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| author | Cherry Zhang <cherryyz@google.com> | 2017-08-18 08:37:58 -0400 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2017-08-18 17:12:14 +0000 |
| commit | 99fe3f8c63c20d675b0237665a535a8ad9783de4 (patch) | |
| tree | d85092714c2390c3c235123394b0cdeed36bfb1c /src/bytes/buffer.go | |
| parent | 839b28246f7ec04b6d5a8d747a84d6c8bb1c33ef (diff) | |
| download | go-99fe3f8c63c20d675b0237665a535a8ad9783de4.tar.xz | |
cmd/compile: add rules handling unsigned div/mod by constant 1<<63
Normally 64-bit div/mod is turned into runtime calls on 32-bit
arch, but the front end leaves power-of-two constant division
and hopes the SSA backend turns into a shift or AND. The SSA rule is
(Mod64u <t> n (Const64 [c])) && isPowerOfTwo(c) -> (And64 n (Const64 <t> [c-1]))
But isPowerOfTwo returns true only for positive int64, which leaves
out 1<<63 unhandled. Add a special case for 1<<63.
Fixes #21517.
Change-Id: I02d27dc7177d4af0ee8d7f5533714edecddf8c95
Reviewed-on: https://go-review.googlesource.com/56890
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/bytes/buffer.go')
0 files changed, 0 insertions, 0 deletions