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cmd/compile: optimize unsigned comparisons to 0/1 on amd64
Plus a bonus optimization I noticed while working on this. There are no functions (besides the rewrite rules) whose text size increases as a result of this change. Updates #21439 The following per-package text size stats were generated by parsing the output of compiling with -S and summing the function size reported on the STEXT line. This gives a far more accurate picture of the impact on generated code than merely looking at the object file size changes or the resulting binary size changes. The latter are below, for reference. file before after Δ % runtime.s 477257 476417 -840 -0.176% math.s 35985 35976 -9 -0.025% vendor/golang.org/x/net/dns/dnsmessage.s 87314 87232 -82 -0.094% debug/dwarf.s 108444 108432 -12 -0.011% regexp.s 64535 64467 -68 -0.105% internal/xcoff.s 23175 22945 -230 -0.992% cmd/vendor/golang.org/x/arch/arm/armasm.s 45263 45260 -3 -0.007% cmd/vendor/golang.org/x/arch/arm64/arm64asm.s 118140 118135 -5 -0.004% cmd/internal/obj/arm64.s 151502 151498 -4 -0.003% cmd/compile/internal/ssa.s 6061483 6063120 +1637 +0.027% total 9321728 9322112 +384 +0.004% file before after Δ % go 15188916 15184820 -4096 -0.027% addr2line 4315984 4311888 -4096 -0.095% cgo 4836088 4831992 -4096 -0.085% compile 24506008 24493720 -12288 -0.050% doc 4680952 4676856 -4096 -0.088% link 6605336 6601240 -4096 -0.062% pprof 14776756 14772660 -4096 -0.028% total 135250956 135214092 -36864 -0.027% Change-Id: I1243a098a08db452f7d1eb0998e241c9b199e2b4 Reviewed-on: https://go-review.googlesource.com/c/go/+/213058 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Josh Bleecher Snyder
parent
117826903a
commit
18053b7131
@ -567,6 +567,12 @@
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(NE (TESTB (SETAE cmp) (SETAE cmp)) yes no) -> (UGE cmp yes no)
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(NE (TESTB (SETO cmp) (SETO cmp)) yes no) -> (OS cmp yes no)
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// Unsigned comparisons to 0/1
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(ULT (TEST(Q|L|W|B) x x) yes no) -> (First no yes)
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(UGE (TEST(Q|L|W|B) x x) yes no) -> (First yes no)
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(SETB (TEST(Q|L|W|B) x x)) -> (ConstBool [0])
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(SETAE (TEST(Q|L|W|B) x x)) -> (ConstBool [1])
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// Recognize bit tests: a&(1<<b) != 0 for b suitably bounded
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// Note that BTx instructions use the carry bit, so we need to convert tests for zero flag
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// into tests for carry flags.
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@ -1311,6 +1317,8 @@
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(CMPWconst (ANDLconst _ [m]) [n]) && 0 <= int16(m) && int16(m) < int16(n) -> (FlagLT_ULT)
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(CMPBconst (ANDLconst _ [m]) [n]) && 0 <= int8(m) && int8(m) < int8(n) -> (FlagLT_ULT)
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(TEST(Q|L)const [c] (MOV(Q|L)const [c])) -> (FlagEQ)
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// TODO: DIVxU also.
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// Absorb flag constants into SBB ops.
