[go] cmd/compile: tighten mergelocals address use analysis
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Keith Randall (Gerrit)
Jul 2, 2026, 7:09:56 PMJul 2
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cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops.
TODO: more addrSinkArg marks on arch-dependent ops.
Fixes #80127
Change-Id: Ia722a8314c1ace1b883ecedec1a3e06a2957a6b6
Change diff
diff --git a/src/cmd/compile/internal/liveness/mergelocals.go b/src/cmd/compile/internal/liveness/mergelocals.go
index 6967ee0..28d034a 100644
--- a/src/cmd/compile/internal/liveness/mergelocals.go
+++ b/src/cmd/compile/internal/liveness/mergelocals.go
@@ -513,8 +513,13 @@
}
}
}
- for _, arg := range v.Args {
+ for idx, arg := range v.Args {
if nc, ok := pendingUses[arg.ID]; ok {
+ if !v.AddrSinkArg(idx) {
+ // If this op may propagate the argument address to its output,
+ // then give up. See issue 80127.
+ continue
+ }
// We found a use of some value that took the
// address of nc.n. Record this inst as a
// potential indirect use.
diff --git a/src/cmd/compile/internal/ssa/_gen/AMD64Ops.go b/src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
index 1488201..959aa414 100644
--- a/src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
@@ -998,6 +998,7 @@
inputs: []regMask{gp},
},
faultOnNilArg0: true,
+ addrSinkArg0: true,
},
// arg0 = pointer to start of memory to zero
@@ -1014,6 +1015,7 @@
},
clobberFlags: true,
faultOnNilArg0: true,
+ addrSinkArg0: true,
needIntTemp: true,
},
@@ -1030,6 +1032,7 @@
clobbers: buildReg("DI CX"),
},
faultOnNilArg0: true,
+ addrSinkArg0: true,
},
// With a register ABI, the actual register info for these instructions (i.e., what is used in regalloc) is augmented with per-call-site bindings of additional arguments to specific in and out registers.
@@ -1054,6 +1057,8 @@
},
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
},
// arg0 = destination pointer
// arg1 = source pointer
@@ -1073,6 +1078,8 @@
clobberFlags: true,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
needIntTemp: true,
},
@@ -1090,6 +1097,8 @@
},
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
},
// (InvertFlags (CMPQ a b)) == (CMPQ b a)
diff --git a/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go b/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
index 04d960f..61c2a26 100644
--- a/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
@@ -424,13 +424,13 @@
{name: "FMOVDloadidx", argLength: 3, reg: fp2load, asm: "FMOVD", typ: "Float64"}, // load 64-bit float from arg0 + arg1, arg2=mem.
// shifted register indexed load
- {name: "MOVHloadidx2", argLength: 3, reg: gp2load, asm: "MOVH", typ: "Int16"}, // load 16-bit half-word from arg0 + arg1*2, sign-extended to 64-bit, arg2=mem.
- {name: "MOVHUloadidx2", argLength: 3, reg: gp2load, asm: "MOVHU", typ: "UInt16"}, // load 16-bit half-word from arg0 + arg1*2, zero-extended to 64-bit, arg2=mem.
- {name: "MOVWloadidx4", argLength: 3, reg: gp2load, asm: "MOVW", typ: "Int32"}, // load 32-bit word from arg0 + arg1*4, sign-extended to 64-bit, arg2=mem.
- {name: "MOVWUloadidx4", argLength: 3, reg: gp2load, asm: "MOVWU", typ: "UInt32"}, // load 32-bit word from arg0 + arg1*4, zero-extended to 64-bit, arg2=mem.
- {name: "MOVDloadidx8", argLength: 3, reg: gp2load, asm: "MOVD", typ: "UInt64"}, // load 64-bit double-word from arg0 + arg1*8, arg2 = mem.
- {name: "FMOVSloadidx4", argLength: 3, reg: fp2load, asm: "FMOVS", typ: "Float32"}, // load 32-bit float from arg0 + arg1*4, arg2 = mem.
- {name: "FMOVDloadidx8", argLength: 3, reg: fp2load, asm: "FMOVD", typ: "Float64"}, // load 64-bit float from arg0 + arg1*8, arg2 = mem.
+ {name: "MOVHloadidx2", argLength: 3, reg: gp2load, asm: "MOVH", typ: "Int16"}, // load 16-bit half-word from arg0 + arg1*2, sign-extended to 64-bit, arg2=mem.
