cmd/compile: possible issue in optimization of -(c+-x) #31888
Labels
FrozenDueToAge
NeedsInvestigation
Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.
Milestone
Comments
josharian
added
the
NeedsInvestigation
|
That's why the restriction is there, so that we don't generate an |
|
Ah! Thanks. |
|
Change https://golang.org/cl/175778 mentions this issue: |
gopherbot
pushed a commit
that referenced
this issue
Aug 29, 2019
This is a grab-bag of minor optimizations. While we're here, document the c != -(1<<31) constraints better (#31888). file before after Δ % go 14669924 14665828 -4096 -0.028% asm 4867088 4858896 -8192 -0.168% compile 23988320 23984224 -4096 -0.017% cover 5210856 5206760 -4096 -0.079% link 6084376 6080280 -4096 -0.067% total 132181084 132156508 -24576 -0.019% file before after Δ % archive/tar.a 516708 516702 -6 -0.001% bufio.a 182200 181974 -226 -0.124% bytes.a 217624 216890 -734 -0.337% cmd/compile/internal/gc.a 8865412 8865228 -184 -0.002% cmd/compile/internal/ssa.a 29921002 29933976 +12974 +0.043% cmd/go/internal/modfetch/codehost.a 530602 530430 -172 -0.032% cmd/go/internal/modfetch.a 679664 679578 -86 -0.013% cmd/go/internal/modfile.a 411102 410928 -174 -0.042% cmd/go/internal/test.a 315218 315126 -92 -0.029% cmd/go/internal/tlog.a 183242 183256 +14 +0.008% cmd/go/internal/txtar.a 23148 23060 -88 -0.380% cmd/internal/bio.a 132064 132060 -4 -0.003% cmd/internal/buildid.a 107174 107172 -2 -0.002% cmd/internal/edit.a 33208 33354 +146 +0.440% cmd/internal/obj/arm.a 416488 416432 -56 -0.013% cmd/internal/obj/arm64.a 2772626 2772622 -4 -0.000% cmd/internal/obj/x86.a 923186 923114 -72 -0.008% cmd/internal/obj.a 679834 679836 +2 +0.000% cmd/internal/objfile.a 358374 358372 -2 -0.001% cmd/internal/test2json.a 67482 67434 -48 -0.071% cmd/link/internal/ld.a 2836280 2836110 -170 -0.006% cmd/link/internal/loadpe.a 148234 147736 -498 -0.336% cmd/link/internal/objfile.a 144534 144434 -100 -0.069% cmd/link/internal/ppc64.a 170876 170382 -494 -0.289% cmd/vendor/github.com/google/pprof/internal/elfexec.a 49896 49892 -4 -0.008% cmd/vendor/github.com/google/pprof/internal/graph.a 437478 437404 -74 -0.017% cmd/vendor/github.com/google/pprof/profile.a 902040 902044 +4 +0.000% cmd/vendor/github.com/ianlancetaylor/demangle.a 1217856 1217854 -2 -0.000% cmd/vendor/golang.org/x/arch/x86/x86asm.a 561332 560684 -648 -0.115% cmd/vendor/golang.org/x/crypto/ssh/terminal.a 153788 153784 -4 -0.003% cmd/vendor/golang.org/x/sys/unix.a 1043894 1043814 -80 -0.008% cmd/vendor/golang.org/x/tools/go/analysis/passes/printf.a 288458 288414 -44 -0.015% compress/flate.a 369024 368132 -892 -0.242% crypto/aes.a 109058 108968 -90 -0.083% crypto/cipher.a 150410 150544 +134 +0.089% crypto/elliptic.a 323572 323758 +186 +0.057% crypto/md5.a 50868 50788 -80 -0.157% crypto/rsa.a 195292 195214 -78 -0.040% crypto/sha1.a 70936 70858 -78 -0.110% crypto/sha256.a 75316 75236 -80 -0.106% crypto/sha512.a 84846 84768 -78 -0.092% crypto/subtle.a 6520 6514 -6 -0.092% crypto/tls.a 1654916 1654852 -64 -0.004% crypto/x509.a 888674 888638 -36 -0.004% database/sql.a 730280 730198 -82 -0.011% debug/gosym.a 184936 184862 -74 -0.040% debug/macho.a 272138 272136 -2 -0.001% debug/plan9obj.a 78444 78368 -76 -0.097% encoding/base64.a 82126 81882 -244 -0.297% encoding/binary.a 187196 187150 -46 -0.025% encoding/gob.a 897868 897870 +2 +0.000% encoding/json.a 659934 659832 -102 -0.015% encoding/pem.a 59138 