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@ -27249,6 +27249,62 @@ func rewriteValueAMD64_OpAMD64SETA(v *Value) bool {
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}
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func rewriteValueAMD64_OpAMD64SETAE(v *Value) bool {
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v_0 := v.Args[0]
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// match: (SETAE (TESTQ x x))
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// result: (ConstBool [1])
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for {
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if v_0.Op != OpAMD64TESTQ {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 1
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return true
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}
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// match: (SETAE (TESTL x x))
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// result: (ConstBool [1])
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for {
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if v_0.Op != OpAMD64TESTL {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 1
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return true
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}
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// match: (SETAE (TESTW x x))
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// result: (ConstBool [1])
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for {
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if v_0.Op != OpAMD64TESTW {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 1
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return true
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}
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// match: (SETAE (TESTB x x))
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// result: (ConstBool [1])
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for {
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if v_0.Op != OpAMD64TESTB {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 1
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return true
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}
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// match: (SETAE (InvertFlags x))
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// result: (SETBE x)
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for {
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@ -27666,6 +27722,62 @@ func rewriteValueAMD64_OpAMD64SETAstore(v *Value) bool {
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}
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func rewriteValueAMD64_OpAMD64SETB(v *Value) bool {
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v_0 := v.Args[0]
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// match: (SETB (TESTQ x x))
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// result: (ConstBool [0])
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for {
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if v_0.Op != OpAMD64TESTQ {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 0
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return true
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}
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// match: (SETB (TESTL x x))
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// result: (ConstBool [0])
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for {
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if v_0.Op != OpAMD64TESTL {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 0
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return true
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}
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// match: (SETB (TESTW x x))
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// result: (ConstBool [0])
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for {
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if v_0.Op != OpAMD64TESTW {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 0
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return true
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}
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// match: (SETB (TESTB x x))
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// result: (ConstBool [0])
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for {
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if v_0.Op != OpAMD64TESTB {
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break
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}
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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v.reset(OpConstBool)
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v.AuxInt = 0
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return true
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}
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// match: (SETB (InvertFlags x))
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// result: (SETA x)
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for {
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@ -33171,6 +33283,16 @@ func rewriteValueAMD64_OpAMD64TESTL(v *Value) bool {
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}
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func rewriteValueAMD64_OpAMD64TESTLconst(v *Value) bool {
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v_0 := v.Args[0]
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// match: (TESTLconst [c] (MOVLconst [c]))
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// result: (FlagEQ)
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for {
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c := v.AuxInt
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if v_0.Op != OpAMD64MOVLconst || v_0.AuxInt != c {
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break
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}
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v.reset(OpAMD64FlagEQ)
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return true
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}
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// match: (TESTLconst [-1] x)
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// cond: x.Op != OpAMD64MOVLconst
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// result: (TESTL x x)
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@ -33246,6 +33368,16 @@ func rewriteValueAMD64_OpAMD64TESTQ(v *Value) bool {
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}
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func rewriteValueAMD64_OpAMD64TESTQconst(v *Value) bool {
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v_0 := v.Args[0]
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// match: (TESTQconst [c] (MOVQconst [c]))
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// result: (FlagEQ)
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for {
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c := v.AuxInt
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if v_0.Op != OpAMD64MOVQconst || v_0.AuxInt != c {
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break
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}
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v.reset(OpAMD64FlagEQ)
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return true
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}
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// match: (TESTQconst [-1] x)
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// cond: x.Op != OpAMD64MOVQconst
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// result: (TESTQ x x)
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@ -41959,6 +42091,50 @@ func rewriteBlockAMD64(b *Block) bool {
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return true
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}
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case BlockAMD64UGE:
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// match: (UGE (TESTQ x x) yes no)
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// result: (First yes no)
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for b.Controls[0].Op == OpAMD64TESTQ {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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return true
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}
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// match: (UGE (TESTL x x) yes no)
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// result: (First yes no)
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for b.Controls[0].Op == OpAMD64TESTL {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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return true
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}
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// match: (UGE (TESTW x x) yes no)
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// result: (First yes no)
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for b.Controls[0].Op == OpAMD64TESTW {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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return true
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}
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// match: (UGE (TESTB x x) yes no)
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// result: (First yes no)
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for b.Controls[0].Op == OpAMD64TESTB {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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return true
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}
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// match: (UGE (InvertFlags cmp) yes no)
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// result: (ULE cmp yes no)
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for b.Controls[0].Op == OpAMD64InvertFlags {
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@ -42086,6 +42262,54 @@ func rewriteBlockAMD64(b *Block) bool {
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return true
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}
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case BlockAMD64ULT:
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// match: (ULT (TESTQ x x) yes no)
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// result: (First no yes)
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for b.Controls[0].Op == OpAMD64TESTQ {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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b.swapSuccessors()
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return true
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}
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// match: (ULT (TESTL x x) yes no)
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// result: (First no yes)
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for b.Controls[0].Op == OpAMD64TESTL {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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b.swapSuccessors()
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return true
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}
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// match: (ULT (TESTW x x) yes no)
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// result: (First no yes)
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for b.Controls[0].Op == OpAMD64TESTW {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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b.swapSuccessors()
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return true
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}
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// match: (ULT (TESTB x x) yes no)
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// result: (First no yes)
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for b.Controls[0].Op == OpAMD64TESTB {
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v_0 := b.Controls[0]
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x := v_0.Args[1]
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if x != v_0.Args[0] {
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break
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}
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b.Reset(BlockFirst)
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b.swapSuccessors()
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return true
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}
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// match: (ULT (InvertFlags cmp) yes no)
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// result: (UGT cmp yes no)
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for b.Controls[0].Op == OpAMD64InvertFlags {
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