+ {name: "MOVHUloadidx2", argLength: 3, reg: gp2load, asm: "MOVHU", typ: "UInt16"}, // load 16-bit half-word from arg0 + arg1*2, zero-extended to 64-bit, arg2=mem.
+ {name: "MOVWloadidx4", argLength: 3, reg: gp2load, asm: "MOVW", typ: "Int32"}, // load 32-bit word from arg0 + arg1*4, sign-extended to 64-bit, arg2=mem.
+ {name: "MOVWUloadidx4", argLength: 3, reg: gp2load, asm: "MOVWU", typ: "UInt32"}, // load 32-bit word from arg0 + arg1*4, zero-extended to 64-bit, arg2=mem.
+ {name: "MOVDloadidx8", argLength: 3, reg: gp2load, asm: "MOVD", typ: "UInt64", addrSinkArg0: true}, // load 64-bit double-word from arg0 + arg1*8, arg2 = mem.
+ {name: "FMOVSloadidx4", argLength: 3, reg: fp2load, asm: "FMOVS", typ: "Float32"}, // load 32-bit float from arg0 + arg1*4, arg2 = mem.
+ {name: "FMOVDloadidx8", argLength: 3, reg: fp2load, asm: "FMOVD", typ: "Float64"}, // load 64-bit float from arg0 + arg1*8, arg2 = mem.
{name: "MOVBstore", argLength: 3, reg: gpstore, aux: "SymOff", asm: "MOVB", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, // store 1 byte of arg1 to arg0 + auxInt + aux. arg2=mem.
{name: "MOVHstore", argLength: 3, reg: gpstore, aux: "SymOff", asm: "MOVH", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, // store 2 bytes of arg1 to arg0 + auxInt + aux. arg2=mem.
@@ -460,11 +460,11 @@
{name: "FMOVDstoreidx", argLength: 4, reg: fpstoreidx, asm: "FMOVD", typ: "Mem"}, // store 64-bit float of arg2 to arg0 + arg1, arg3=mem.
// shifted register indexed store
- {name: "MOVHstoreidx2", argLength: 4, reg: gpstore2, asm: "MOVH", typ: "Mem"}, // store 2 bytes of arg2 to arg0 + arg1*2, arg3 = mem.
- {name: "MOVWstoreidx4", argLength: 4, reg: gpstore2, asm: "MOVW", typ: "Mem"}, // store 4 bytes of arg2 to arg0 + arg1*4, arg3 = mem.
- {name: "MOVDstoreidx8", argLength: 4, reg: gpstore2, asm: "MOVD", typ: "Mem"}, // store 8 bytes of arg2 to arg0 + arg1*8, arg3 = mem.
- {name: "FMOVSstoreidx4", argLength: 4, reg: fpstoreidx, asm: "FMOVS", typ: "Mem"}, // store 32-bit float of arg2 to arg0 + arg1*4, arg3=mem.
- {name: "FMOVDstoreidx8", argLength: 4, reg: fpstoreidx, asm: "FMOVD", typ: "Mem"}, // store 64-bit float of arg2 to arg0 + arg1*8, arg3=mem.
+ {name: "MOVHstoreidx2", argLength: 4, reg: gpstore2, asm: "MOVH", typ: "Mem"}, // store 2 bytes of arg2 to arg0 + arg1*2, arg3 = mem.
+ {name: "MOVWstoreidx4", argLength: 4, reg: gpstore2, asm: "MOVW", typ: "Mem"}, // store 4 bytes of arg2 to arg0 + arg1*4, arg3 = mem.
+ {name: "MOVDstoreidx8", argLength: 4, reg: gpstore2, asm: "MOVD", typ: "Mem", addrSinkArg0: true}, // store 8 bytes of arg2 to arg0 + arg1*8, arg3 = mem.
+ {name: "FMOVSstoreidx4", argLength: 4, reg: fpstoreidx, asm: "FMOVS", typ: "Mem"}, // store 32-bit float of arg2 to arg0 + arg1*4, arg3=mem.
+ {name: "FMOVDstoreidx8", argLength: 4, reg: fpstoreidx, asm: "FMOVD", typ: "Mem"}, // store 64-bit float of arg2 to arg0 + arg1*8, arg3=mem.
