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cmd/compile/ssa: more aggressive constant folding 

Add rewrite rules that canonicalize the location
of constants in expressions, and fold conststants
that appear in operations that can be trivially
reassociated.

After this change, the compiler constant-folds
expressions like "4 + x - 1" and "4 & x & 1"

Benchmarks affected on darwin/amd64:

name                     old time/op    new time/op    delta
FmtFprintfInt-8            82.1ns ± 1%    81.7ns ± 1%  -0.46%  (p=0.023 n=8+9)
FmtFprintfIntInt-8          122ns ± 2%     120ns ± 2%  -1.48%  (p=0.047 n=10+10)
FmtManyArgs-8               493ns ± 0%     486ns ± 1%  -1.37%  (p=0.000 n=8+10)
Gzip-8                      230ms ± 0%     229ms ± 1%  -0.46%  (p=0.001 n=10+9)
HTTPClientServer-8         74.5µs ± 1%    73.7µs ± 1%  -1.11%  (p=0.000 n=10+10)
JSONDecode-8               51.7ms ± 0%    51.9ms ± 1%  +0.42%  (p=0.017 n=10+9)
RegexpMatchEasy0_32-8      82.6ns ± 1%    81.7ns ± 0%  -1.02%  (p=0.000 n=9+8)
RegexpMatchMedium_32-8      121ns ± 1%     120ns ± 1%  -1.48%  (p=0.001 n=10+10)
Revcomp-8                   426ms ± 1%     400ms ± 1%  -6.16%  (p=0.000 n=10+10)
TimeFormat-8                330ns ± 1%     327ns ± 0%  -0.82%  (p=0.000 n=10+10)

name                     old speed      new speed      delta
Gzip-8                   84.4MB/s ± 0%  84.8MB/s ± 1%  +0.47%  (p=0.001 n=10+9)
JSONDecode-8             37.6MB/s ± 0%  37.4MB/s ± 1%  -0.42%  (p=0.016 n=10+9)
RegexpMatchEasy0_32-8     387MB/s ± 1%   392MB/s ± 0%  +1.06%  (p=0.000 n=9+8)
RegexpMatchMedium_32-8   8.21MB/s ± 1%  8.34MB/s ± 1%  +1.58%  (p=0.000 n=10+9)
Revcomp-8                 597MB/s ± 1%   636MB/s ± 1%  +6.57%  (p=0.000 n=10+10)

Change-Id: Ie37ff91605b76a984a8400dfd1e34f50bf61c864
Reviewed-on: https://go-review.googlesource.com/37290
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
philhofer 2017-02-20 08:43:54 -08:00 committed by Josh Bleecher Snyder
parent 504bc3ed24
commit 379567aad1
3 changed files with 2918 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