58870 -268 -0.453% encoding/xml.a 694054 693300 -754 -0.109% fmt.a 484518 484196 -322 -0.066% go/format.a 33962 33994 +32 +0.094% go/printer.a 437132 437134 +2 +0.000% go/scanner.a 141774 141772 -2 -0.001% go/token.a 125130 125126 -4 -0.003% go/types.a 2192086 2191994 -92 -0.004% html/template.a 599038 598770 -268 -0.045% html.a 184842 184710 -132 -0.071% image/draw.a 129592 129238 -354 -0.273% image/gif.a 171824 171716 -108 -0.063% image/internal/imageutil.a 20282 19272 -1010 -4.980% image/jpeg.a 275608 275114 -494 -0.179% image/png.a 343416 343620 +204 +0.059% image.a 362244 362210 -34 -0.009% index/suffixarray.a 113040 112954 -86 -0.076% internal/trace.a 518972 518838 -134 -0.026% math/big.a 1012670 1012354 -316 -0.031% math.a 219338 219334 -4 -0.002% mime/multipart.a 178854 178502 -352 -0.197% mime/quotedprintable.a 49226 48936 -290 -0.589% net/http/cgi.a 172328 172324 -4 -0.002% net/http.a 4000180 3999732 -448 -0.011% net.a 1858330 1858252 -78 -0.004% path/filepath.a 107496 107498 +2 +0.002% reflect.a 1439776 1439994 +218 +0.015% regexp/syntax.a 459430 459432 +2 +0.000% regexp.a 416394 416400 +6 +0.001% runtime/debug.a 42106 42100 -6 -0.014% runtime/pprof/internal/profile.a 608718 608720 +2 +0.000% runtime/pprof.a 355474 355476 +2 +0.001% runtime.a 3555748 3555796 +48 +0.001% strconv.a 294432 294410 -22 -0.007% strings.a 292148 292090 -58 -0.020% syscall.a 859682 859470 -212 -0.025% text/tabwriter.a 65614 65148 -466 -0.710% vendor/golang.org/x/crypto/chacha20poly1305.a 126736 126728 -8 -0.006% vendor/golang.org/x/crypto/cryptobyte.a 269112 269114 +2 +0.001% vendor/golang.org/x/crypto/internal/chacha20.a 61842 61262 -580 -0.938% vendor/golang.org/x/crypto/poly1305.a 47410 47404 -6 -0.013% vendor/golang.org/x/net/dns/dnsmessage.a 628700 628012 -688 -0.109% vendor/golang.org/x/net/idna.a 237678 237826 +148 +0.062% vendor/golang.org/x/net/route.a 187852 187458 -394 -0.210% vendor/golang.org/x/sys/unix.a 1022426 1022348 -78 -0.008% vendor/golang.org/x/text/transform.a 117954 118104 +150 +0.127% vendor/golang.org/x/text/unicode/bidi.a 291398 291404 +6 +0.002% vendor/golang.org/x/text/unicode/norm.a 534640 534540 -100 -0.019% total 128945190 128945128 -62 -0.000% Change-Id: I346dc31356d5ef7774b824cf202169610bd26432 Reviewed-on: https://go-review.googlesource.com/c/go/+/175778 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
tomocy
pushed a commit
to tomocy/go
that referenced
this issue
Sep 1, 2019
This is a grab-bag of minor optimizations. While we're here, document the c != -(1<<31) constraints better (golang#31888). file before after Δ % go 14669924 14665828 -4096 -0.028% asm 4867088 4858896 -8192 -0.168% compile 23988320 23984224 -4096 -0.017% cover 5210856 5206760 -4096 -0.079% link 6084376 6080280 -4096 -0.067% total 132181084 132156508 -24576 -0.019% file before after Δ % archive/tar.a 516708 516702 -6 -0.001% bufio.a 182200 181974 -226 -0.124% bytes.a 217624 216890 -734 -0.337% cmd/compile/internal/gc.a 8865412 8865228 -184 -0.002% cmd/compile/internal/ssa.a 29921002 29933976 +12974 +0.043% cmd/go/internal/modfetch/codehost.a 530602 530430 -172 -0.032% cmd/go/internal/modfetch.a 679664 679578 -86 -0.013% cmd/go/internal/modfile.a 411102 410928 -174 -0.042% cmd/go/internal/test.a 315218 315126 -92 -0.029% cmd/go/internal/tlog.a 183242 183256 +14 +0.008% cmd/go/internal/txtar.a 23148 23060 -88 -0.380% cmd/internal/bio.a 132064 132060 -4 -0.003% cmd/internal/buildid.a 107174 107172 -2 -0.002% cmd/internal/edit.a 33208 33354 +146 +0.440% cmd/internal/obj/arm.a 416488 416432 -56 -0.013% cmd/internal/obj/arm64.a 2772626 2772622 -4 -0.000% cmd/internal/obj/x86.a 923186 923114 -72 -0.008% cmd/internal/obj.a 679834 679836 +2 +0.000% cmd/internal/objfile.a 358374 358372 -2 -0.001% cmd/internal/test2json.a 67482 67434 -48 -0.071% cmd/link/internal/ld.a 2836280 2836110 -170 -0.006% cmd/link/internal/loadpe.a 148234 147736 -498 -0.336% cmd/link/internal/objfile.a 144534 144434 -100 -0.069% cmd/link/internal/ppc64.a 170876 170382 -494 -0.289% cmd/vendor/github.com/google/pprof/internal/elfexec.a 49896 49892 -4 -0.008% cmd/vendor/github.com/google/pprof/internal/graph.a 437478 437404 -74 -0.017% cmd/vendor/github.com/google/pprof/profile.a 902040 902044 +4 +0.000% cmd/vendor/github.com/ianlancetaylor/demangle.a 1217856 1217854 -2 -0.000% cmd/vendor/golang.org/x/arch/x86/x86asm.a 561332 560684 -648 -0.115% cmd/vendor/golang.org/x/crypto/ssh/terminal.a 153788 153784 -4 -0.003% cmd/vendor/golang.org/x/sys/unix.a 1043894 1043814 -80 -0.008% cmd/vendor/golang.org/x/tools/go/analysis/passes/printf.a 288458 288414 -44 -0.015% compress/flate.a 369024 368132 -892 -0.242% crypto/aes.a 109058 108968 -90 -0.083% crypto/cipher.a 150410 150544 +134 +0.089% crypto/elliptic.a 323572 323758 +186 +0.057% crypto/md5.a 50868 50788 -80 -0.157% crypto/rsa.a 195292 195214 -78 -0.040% crypto/sha1.a 70936 70858 -78 -0.110% crypto/sha256.a 75316 75236 -80 -0.106% crypto/sha512.a 84846 84768 -78 -0.092% crypto/subtle.a 6520 6514 -6 -0.092% crypto/tls.a 1654916 1654852 -64 -0.004% crypto/x509.a 888674 888638 -36 -0.004% database/sql.a 730280 730198 -82 -0.011% debug/gosym.a 184936 184862 -74 -0.040% debug/macho.a 272138 272136 -2 -0.001% debug/plan9obj.a 78444 78368 -76 -0.097% encoding/base64.a 82126 81882 -244 -0.297% encoding/binary.a 187196 187150 -46 -0.025% encoding/gob.a 897868 897870 +2 +0.000% encoding/json.a 659934 659832 -102 -0.015% encoding/pem.a 59138 58870 -268 -0.453% encoding/xml.a 694054 693300 -754 -0.109% fmt.a 484518 484196 -322 -0.066% go/format.a 33962 33994 +32 +0.094% go/printer.a 437132 437134 +2 +0.000% go/scanner.a 141774 141772 -2 -0.001% go/token.a 125130 125126 -4 -0.003% go/types.a 2192086 2191994 -92 -0.004% html/template.a 599038 598770 -268 -0.045% html.a 184842 184710 -132 -0.071% image/draw.a 129592 129238 -354 -0.273% image/gif.a 171824 171716 -108 -0.063% image/internal/imageutil.a 20282 19272 -1010 -4.980% image/jpeg.a 275608 275114 -494 -0.179% image/png.a 343416 343620 +204 +0.059% image.a 362244 362210 -34 -0.009% index/suffixarray.a 113040 112954 -86 -0.076% internal/trace.a 518972 518838 -134 -0.026% math/big.a 1012670 1012354 -316 -0.031% math.a 219338 219334 -4 -0.002% mime/multipart.a 178854 178502 -352 -0.197% mime/quotedprintable.a 49226 48936 -290 -0.589% net/http/cgi.a 172328 172324 -4 -0.002% net/http.a 4000180 3999732 -448 -0.011% net.a 1858330 1858252 -78 -0.004% path/filepath.a 107496 107498 +2 +0.002% reflect.a 1439776 1439994 +218 +0.015% regexp/syntax.a 459430 459432 +2 +0.000% regexp.a 416394 416400 +6 +0.001% runtime/debug.a 42106 42100 -6 -0.014% runtime/pprof/internal/profile.a 608718 608720 +2 +0.000% runtime/pprof.a 355474 355476 +2 +0.001% runtime.a 3555748 3555796 +48 +0.001% strconv.a 294432 294410 -22 -0.007% strings.a 292148 292090 -58 -0.020% syscall.a 859682 