{name: "FMOVDgpfp", argLength: 1, reg: gpfp, asm: "FMOVD", earlyOk: true}, // move int64 to float64 (no conversion)
{name: "FMOVDfpgp", argLength: 1, reg: fpgp, asm: "FMOVD", earlyOk: true}, // move float64 to int64 (no conversion)
@@ -584,6 +584,7 @@
inputs: []regMask{gp},
},
faultOnNilArg0: true,
+ addrSinkArg0: true,
},
// large zeroing
@@ -600,6 +601,7 @@
clobbersArg0: true,
},
faultOnNilArg0: true,
+ addrSinkArg0: true,
needIntTemp: true,
},
@@ -619,6 +621,8 @@
},
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
},
// large copying
@@ -639,6 +643,8 @@
},
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
},
// Scheduler ensures LoweredGetClosurePtr occurs only in entry block,
diff --git a/src/cmd/compile/internal/ssa/_gen/main.go b/src/cmd/compile/internal/ssa/_gen/main.go
index 1e8de5f..c2c1a04 100644
--- a/src/cmd/compile/internal/ssa/_gen/main.go
+++ b/src/cmd/compile/internal/ssa/_gen/main.go
@@ -73,6 +73,8 @@
unsafePoint bool // this op is an unsafe point, i.e. not safe for async preemption
fixedReg bool // this op will be assigned a fixed register
earlyOk bool // executing this op in an earlier block is ok
+ addrSinkArg0 bool // the address in arg0 does not propagate to the result
+ addrSinkArg1 bool // the address in arg1 does not propagate to the result
symEffect string // effect this op has on symbol in aux
scale uint8 // amd64/386 indexed load scale
}
@@ -397,6 +399,12 @@
if v.earlyOk {
fmt.Fprintln(w, "earlyOk: true,")
}
+ if v.addrSinkArg0 {
+ fmt.Fprintln(w, "addrSinkArg0: true,")
+ }
+ if v.addrSinkArg1 {
+ fmt.Fprintln(w, "addrSinkArg1: true,")
+ }
if v.unsafePoint {
fmt.Fprintln(w, "unsafePoint: true,")
}
diff --git a/src/cmd/compile/internal/ssa/op.go b/src/cmd/compile/internal/ssa/op.go
index 2d2676b..85fdb08 100644
--- a/src/cmd/compile/internal/ssa/op.go
+++ b/src/cmd/compile/internal/ssa/op.go
@@ -47,6 +47,8 @@
unsafePoint bool // this op is an unsafe point, i.e. not safe for async preemption
fixedReg bool // this op will be assigned a fixed register
earlyOk bool // executing this op in an earlier block is ok
+ addrSinkArg0 bool // the address in arg0 does not propagate to the result
+ addrSinkArg1 bool // the address in arg1 does not propagate to the result
symEffect SymEffect // effect this op has on symbol in aux
scale uint8 // amd64/386 indexed load scale
}
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index f79a83c..fe72118 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -19564,6 +19564,7 @@
auxType: auxInt64,
argLen: 2,
faultOnNilArg0: true,
+ addrSinkArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 49135, v2: 0}}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
@@ -19577,6 +19578,7 @@
clobberFlags: true,
needIntTemp: true,
faultOnNilArg0: true,
+ addrSinkArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 49135, v2: 0}}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
@@ -19588,6 +19590,7 @@
name: "REPSTOSQ",
argLen: 4,
faultOnNilArg0: true,
+ addrSinkArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 128, v2: 0}}, // DI
@@ -19665,6 +19668,8 @@
argLen: 3,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 49135, v2: 0}}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
@@ -19681,6 +19686,8 @@
needIntTemp: true,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 49135, v2: 0}}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
@@ -19696,6 +19703,8 @@
argLen: 4,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 128, v2: 0}}, // DI
@@ -77690,9 +77699,10 @@
},
},
{
- name: "MOVDloadidx8",
- argLen: 3,
- asm: arm64.AMOVD,
+ name: "MOVDloadidx8",
+ argLen: 3,
+ addrSinkArg0: true,
+ asm: arm64.AMOVD,
reg: regInfo{
inputs: []inputInfo{
{1, regMask{v1: 402653183, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -78001,9 +78011,10 @@
},
},
{
- name: "MOVDstoreidx8",
- argLen: 4,
- asm: arm64.AMOVD,
+ name: "MOVDstoreidx8",
+ argLen: 4,
+ addrSinkArg0: true,
+ asm: arm64.AMOVD,
reg: regInfo{
inputs: []inputInfo{
{1, regMask{v1: 939524095, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30 ZERO
@@ -79076,6 +79087,7 @@
auxType: auxInt64,
argLen: 2,
faultOnNilArg0: true,
+ addrSinkArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 335544319, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 R30
@@ -79088,6 +79100,7 @@
argLen: 2,
needIntTemp: true,
faultOnNilArg0: true,
+ addrSinkArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 335544319, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 R30
@@ -79101,6 +79114,8 @@
argLen: 3,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 318767103, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R26 R30
@@ -79115,6 +79130,8 @@
argLen: 3,
faultOnNilArg0: true,
faultOnNilArg1: true,
+ addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 310378495, v2: 0}}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R26 R30
diff --git a/src/cmd/compile/internal/ssa/value.go b/src/cmd/compile/internal/ssa/value.go
index 95710d9..279099d 100644
--- a/src/cmd/compile/internal/ssa/value.go
+++ b/src/cmd/compile/internal/ssa/value.go
@@ -665,3 +665,15 @@
return true
}
}
+
+// AddrSinkArg reports whether the idx'th argument is known
+// to not propagate to the output value.
