cmd/compile: mark s390x int <-> float conversions as clobbering flags

These conversion instructions set the condition code and so should be marked as clobbering flags. Fixes #39651. Change-Id: I91cc9687ea70ef0551bb3139c1875071c349d43e Reviewed-on: https://go-review.googlesource.com/c/go/+/238628 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
golang · Jun 18, 2020 · 377c153 · 377c153
1 parent 4379fa1
commit 377c153
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diff --git a/src/cmd/compile/internal/ssa/gen/S390XOps.go b/src/cmd/compile/internal/ssa/gen/S390XOps.go
@@ -394,24 +394,25 @@ func init() {
 
 		{name: "MOVDconst", reg: gp01, asm: "MOVD", typ: "UInt64", aux: "Int64", rematerializeable: true}, // auxint
 
-		{name: "LDGR", argLength: 1, reg: gpfp, asm: "LDGR"},     // move int64 to float64 (no conversion)
-		{name: "LGDR", argLength: 1, reg: fpgp, asm: "LGDR"},     // move float64 to int64 (no conversion)
-		{name: "CFDBRA", argLength: 1, reg: fpgp, asm: "CFDBRA"}, // convert float64 to int32
-		{name: "CGDBRA", argLength: 1, reg: fpgp, asm: "CGDBRA"}, // convert float64 to int64
-		{name: "CFEBRA", argLength: 1, reg: fpgp, asm: "CFEBRA"}, // convert float32 to int32
-		{name: "CGEBRA", argLength: 1, reg: fpgp, asm: "CGEBRA"}, // convert float32 to int64
-		{name: "CEFBRA", argLength: 1, reg: gpfp, asm: "CEFBRA"}, // convert int32 to float32
-		{name: "CDFBRA", argLength: 1, reg: gpfp, asm: "CDFBRA"}, // convert int32 to float64
-		{name: "CEGBRA", argLength: 1, reg: gpfp, asm: "CEGBRA"}, // convert int64 to float32
-		{name: "CDGBRA", argLength: 1, reg: gpfp, asm: "CDGBRA"}, // convert int64 to float64
-		{name: "CLFEBR", argLength: 1, reg: fpgp, asm: "CLFEBR"}, // convert float32 to uint32
-		{name: "CLFDBR", argLength: 1, reg: fpgp, asm: "CLFDBR"}, // convert float64 to uint32
-		{name: "CLGEBR", argLength: 1, reg: fpgp, asm: "CLGEBR"}, // convert float32 to uint64
-		{name: "CLGDBR", argLength: 1, reg: fpgp, asm: "CLGDBR"}, // convert float64 to uint64
-		{name: "CELFBR", argLength: 1, reg: gpfp, asm: "CELFBR"}, // convert uint32 to float32
-		{name: "CDLFBR", argLength: 1, reg: gpfp, asm: "CDLFBR"}, // convert uint32 to float64
-		{name: "CELGBR", argLength: 1, reg: gpfp, asm: "CELGBR"}, // convert uint64 to float32
-		{name: "CDLGBR", argLength: 1, reg: gpfp, asm: "CDLGBR"}, // convert uint64 to float64
+		{name: "LDGR", argLength: 1, reg: gpfp, asm: "LDGR"}, // move int64 to float64 (no conversion)
+		{name: "LGDR", argLength: 1, reg: fpgp, asm: "LGDR"}, // move float64 to int64 (no conversion)
+
+		{name: "CFDBRA", argLength: 1, reg: fpgp, asm: "CFDBRA", clobberFlags: true}, // convert float64 to int32
+		{name: "CGDBRA", argLength: 1, reg: fpgp, asm: "CGDBRA", clobberFlags: true}, // convert float64 to int64
+		{name: "CFEBRA", argLength: 1, reg: fpgp, asm: "CFEBRA", clobberFlags: true}, // convert float32 to int32
+		{name: "CGEBRA", argLength: 1, reg: fpgp, asm: "CGEBRA", clobberFlags: true}, // convert float32 to int64
+		{name: "CEFBRA", argLength: 1, reg: gpfp, asm: "CEFBRA", clobberFlags: true}, // convert int32 to float32
+		{name: "CDFBRA", argLength: 1, reg: gpfp, asm: "CDFBRA", clobberFlags: true}, // convert int32 to float64
+		{name: "CEGBRA", argLength: 1, reg: gpfp, asm: "CEGBRA", clobberFlags: true}, // convert int64 to float32
+		{name: "CDGBRA", argLength: 1, reg: gpfp, asm: "CDGBRA", clobberFlags: true}, // convert int64 to float64
+		{name: "CLFEBR", argLength: 1, reg: fpgp, asm: "CLFEBR", clobberFlags: true}, // convert float32 to uint32
+		{name: "CLFDBR", argLength: 1, reg: fpgp, asm: "CLFDBR", clobberFlags: true}, // convert float64 to uint32
+		{name: "CLGEBR", argLength: 1, reg: fpgp, asm: "CLGEBR", clobberFlags: true}, // convert float32 to uint64
+		{name: "CLGDBR", argLength: 1, reg: fpgp, asm: "CLGDBR", clobberFlags: true}, // convert float64 to uint64
+		{name: "CELFBR", argLength: 1, reg: gpfp, asm: "CELFBR", clobberFlags: true}, // convert uint32 to float32
+		{name: "CDLFBR", argLength: 1, reg: gpfp, asm: "CDLFBR", clobberFlags: true}, // convert uint32 to float64
+		{name: "CELGBR", argLength: 1, reg: gpfp, asm: "CELGBR", clobberFlags: true}, // convert uint64 to float32
+		{name: "CDLGBR", argLength: 1, reg: gpfp, asm: "CDLGBR", clobberFlags: true}, // convert uint64 to float64
 
 		{name: "LEDBR", argLength: 1, reg: fp11, asm: "LEDBR"}, // convert float64 to float32
 		{name: "LDEBR", argLength: 1, reg: fp11, asm: "LDEBR"}, // convert float32 to float64

diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
diff --git a/test/fixedbugs/issue39651.go b/test/fixedbugs/issue39651.go
@@ -0,0 +1,26 @@
+// run
+
+// Copyright 2020 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.
+
+// Test that float -> integer conversion doesn't clobber
+// flags.
+
+package main
+
+//go:noinline
+func f(x, y float64, a, b *bool, r *int64) {
+	*a = x < y    // set flags
+	*r = int64(x) // clobber flags
+	*b = x == y   // use flags
+}
+
+func main() {
+	var a, b bool
+	var r int64
+	f(1, 1, &a, &b, &r)
+	if a || !b {
+		panic("comparison incorrect")
+	}
+}