diff options
| author | David Chase <drchase@google.com> | 2024-02-29 15:02:44 -0500 |
|---|---|---|
| committer | David Chase <drchase@google.com> | 2024-03-02 14:01:52 +0000 |
| commit | 6f5d77454e31be8af11a7e2bcda36d200fda07c5 (patch) | |
| tree | 8094b7881f1303dca31e0e3d3a8674f055f085c2 /src | |
| parent | b5a64ba62eafe5dee13562091ca03aef6cac87b6 (diff) | |
| download | go-6f5d77454e31be8af11a7e2bcda36d200fda07c5.tar.xz | |
cmd/compile: add 0-sized-value simplification to copyelim
The problem was caused by faulty handling of unSSA-able
operations on zero-sized data in expand calls, but there
is no point to operations on zero-sized data. This CL adds
a simplify step to the first place in SSA where all values
are processed and replaces anything producing a 0-sized
struct/array with the corresponding Struct/Array Make0
operation (of the appropriate type).
I attempted not generating them in ssagen, but that was a
larger change, and also had bugs. This is simple and obvious.
The only question is whether it would be worthwhile to do it
earlier (in numberlines or phielem).
Fixes #65808.
Change-Id: I0a596b3d272798015e7bb6b1a20411241759fe0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/568258
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/compile/internal/ssa/copyelim.go | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/copyelim.go b/src/cmd/compile/internal/ssa/copyelim.go index 17f65127ee..17471e3b5f 100644 --- a/src/cmd/compile/internal/ssa/copyelim.go +++ b/src/cmd/compile/internal/ssa/copyelim.go @@ -11,6 +11,17 @@ func copyelim(f *Func) { // of OpCopy) is a copy. for _, b := range f.Blocks { for _, v := range b.Values { + + // This is an early place in SSA where all values are examined. + // Rewrite all 0-sized Go values to remove accessors, dereferences, loads, etc. + if t := v.Type; (t.IsStruct() || t.IsArray()) && t.Size() == 0 { + if t.IsStruct() { + v.reset(OpStructMake0) + } else { + v.reset(OpArrayMake0) + } + } + copyelimValue(v) } } |