+func (v *Value) AddrSinkArg(idx int) bool {
+ if idx == 0 {
+ return opcodeTable[v.Op].addrSinkArg0
+ }
+ if idx == 1 {
+ return opcodeTable[v.Op].addrSinkArg1
+ }
+ return false
+}
diff --git a/test/fixedbugs/issue80127.go b/test/fixedbugs/issue80127.go
new file mode 100644
index 0000000..b76c3d4
--- /dev/null
+++ b/test/fixedbugs/issue80127.go
@@ -0,0 +1,30 @@
+// run
+
+// Copyright 2026 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+type T [2][2]int64
+
+//go:noinline
+func f(i, j int) int64 {
+ if i < 0 || i > 1 || j < 0 || j > 1 {
+ return 3
+ }
+ var x T
+ x[i][i] = 33
+
+ var y T
+ y[i][i] = 44
+ r := y[j][j]
+
+ return r + x[i][i]
+}
+
+func main() {
+ if x := f(1, 1); x != 77 {
+ println("bad", x)
+ }
+}
Change information
Files:
- M src/cmd/compile/internal/liveness/mergelocals.go
- M src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
- M src/cmd/compile/internal/ssa/_gen/main.go
- M src/cmd/compile/internal/ssa/op.go
- M src/cmd/compile/internal/ssa/opGen.go
- M src/cmd/compile/internal/ssa/value.go
- A test/fixedbugs/issue80127.go
Change size: M
Delta: 8 files changed, 108 insertions(+), 19 deletions(-)
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Keith Randall . resolved
Ping, like to get this in for 1.27.
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Junyang Shao . resolved
It looks like this has no performance penalty but stack frame might be bigger for some binaries, which sounds fine 😊
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Change information
Commit message:
cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops. The only typical use
of an explicit address is initial zeroing (which this CL handles).
Fixes #80127
Change-Id: Ia722a8314c1ace1b883ecedec1a3e06a2957a6b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/796001
Reviewed-by: Junyang Shao <shaoj...@google.com>
Reviewed-by: Keith Randall <k...@google.com>
LUCI-TryBot-Result: golang...@luci-project-accounts.iam.gserviceaccount.com <golang...@luci-project-accounts.iam.gserviceaccount.com>
Files:
- M src/cmd/compile/internal/liveness/mergelocals.go
- M src/cmd/compile/internal/ssa/_gen/386Ops.go
- M src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARMOps.go
- M src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPS64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPSOps.go
- M src/cmd/compile/internal/ssa/_gen/PPC64Ops.go
- M src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
- M src/cmd/compile/internal/ssa/_gen/S390XOps.go
- M src/cmd/compile/internal/ssa/_gen/WasmOps.go
- M src/cmd/compile/internal/ssa/_gen/main.go
- M src/cmd/compile/internal/ssa/op.go
- M src/cmd/compile/internal/ssa/opGen.go
- M src/cmd/compile/internal/ssa/value.go
- A test/fixedbugs/issue80127.go
Change size: XL
Delta: 17 files changed, 2582 insertions(+), 1673 deletions(-)
Branch: refs/heads/master
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Keith Randall (Gerrit)
Jul 20, 2026, 3:48:55 PM (2 days ago) Jul 20
to goph...@pubsubhelper.golang.org, Keith Randall, golang-co...@googlegroups.com
Keith Randall has uploaded the change for review![]( "Open in Gerrit")
Commit message
[release-branch.go1.27] cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops. The only typical use
of an explicit address is initial zeroing (which this CL handles).
