From: Keith Randall <keithr@alum.mit.edu>
Date: Wed, 28 Nov 2018 20:41:23 +0000 (-0800)
Subject: cmd/compile: ensure S390X moves don't overflow int32
X-Git-Tag: go1.12beta1~240
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=4f15b54780af7159732794f9d67c9a8a455bbf61;p=gostls13.git

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

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>
---

diff --git a/src/cmd/compile/internal/ssa/gen/S390X.rules b/src/cmd/compile/internal/ssa/gen/S390X.rules
index de2c09c2d1..0aeea53561 100644
--- a/src/cmd/compile/internal/ssa/gen/S390X.rules
+++ b/src/cmd/compile/internal/ssa/gen/S390X.rules
@@ -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
diff --git a/src/cmd/compile/internal/ssa/rewriteS390X.go b/src/cmd/compile/internal/ssa/rewriteS390X.go
index dce7a52529..1695b08780 100644
--- a/src/cmd/compile/internal/ssa/rewriteS390X.go
+++ b/src/cmd/compile/internal/ssa/rewriteS390X.go
@@ -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