161
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -115,6 +115,21 @@
(Const32F [f2i(float64(i2f32(c) * i2f32(d)))])
(Mul64F (Const64F [c]) (Const64F [d])) -> (Const64F [f2i(i2f(c) * i2f(d))])
(And8 (Const8 [c]) (Const8 [d])) -> (Const8 [int64(int8(c&d))])
(And16 (Const16 [c]) (Const16 [d])) -> (Const16 [int64(int16(c&d))])
(And32 (Const32 [c]) (Const32 [d])) -> (Const32 [int64(int32(c&d))])
(And64 (Const64 [c]) (Const64 [d])) -> (Const64 [c&d])
(Or8 (Const8 [c]) (Const8 [d])) -> (Const8 [int64(int8(c|d))])
(Or16 (Const16 [c]) (Const16 [d])) -> (Const16 [int64(int16(c|d))])
(Or32 (Const32 [c]) (Const32 [d])) -> (Const32 [int64(int32(c|d))])
(Or64 (Const64 [c]) (Const64 [d])) -> (Const64 [c|d])
(Xor8 (Const8 [c]) (Const8 [d])) -> (Const8 [int64(int8(c^d))])
(Xor16 (Const16 [c]) (Const16 [d])) -> (Const16 [int64(int16(c^d))])
(Xor32 (Const32 [c]) (Const32 [d])) -> (Const32 [int64(int32(c^d))])
(Xor64 (Const64 [c]) (Const64 [d])) -> (Const64 [c^d])
(Div8 (Const8 [c]) (Const8 [d])) && d != 0 -> (Const8 [int64(int8(c)/int8(d))])
(Div16 (Const16 [c]) (Const16 [d])) && d != 0 -> (Const16 [int64(int16(c)/int16(d))])
(Div32 (Const32 [c]) (Const32 [d])) && d != 0 -> (Const32 [int64(int32(c)/int32(d))])
@ -602,6 +617,10 @@
(Neg16 (Sub16 x y)) -> (Sub16 y x)
(Neg32 (Sub32 x y)) -> (Sub32 y x)
(Neg64 (Sub64 x y)) -> (Sub64 y x)
(Add8 (Const8 [1]) (Com8 x)) -> (Neg8 x)
(Add16 (Const16 [1]) (Com16 x)) -> (Neg16 x)
(Add32 (Const32 [1]) (Com32 x)) -> (Neg32 x)
(Add64 (Const64 [1]) (Com64 x)) -> (Neg64 x)
(And64 x (And64 x y)) -> (And64 x y)
(And32 x (And32 x y)) -> (And32 x y)
@ -1201,6 +1220,148 @@
(Mod64u <t> x (Const64 [c])) && x.Op != OpConst64 && c > 0 && umagicOK(64,c)
-> (Sub64 x (Mul64 <t> (Div64u <t> x (Const64 <t> [c])) (Const64 <t> [c])))
// Reassociate expressions involving
// constants such that constants come first,
// exposing obvious constant-folding opportunities.
// First, re-write (op x (op y z)) to (op (op y z) x) if
// the op is commutative, to reduce the number of subsequent
// matching rules for folding. Then, reassociate
// (op (op y C) x) to (op C (op x y)) or similar, where C
// is constant, which pushes constants to the outside
// of the expression. At that point, any constant-folding
// opportunities should be obvious.
(Add64 x l:(Add64 _ _)) && (x.Op != OpAdd64 && x.Op != OpConst64) -> (Add64 l x)
(Add32 x l:(Add32 _ _)) && (x.Op != OpAdd32 && x.Op != OpConst32) -> (Add32 l x)
(Add16 x l:(Add16 _ _)) && (x.Op != OpAdd16 && x.Op != OpConst16) -> (Add16 l x)
(Add8 x l:(Add8 _ _)) && (x.Op != OpAdd8 && x.Op != OpConst8) -> (Add8 l x)
(And64 x l:(And64 _ _)) && (x.Op != OpAnd64 && x.Op != OpConst64) -> (And64 l x)
(And32 x l:(And32 _ _)) && (x.Op != OpAnd32 && x.Op != OpConst32) -> (And32 l x)
(And16 x l:(And16 _ _)) && (x.Op != OpAnd16 && x.Op != OpConst16) -> (And16 l x)
(And8 x l:(And8 _ _)) && (x.Op != OpAnd8 && x.Op != OpConst8) -> (And8 l x)
(Or64 x l:(Or64 _ _)) && (x.Op != OpOr64 && x.Op != OpConst64) -> (Or64 l x)
(Or32 x l:(Or32 _ _)) && (x.Op != OpOr32 && x.Op != OpConst32) -> (Or32 l x)
(Or16 x l:(Or16 _ _)) && (x.Op != OpOr16 && x.Op != OpConst16) -> (Or16 l x)
(Or8 x l:(Or8 _ _)) && (x.Op != OpOr8 && x.Op != OpConst8) -> (Or8 l x)
(Xor64 x l:(Xor64 _ _)) && (x.Op != OpXor64 && x.Op != OpConst64) -> (Xor64 l x)
(Xor32 x l:(Xor32 _ _)) && (x.Op != OpXor32 && x.Op != OpConst32) -> (Xor32 l x)
(Xor16 x l:(Xor16 _ _)) && (x.Op != OpXor16 && x.Op != OpConst16) -> (Xor16 l x)
(Xor8 x l:(Xor8 _ _)) && (x.Op != OpXor8 && x.Op != OpConst8) -> (Xor8 l x)
(Mul64 x l:(Mul64 _ _)) && (x.Op != OpMul64 && x.Op != OpConst64) -> (Mul64 l x)
(Mul32 x l:(Mul32 _ _)) && (x.Op != OpMul32 && x.Op != OpConst32) -> (Mul32 l x)
(Mul16 x l:(Mul16 _ _)) && (x.Op != OpMul16 && x.Op != OpConst16) -> (Mul16 l x)
(Mul8 x l:(Mul8 _ _)) && (x.Op != OpMul8 && x.Op != OpConst8) -> (Mul8 l x)
// x + (C + z) -> C + (x + z)
(Add64 (Add64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Add64 i (Add64 <t> z x))
(Add32 (Add32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Add32 i (Add32 <t> z x))
(Add16 (Add16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Add16 i (Add16 <t> z x))