Fixes #80127
Change-Id: Ia722a8314c1ace1b883ecedec1a3e06a2957a6b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/796001
Reviewed-by: Junyang Shao <shaoj...@google.com>
Reviewed-by: Keith Randall <k...@google.com>
LUCI-TryBot-Result: golang...@luci-project-accounts.iam.gserviceaccount.com <golang...@luci-project-accounts.iam.gserviceaccount.com>
(cherry picked from commit 06bc6592c3336596ec8904357efb333203d05170)
Change diff
Change information
Files:
- M src/cmd/compile/internal/liveness/mergelocals.go
- M src/cmd/compile/internal/ssa/_gen/386Ops.go
- M src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARMOps.go
- M src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPS64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPSOps.go
- M src/cmd/compile/internal/ssa/_gen/PPC64Ops.go
- M src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
- M src/cmd/compile/internal/ssa/_gen/S390XOps.go
- M src/cmd/compile/internal/ssa/_gen/WasmOps.go
- M src/cmd/compile/internal/ssa/_gen/main.go
- M src/cmd/compile/internal/ssa/op.go
- M src/cmd/compile/internal/ssa/opGen.go
- M src/cmd/compile/internal/ssa/value.go
- A test/fixedbugs/issue80127.go
Change size: XL
Delta: 17 files changed, 2582 insertions(+), 1673 deletions(-)
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Commit message
[release-branch.go1.26] cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops. The only typical use
of an explicit address is initial zeroing (which this CL handles).
Fixes #80478
Change-Id: Ia722a8314c1ace1b883ecedec1a3e06a2957a6b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/796001
Reviewed-by: Junyang Shao <shaoj...@google.com>
Reviewed-by: Keith Randall <k...@google.com>
Change diff
Change information
Files:
- M src/cmd/compile/internal/liveness/mergelocals.go
- M src/cmd/compile/internal/ssa/_gen/386Ops.go
- M src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARMOps.go
- M src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPS64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPSOps.go
- M src/cmd/compile/internal/ssa/_gen/PPC64Ops.go
- M src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
- M src/cmd/compile/internal/ssa/_gen/S390XOps.go
- M src/cmd/compile/internal/ssa/_gen/WasmOps.go
- M src/cmd/compile/internal/ssa/_gen/main.go
- M src/cmd/compile/internal/ssa/op.go
- M src/cmd/compile/internal/ssa/opGen.go
- M src/cmd/compile/internal/ssa/value.go
- A test/fixedbugs/issue80127.go
Change size: XL
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Commit message
[release-branch.go1.25] cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops. The only typical use
of an explicit address is initial zeroing (which this CL handles).
Fixes #80477
Change diff
Delta: 17 files changed, 2553 insertions(+), 1668 deletions(-)
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Patchset-level comments
File-level comment, Patchset 5 (Latest):
Cherry Mui . unresolved
This CL breaks 32-bit ARM builders
https://ci.chromium.org/ui/p/golang/builders/ci/gotip-linux-arm/b8675725464899937841/overview
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1 is the latest approved patch-set.
The change was submitted with unreviewed changes in the following files:
```
The name of the file: src/cmd/compile/internal/ssa/opGen.go
Insertions: 2, Deletions: 0.
@@ -75061,6 +75061,7 @@
clobberFlags: true,
faultOnNilArg0: true,
addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 2, v2: 0}}, // R1
@@ -100989,6 +100990,7 @@
clobberFlags: true,
faultOnNilArg0: true,
addrSinkArg0: true,
+ addrSinkArg1: true,
reg: regInfo{
inputs: []inputInfo{
{0, regMask{v1: 2, v2: 0}}, // R1
```
```
The name of the file: src/cmd/compile/internal/liveness/mergelocals.go
Insertions: 16, Deletions: 3.