859470 -212 -0.025% text/tabwriter.a 65614 65148 -466 -0.710% vendor/golang.org/x/crypto/chacha20poly1305.a 126736 126728 -8 -0.006% vendor/golang.org/x/crypto/cryptobyte.a 269112 269114 +2 +0.001% vendor/golang.org/x/crypto/internal/chacha20.a 61842 61262 -580 -0.938% vendor/golang.org/x/crypto/poly1305.a 47410 47404 -6 -0.013% vendor/golang.org/x/net/dns/dnsmessage.a 628700 628012 -688 -0.109% vendor/golang.org/x/net/idna.a 237678 237826 +148 +0.062% vendor/golang.org/x/net/route.a 187852 187458 -394 -0.210% vendor/golang.org/x/sys/unix.a 1022426 1022348 -78 -0.008% vendor/golang.org/x/text/transform.a 117954 118104 +150 +0.127% vendor/golang.org/x/text/unicode/bidi.a 291398 291404 +6 +0.002% vendor/golang.org/x/text/unicode/norm.a 534640 534540 -100 -0.019% total 128945190 128945128 -62 -0.000% Change-Id: I346dc31356d5ef7774b824cf202169610bd26432 Reviewed-on: https://go-review.googlesource.com/c/go/+/175778 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
t4n6a1ka
pushed a commit
to t4n6a1ka/go
that referenced
this issue
Sep 5, 2019
This is a grab-bag of minor optimizations. While we're here, document the c != -(1<<31) constraints better (golang#31888). file before after Δ % go 14669924 14665828 -4096 -0.028% asm 4867088 4858896 -8192 -0.168% compile 23988320 23984224 -4096 -0.017% cover 5210856 5206760 -4096 -0.079% link 6084376 6080280 -4096 -0.067% total 132181084 132156508 -24576 -0.019% file before after Δ % archive/tar.a 516708 516702 -6 -0.001% bufio.a 182200 181974 -226 -0.124% bytes.a 217624 216890 -734 -0.337% cmd/compile/internal/gc.a 8865412 8865228 -184 -0.002% cmd/compile/internal/ssa.a 29921002 29933976 +12974 +0.043% cmd/go/internal/modfetch/codehost.a 530602 530430 -172 -0.032% cmd/go/internal/modfetch.a 679664 679578 -86 -0.013% cmd/go/internal/modfile.a 411102 410928 -174 -0.042% cmd/go/internal/test.a 315218 315126 -92 -0.029% cmd/go/internal/tlog.a 183242 183256 +14 +0.008% cmd/go/internal/txtar.a 23148 23060 -88 -0.380% cmd/internal/bio.a 132064 132060 -4 -0.003% cmd/internal/buildid.a 107174 107172 -2 -0.002% cmd/internal/edit.a 33208 33354 +146 +0.440% cmd/internal/obj/arm.a 416488 416432 -56 -0.013% cmd/internal/obj/arm64.a 2772626 2772622 -4 -0.000% cmd/internal/obj/x86.a 923186 923114 -72 -0.008% cmd/internal/obj.a 679834 679836 +2 +0.000% cmd/internal/objfile.a 358374 358372 -2 -0.001% cmd/internal/test2json.a 67482 67434 -48 -0.071% cmd/link/internal/ld.a 2836280 2836110 -170 -0.006% cmd/link/internal/loadpe.a 148234 147736 -498 -0.336% cmd/link/internal/objfile.a 144534 144434 -100 -0.069% cmd/link/internal/ppc64.a 170876 170382 -494 -0.289% cmd/vendor/github.com/google/pprof/internal/elfexec.a 49896 49892 -4 -0.008% cmd/vendor/github.com/google/pprof/internal/graph.a 437478 437404 -74 -0.017% cmd/vendor/github.com/google/pprof/profile.a 902040 902044 +4 +0.000% cmd/vendor/github.com/ianlancetaylor/demangle.a 1217856 1217854 -2 -0.000% cmd/vendor/golang.org/x/arch/x86/x86asm.a 561332 560684 -648 -0.115% cmd/vendor/golang.org/x/crypto/ssh/terminal.a 153788 153784 -4 -0.003% cmd/vendor/golang.org/x/sys/unix.a 1043894 1043814 -80 -0.008% cmd/vendor/golang.org/x/tools/go/analysis/passes/printf.a 288458 288414 -44 -0.015% compress/flate.a 369024 368132 -892 -0.242% crypto/aes.a 109058 108968 -90 -0.083% crypto/cipher.a 150410 150544 +134 +0.089% crypto/elliptic.a 323572 323758 +186 +0.057% crypto/md5.a 50868 50788 -80 -0.157% crypto/rsa.a 195292 195214 -78 -0.040% crypto/sha1.a 70936 70858 -78 -0.110% crypto/sha256.a 75316 75236 -80 -0.106% crypto/sha512.a 84846 84768 -78 -0.092% crypto/subtle.a 6520 6514 -6 -0.092% crypto/tls.a 1654916 1654852 -64 -0.004% crypto/x509.a 888674 888638 -36 -0.004% database/sql.a 730280 730198 -82 -0.011% debug/gosym.a 184936 184862 -74 -0.040% debug/macho.a 272138 272136 -2 -0.001% debug/plan9obj.a 78444 78368 -76 -0.097% encoding/base64.a 82126 81882 -244 -0.297% encoding/binary.a 187196 187150 -46 -0.025% encoding/gob.a 897868 897870 +2 +0.000% encoding/json.a 659934 659832 -102 -0.015% encoding/pem.a 59138 58870 -268 -0.453% encoding/xml.a 694054 693300 -754 -0.109% fmt.a 484518 484196 -322 -0.066% go/format.a 33962 33994 +32 +0.094% go/printer.a 437132 437134 +2 +0.000% go/scanner.a 141774 141772 -2 -0.001% go/token.a 125130 125126 -4 -0.003% go/types.a 2192086 2191994 -92 -0.004% html/template.a 599038 598770 -268 -0.045% html.a 184842 184710 -132 -0.071% image/draw.a 129592 129238 -354 -0.273% image/gif.a 171824 171716 -108 -0.063% image/internal/imageutil.a 20282 19272 -1010 -4.980% image/jpeg.a 275608 275114 -494 -0.179% image/png.a 343416 343620 +204 +0.059% image.a 362244 362210 -34 -0.009% index/suffixarray.a 113040 112954 -86 -0.076% internal/trace.a 518972 518838 -134 -0.026% math/big.a 1012670 1012354 -316 -0.031% math.a 219338 219334 -4 -0.002% mime/multipart.a 178854 178502 -352 -0.197% mime/quotedprintable.a 49226 48936 -290 -0.589% net/http/cgi.a 172328 172324 -4 -0.002% net/http.a 4000180 3999732 -448 -0.011% net.a 1858330 1858252 -78 -0.004% path/filepath.a 107496 107498 +2 +0.002% reflect.a 1439776 1439994 +218 +0.015% regexp/syntax.a 459430 459432 +2 +0.000% regexp.a 416394 416400 +6 +0.001% runtime/debug.a 42106 42100 -6 -0.014% runtime/pprof/internal/profile.a 608718 608720 +2 +0.000% runtime/pprof.a 355474 355476 +2 +0.001% runtime.a 3555748 3555796 +48 +0.001% strconv.a 294432 294410 -22 -0.007% strings.a 292148 292090 -58 -0.020% syscall.a 859682 859470 -212 -0.025% text/tabwriter.a 65614 65148 -466 -0.710% vendor/golang.org/x/crypto/chacha20poly1305.a 126736 126728 -8 -0.006% vendor/golang.org/x/crypto/cryptobyte.a 269112 269114 +2 +0.001% vendor/golang.org/x/crypto/internal/chacha20.a 61842 61262 -580 -0.938% vendor/golang.org/x/crypto/poly1305.a 47410 47404 -6 -0.013% vendor/golang.org/x/net/dns/dnsmessage.a 628700 628012 -688 -0.109% vendor/golang.org/x/net/idna.a 237678 237826 +148 +0.062% vendor/golang.org/x/net/route.a 187852 187458 -394 -0.210% vendor/golang.org/x/sys/unix.a 1022426 1022348 -78 -0.008% vendor/golang.org/x/text/transform.a 117954 118104 +150 +0.127% vendor/golang.org/x/text/unicode/bidi.a 291398 291404 +6 +0.002% vendor/golang.org/x/text/unicode/norm.a 534640 534540 -100 -0.019% total 128945190 128945128 -62 -0.000% Change-Id: I346dc31356d5ef7774b824cf202169610bd26432 Reviewed-on: https://go-review.googlesource.com/c/go/+/175778 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
amd64.rules contains this rule:
It was added in https://go-review.googlesource.com/c/go/+/38311/.
I don't understand the constraint
c != -(1<<31): Why it is necessary at all, and if it is necessary, why it isn't say-(1<<63). If it does need to be-(1<<63), then we may be generating bad code. As such, tentatively marking Go 1.13.cc @randall77
The text was updated successfully, but these errors were encountered: