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cmd/compile: ensure S390X moves don't overflow int32

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Break ADDconst into ADD + MOVDconst, so that if the constant
is too big it won't overflow ADDconst's constant field.

For normal sizes, other rules will recombine into an ADDconst.

Fixes S390X breakage from CL 33909.

Change-Id: Id804ee052365527efb580f797688b0ce83c47915
Reviewed-on: https://go-review.googlesource.com/c/151597
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Michael Munday <mike.munday@ibm.com>
This commit is contained in:
Keith Randall 2018-11-28 12:41:23 -08:00 committed by Keith Randall
parent 96d41786c5
commit 4f15b54780
2 changed files with 6 additions and 4 deletions
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2
src/cmd/compile/internal/ssa/gen/S390X.rules
View File

@ -350,7 +350,7 @@
// Move more than 1024 bytes using a loop.
(Move [s] dst src mem) && s > 1024 ->
(LoweredMove [s%256] dst src (ADDconst <src.Type> src [(s/256)*256]) mem)
(LoweredMove [s%256] dst src (ADD <src.Type> src (MOVDconst [(s/256)*256])) mem)
// Lowering Zero instructions
(Zero [0] _ mem) -> mem

8
src/cmd/compile/internal/ssa/rewriteS390X.go
View File

@ -4799,7 +4799,7 @@ func rewriteValueS390X_OpMove_10(v *Value) bool {
}
// match: (Move [s] dst src mem)
// cond: s > 1024
// result: (LoweredMove [s%256] dst src (ADDconst <src.Type> src [(s/256)*256]) mem)
// result: (LoweredMove [s%256] dst src (ADD <src.Type> src (MOVDconst [(s/256)*256])) mem)
for {
s := v.AuxInt
_ = v.Args[2]
@ -4813,9 +4813,11 @@ func rewriteValueS390X_OpMove_10(v *Value) bool {
v.AuxInt = s % 256
v.AddArg(dst)
v.AddArg(src)
v0 := b.NewValue0(v.Pos, OpS390XADDconst, src.Type)
v0.AuxInt = (s / 256) * 256
v0 := b.NewValue0(v.Pos, OpS390XADD, src.Type)
v0.AddArg(src)
v1 := b.NewValue0(v.Pos, OpS390XMOVDconst, typ.UInt64)
v1.AuxInt = (s / 256) * 256
v0.AddArg(v1)
v.AddArg(v0)
v.AddArg(mem)
return true