@@ -516,9 +516,22 @@
for idx, arg := range v.Args {
if nc, ok := pendingUses[arg.ID]; ok {
if !v.AddrSinkArg(idx) {
- // If this op may propagate the argument address to its output,
- // then give up. See issue 80127.
- continue
+ // If this op may propagate its input address
+ // to somewhere else, we must track where that
+ // somewhere else might be. See issue 80127.
+ if v.Type.IsMemory() {
+ // Might be stored to memory. Give up.
+ continue
+ }
+ // Some sort of address arithmetic.
+ if _, ok := pendingUses[v.ID]; ok {
+ // v has used multiple addresses, which is something
+ // we can't keep track of. Give up.
+ continue
+ }
+ // Treat this op as producing the address of the same variable
+ // that its argument was the address of.
+ pendingUses[v.ID] = nameCount{n: nc.n, count: v.Uses}
}
// We found a use of some value that took the
// address of nc.n. Record this inst as a
```
```
The name of the file: src/cmd/compile/internal/ssa/_gen/ARMOps.go
Insertions: 2, Deletions: 0.
@@ -508,6 +508,7 @@
clobberFlags: true,
faultOnNilArg0: true,
addrSinkArg0: true,
+ addrSinkArg1: true,
},
// large or unaligned move
@@ -533,6 +534,7 @@
faultOnNilArg1: true,
addrSinkArg0: true,
addrSinkArg1: true,
+ // TODO: could use addrSinkArg2 here.
},
// Scheduler ensures LoweredGetClosurePtr occurs only in entry block,
```
```
The name of the file: src/cmd/compile/internal/ssa/_gen/S390XOps.go
Insertions: 2, Deletions: 0.
@@ -758,6 +758,7 @@
faultOnNilArg1: true,
addrSinkArg0: true,
addrSinkArg1: true,
+ // TODO: could use addrSinkArg2 here.
},
// large clear
@@ -784,6 +785,7 @@
typ: "Mem",
faultOnNilArg0: true,
addrSinkArg0: true,
+ addrSinkArg1: true,
},
}
```
Change information
Commit message:
[release-branch.go1.27] cmd/compile: tighten mergelocals address use analysis
We currently look for all uses of the address of a local, to find the
maximum extent of the lifetime of a local. But the analysis doesn't
handle the case where a use of the address is itself just a copy or
pointer arithmetic, and the result of that use is then subsequently
used outside the lifetime we currently compute.
Maybe we could track down uses of uses, etc. But we do the safer thing
here which is just to consider only uses that we know aren't propagating
the address anywhere. Any other uses are considered bad and abort
merging for the affected local. This is conservative but easy to reason
about. In practice, these address copies don't come up all that often,
as they are usually folded into load/store ops. The only typical use
of an explicit address is initial zeroing (which this CL handles).
Fixes #80127
Change-Id: Ia722a8314c1ace1b883ecedec1a3e06a2957a6b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/796001
Reviewed-by: Junyang Shao <shaoj...@google.com>
Reviewed-by: Keith Randall <k...@google.com>
LUCI-TryBot-Result: golang...@luci-project-accounts.iam.gserviceaccount.com <golang...@luci-project-accounts.iam.gserviceaccount.com>
(cherry picked from commit 06bc6592c3336596ec8904357efb333203d05170)
Reviewed-on: https://go-review.googlesource.com/c/go/+/803240
Files:
- M src/cmd/compile/internal/liveness/mergelocals.go
- M src/cmd/compile/internal/ssa/_gen/386Ops.go
- M src/cmd/compile/internal/ssa/_gen/AMD64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
- M src/cmd/compile/internal/ssa/_gen/ARMOps.go
- M src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPS64Ops.go
- M src/cmd/compile/internal/ssa/_gen/MIPSOps.go
- M src/cmd/compile/internal/ssa/_gen/PPC64Ops.go
- M src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
- M src/cmd/compile/internal/ssa/_gen/S390XOps.go
- M src/cmd/compile/internal/ssa/_gen/WasmOps.go
- M src/cmd/compile/internal/ssa/_gen/main.go
- M src/cmd/compile/internal/ssa/op.go
- M src/cmd/compile/internal/ssa/opGen.go
- M src/cmd/compile/internal/ssa/value.go
- A test/fixedbugs/issue80127.go
Change size: XL
Delta: 17 files changed, 2601 insertions(+), 1673 deletions(-)
Branch: refs/heads/release-branch.go1.27
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