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| author | Michael Munday <mike.munday@ibm.com> | 2020-04-01 03:21:03 -0700 |
|---|---|---|
| committer | Michael Munday <mike.munday@ibm.com> | 2020-04-02 13:38:07 +0000 |
| commit | a7a0f0305035948f4c86e08e6e64409ab11a6f67 (patch) | |
| tree | 3bb5b2e0db73e9cbd7bdd29da9cb9cda413d59eb | |
| parent | 801cd7c84d42dcf18256416524aa0d31d6305830 (diff) | |
| download | go-a7a0f0305035948f4c86e08e6e64409ab11a6f67.tar.gz go-a7a0f0305035948f4c86e08e6e64409ab11a6f67.zip | |
cmd/compile: mark 'store multiple' as clobbering flags on s390x
Store multiple instructions can clobber flags on s390x when the
offset passed into the assembler is outside the range representable
with a signed 20 bit integer. This is because the assembler uses
the agfi instruction to implement the large offset. The assembler
could use a different sequence of instructions, but for now just
mark the instruction as 'clobberFlags' since this is risk free.
Noticed while investigating #38195.
No test yet since I'm not sure how to get this bug to trigger and
I haven't seen it affect real code.
Change-Id: I4a6ab96455a3ef8ffacb76ef0166b97eb40ff925
Reviewed-on: https://go-review.googlesource.com/c/go/+/226759
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
| -rw-r--r-- | src/cmd/compile/internal/ssa/gen/S390XOps.go | 6 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/opGen.go | 6 |
2 files changed, 12 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/gen/S390XOps.go b/src/cmd/compile/internal/ssa/gen/S390XOps.go index 283a0fa6b5..65460bf6f7 100644 --- a/src/cmd/compile/internal/ssa/gen/S390XOps.go +++ b/src/cmd/compile/internal/ssa/gen/S390XOps.go @@ -630,6 +630,7 @@ func init() { asm: "STMG", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, { name: "STMG3", @@ -640,6 +641,7 @@ func init() { asm: "STMG", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, { name: "STMG4", @@ -657,6 +659,7 @@ func init() { asm: "STMG", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, { name: "STM2", @@ -667,6 +670,7 @@ func init() { asm: "STMY", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, { name: "STM3", @@ -677,6 +681,7 @@ func init() { asm: "STMY", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, { name: "STM4", @@ -694,6 +699,7 @@ func init() { asm: "STMY", faultOnNilArg0: true, symEffect: "Write", + clobberFlags: true, // TODO(mundaym): currently uses AGFI to handle large offsets }, // large move diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go index 46ca7936dc..bf48bff8f1 100644 --- a/src/cmd/compile/internal/ssa/opGen.go +++ b/src/cmd/compile/internal/ssa/opGen.go @@ -30110,6 +30110,7 @@ var opcodeTable = [...]opInfo{ name: "STMG2", auxType: auxSymOff, argLen: 4, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMG, @@ -30125,6 +30126,7 @@ var opcodeTable = [...]opInfo{ name: "STMG3", auxType: auxSymOff, argLen: 5, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMG, @@ -30141,6 +30143,7 @@ var opcodeTable = [...]opInfo{ name: "STMG4", auxType: auxSymOff, argLen: 6, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMG, @@ -30158,6 +30161,7 @@ var opcodeTable = [...]opInfo{ name: "STM2", auxType: auxSymOff, argLen: 4, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMY, @@ -30173,6 +30177,7 @@ var opcodeTable = [...]opInfo{ name: "STM3", auxType: auxSymOff, argLen: 5, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMY, @@ -30189,6 +30194,7 @@ var opcodeTable = [...]opInfo{ name: "STM4", auxType: auxSymOff, argLen: 6, + clobberFlags: true, faultOnNilArg0: true, symEffect: SymWrite, asm: s390x.ASTMY, |