsidi3_32bit (operands[0], operands[1],
operands[2]));
if (!TARGET_FIX_R4000)
emit_insn (gen_umulsidi3_32bit_internal (operands[0], operands[1],
operands[2]));
else
emit_insn (gen_umulsidi3_32bit_r4000 (operands[0], operands[1],
operands[2]));
DONE;
}
})
(define_insn "umulsidi3_32bit"
(define_insn "umulsidi3_32bit_internal"
[(set (match_operand:DI 0 "register_operand" "=x")
(mult:DI
(zero_extend:DI (match_operand:SI 1 "register_operand" "d"))
(zero_extend:DI (match_operand:SI 2 "register_operand" "d"))))]
"!TARGET_64BIT"
"!TARGET_64BIT && !TARGET_FIX_R4000"
"multu\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "SI")])
(define_insn "umulsidi3_32bit_r4000"
[(set (match_operand:DI 0 "register_operand" "=d")
(mult:DI
(zero_extend:DI (match_operand:SI 1 "register_operand" "d"))
(zero_extend:DI (match_operand:SI 2 "register_operand" "d"))))
(clobber (match_scratch:DI 3 "=l"))
(clobber (match_scratch:DI 4 "=h"))]
"!TARGET_64BIT && TARGET_FIX_R4000"
"multu\t%1,%2\;mflo\t%L0;mfhi\t%M0"
[(set_attr "type" "imul")
(set_attr "mode" "SI")
(set_attr "length" "12")])
;; Widening multiply with negation.
(define_insn "*muls_di"
[(set (match_operand:DI 0 "register_operand" "=x")
@ -2064,7 +2148,7 @@
(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" ""))
(zero_extend:DI (match_operand:SI 2 "register_operand" "")))
(const_int 32))))]
""
"ISA_HAS_MULHI || !TARGET_FIX_R4000"
{
if (ISA_HAS_MULHI)
emit_insn (gen_umulsi3_highpart_mulhi_internal (operands[0], operands[1],
@ -2083,7 +2167,7 @@
(zero_extend:DI (match_operand:SI 2 "register_operand" "d")))
(const_int 32))))
(clobber (match_scratch:SI 3 "=l"))]
"!ISA_HAS_MULHI"
"!ISA_HAS_MULHI && !TARGET_FIX_R4000"
"multu\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "SI")
@ -2131,7 +2215,7 @@
(mult:DI (sign_extend:DI (match_operand:SI 1 "register_operand" ""))
(sign_extend:DI (match_operand:SI 2 "register_operand" "")))
(const_int 32))))]
""
"ISA_HAS_MULHI || !TARGET_FIX_R4000"
{
if (ISA_HAS_MULHI)
emit_insn (gen_smulsi3_highpart_mulhi_internal (operands[0], operands[1],
@ -2150,7 +2234,7 @@
(sign_extend:DI (match_operand:SI 2 "register_operand" "d")))
(const_int 32))))
(clobber (match_scratch:SI 3 "=l"))]
"!ISA_HAS_MULHI"
"!ISA_HAS_MULHI && !TARGET_FIX_R4000"
"mult\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "SI")
@ -2199,7 +2283,7 @@
(sign_extend:TI (match_operand:DI 2 "register_operand" "d")))
(const_int 64))))
(clobber (match_scratch:DI 3 "=l"))]
"TARGET_64BIT"
"TARGET_64BIT && !TARGET_FIX_R4000"
"dmult\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "DI")])
@ -2213,7 +2297,7 @@
(zero_extend:TI (match_operand:DI 2 "register_operand" "d")))
(const_int 64))))
(clobber (match_scratch:DI 3 "=l"))]
"TARGET_64BIT"
"TARGET_64BIT && !TARGET_FIX_R4000"
"dmultu\t%1,%2"
[(set_attr "type" "imul")
(set_attr "mode" "DI")])

View File

@ -8055,6 +8055,9 @@ Work around certain R4000 CPU errata:
@item
A double-word or a variable shift may give an incorrect result if executed
immediately after starting an integer division.
@item
A double-word or a variable shift may give an incorrect result if executed
while an integer multiplication is in progress.
@end itemize
@item -mfix-sb1