(Add8 (Add8 i:(Const8 <t>) z) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Add8 i (Add8 <t> z x))
// x + (C - z) -> C + (x - z)
(Add64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Add64 i (Sub64 <t> x z))
(Add32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Add32 i (Sub32 <t> x z))
(Add16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Add16 i (Sub16 <t> x z))
(Add8 (Sub8 i:(Const8 <t>) z) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Add8 i (Sub8 <t> x z))
(Add64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Add64 i (Sub64 <t> x z))
(Add32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Add32 i (Sub32 <t> x z))
(Add16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Add16 i (Sub16 <t> x z))
(Add8 x (Sub8 i:(Const8 <t>) z)) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Add8 i (Sub8 <t> x z))
// x + (z - C) -> (x + z) - C
(Add64 (Sub64 z i:(Const64 <t>)) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Sub64 (Add64 <t> x z) i)
(Add32 (Sub32 z i:(Const32 <t>)) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Sub32 (Add32 <t> x z) i)
(Add16 (Sub16 z i:(Const16 <t>)) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Sub16 (Add16 <t> x z) i)
(Add8 (Sub8 z i:(Const8 <t>)) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Sub8 (Add8 <t> x z) i)
(Add64 x (Sub64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Sub64 (Add64 <t> x z) i)
(Add32 x (Sub32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Sub32 (Add32 <t> x z) i)
(Add16 x (Sub16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Sub16 (Add16 <t> x z) i)
(Add8 x (Sub8 z i:(Const8 <t>))) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Sub8 (Add8 <t> x z) i)
// x - (C - z) -> x + (z - C) -> (x + z) - C
(Sub64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Sub64 (Add64 <t> x z) i)
(Sub32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Sub32 (Add32 <t> x z) i)
(Sub16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Sub16 (Add16 <t> x z) i)
(Sub8 x (Sub8 i:(Const8 <t>) z)) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Sub8 (Add8 <t> x z) i)
// x - (z - C) -> x + (C - z) -> (x - z) + C
(Sub64 x (Sub64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Add64 i (Sub64 <t> x z))
(Sub32 x (Sub32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Add32 i (Sub32 <t> x z))
(Sub16 x (Sub16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Add16 i (Sub16 <t> x z))
(Sub8 x (Sub8 z i:(Const8 <t>))) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Add8 i (Sub8 <t> x z))
// x & (C & z) -> C & (x & z)
(And64 (And64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (And64 i (And64 <t> z x))
(And32 (And32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (And32 i (And32 <t> z x))
(And16 (And16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (And16 i (And16 <t> z x))
(And8 (And8 i:(Const8 <t>) z) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (And8 i (And8 <t> z x))
// x | (C | z) -> C | (x | z)
(Or64 (Or64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Or64 i (Or64 <t> z x))
(Or32 (Or32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Or32 i (Or32 <t> z x))
(Or16 (Or16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Or16 i (Or16 <t> z x))
(Or8 (Or8 i:(Const8 <t>) z) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Or8 i (Or8 <t> z x))
// x ^ (C ^ z) -> C ^ (x ^ z)
(Xor64 (Xor64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) -> (Xor64 i (Xor64 <t> z x))
(Xor32 (Xor32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) -> (Xor32 i (Xor32 <t> z x))
(Xor16 (Xor16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) -> (Xor16 i (Xor16 <t> z x))
(Xor8 (Xor8 i:(Const8 <t>) z) x) && (z.Op != OpConst8 && x.Op != OpConst8) -> (Xor8 i (Xor8 <t> z x))
// C + (D + x) -> (C + D) + x
(Add64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) -> (Add64 (Const64 <t> [c+d]) x)
(Add32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) -> (Add32 (Const32 <t> [int64(int32(c+d))]) x)
(Add16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) -> (Add16 (Const16 <t> [int64(int16(c+d))]) x)
(Add8 (Const8 <t> [c]) (Add8 (Const8 <t> [d]) x)) -> (Add8 (Const8 <t> [int64(int8(c+d))]) x)
// C + (D - x) -> (C + D) - x
(Add64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) -> (Sub64 (Const64 <t> [c+d]) x)
(Add32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) -> (Sub32 (Const32 <t> [int64(int32(c+d))]) x)
(Add16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) -> (Sub16 (Const16 <t> [int64(int16(c+d))]) x)
(Add8 (Const8 <t> [c]) (Sub8 (Const8 <t> [d]) x)) -> (Sub8 (Const8 <t> [int64(int8(c+d))]) x)
// C + (x - D) -> (C - D) + x
(Add64 (Const64 <t> [c]) (Sub64 x (Const64 <t> [d]))) -> (Add64 (Const64 <t> [c-d]) x)
(Add32 (Const32 <t> [c]) (Sub32 x (Const32 <t> [d]))) -> (Add32 (Const32 <t> [int64(int32(c-d))]) x)
(Add16 (Const16 <t> [c]) (Sub16 x (Const16 <t> [d]))) -> (Add16 (Const16 <t> [int64(int16(c-d))]) x)
(Add8 (Const8 <t> [c]) (Sub8 x (Const8 <t> [d]))) -> (Add8 (Const8 <t> [int64(int8(c-d))]) x)
// C - (x - D) -> (C + D) - x
(Sub64 (Const64 <t> [c]) (Sub64 x (Const64 <t> [d]))) -> (Sub64 (Const64 <t> [c+d]) x)
(Sub32 (Const32 <t> [c]) (Sub32 x (Const32 <t> [d]))) -> (Sub32 (Const32 <t> [int64(int32(c+d))]) x)
(Sub16 (Const16 <t> [c]) (Sub16 x (Const16 <t> [d]))) -> (Sub16 (Const16 <t> [int64(int16(c+d))]) x)
(Sub8 (Const8 <t> [c]) (Sub8 x (Const8 <t> [d]))) -> (Sub8 (Const8 <t> [int64(int8(c+d))]) x)
// C - (D - x) -> (C - D) + x
(Sub64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) -> (Add64 (Const64 <t> [c-d]) x)
(Sub32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) -> (Add32 (Const32 <t> [int64(int32(c-d))]) x)
(Sub16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) -> (Add16 (Const16 <t> [int64(int16(c-d))]) x)
(Sub8 (Const8 <t> [c]) (Sub8 (Const8 <t> [d]) x)) -> (Add8 (Const8 <t> [int64(int8(c-d))]) x)
// C & (D & x) -> (C & D) & x
(And64 (Const64 <t> [c]) (And64 (Const64 <t> [d]) x)) -> (And64 (Const64 <t> [c&d]) x)
(And32 (Const32 <t> [c]) (And32 (Const32 <t> [d]) x)) -> (And32 (Const32 <t> [int64(int32(c&d))]) x)
(And16 (Const16 <t> [c]) (And16 (Const16 <t> [d]) x)) -> (And16 (Const16 <t> [int64(int16(c&d))]) x)
(And8 (Const8 <t> [c]) (And8 (Const8 <t> [d]) x)) -> (And8 (Const8 <t> [int64(int8(c&d))]) x)
// C | (D | x) -> (C | D) | x
(Or64 (Const64 <t> [c]) (Or64 (Const64 <t> [d]) x)) -> (Or64 (Const64 <t> [c|d]) x)
(Or32 (Const32 <t> [c]) (Or32 (Const32 <t> [d]) x)) -> (Or32 (Const32 <t> [int64(int32(c|d))]) x)
(Or16 (Const16 <t> [c]) (Or16 (Const16 <t> [d]) x)) -> (Or16 (Const16 <t> [int64(int16(c|d))]) x)
(Or8 (Const8 <t> [c]) (Or8 (Const8 <t> [d]) x)) -> (Or8 (Const8 <t> [int64(int8(c|d))]) x)
// C ^ (D ^ x) -> (C ^ D) ^ x
(Xor64 (Const64 <t> [c]) (Xor64 (Const64 <t> [d]) x)) -> (Xor64 (Const64 <t> [c^d]) x)
(Xor32 (Const32 <t> [c]) (Xor32 (Const32 <t> [d]) x)) -> (Xor32 (Const32 <t> [int64(int32(c^d))]) x)
(Xor16 (Const16 <t> [c]) (Xor16 (Const16 <t> [d]) x)) -> (Xor16 (Const16 <t> [int64(int16(c^d))]) x)
(Xor8 (Const8 <t> [c]) (Xor8 (Const8 <t> [d]) x)) -> (Xor8 (Const8 <t> [int64(int8(c^d))]) x)
// C * (D * x) = (C * D) * x
(Mul64 (Const64 <t> [c]) (Mul64 (Const64 <t> [d]) x)) -> (Mul64 (Const64 <t> [c*d]) x)
(Mul32 (Const32 <t> [c]) (Mul32 (Const32 <t> [d]) x)) -> (Mul32 (Const32 <t> [int64(int32(c*d))]) x)
(Mul16 (Const16 <t> [c]) (Mul16 (Const16 <t> [d]) x)) -> (Mul16 (Const16 <t> [int64(int16(c*d))]) x)
(Mul8 (Const8 <t> [c]) (Mul8 (Const8 <t> [d]) x)) -> (Mul8 (Const8 <t> [int64(int8(c*d))]) x)
// floating point optimizations
(Add32F x (Const32F [0])) -> x
(Add32F (Const32F [0]) x) -> x

2756
src/cmd/compile/internal/ssa/rewritegeneric.go
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File diff suppressed because it is too large Load Diff

2
test/loopbce.go
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@ -197,7 +197,7 @@ func k4(a [100]int) [100]int {
func k5(a [100]int) [100]int {
max := (1 << 63) - 1
for i := max - 50; i < max; i++ { // ERROR "Induction variable with minimum 9223372036854775757 and increment 1$"
a[i-max+50] = i
a[i-max+50] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 50$"
a[i-(max-70)] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 70$"
}
return a