[dev.boringcrypto.go1.9] all: merge go1.9.7 into dev.boringcrypto.go1.9dev.boringcrypto.go1.9

Change-Id: I1f9769a0c2c7c090886afa31c86c403da29d2013

1 files changed, 13 insertions, 1 deletions

diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index ab2e38208d..7909072340 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -1272,6 +1272,13 @@ opswitch:
 		}
 		if cs != nil {
 			cmp := Op(n.Etype)
+			// Our comparison below assumes that the non-constant string
+			// is on the left hand side, so rewrite "" cmp x to x cmp "".
+			// See issue 24817.
+			if Isconst(n.Left, CTSTR) {
+				cmp = brrev(cmp)
+			}
+
 			// maxRewriteLen was chosen empirically.
 			// It is the value that minimizes cmd/go file size
 			// across most architectures.
@@ -3390,18 +3397,23 @@ func walkcompare(n *Node, init *Nodes) *Node {
 				i++
 				remains -= t.Elem().Width
 			} else {
+				elemType := t.Elem().ToUnsigned()
 				cmplw := nod(OINDEX, cmpl, nodintconst(int64(i)))
-				cmplw = conv(cmplw, convType)
+				cmplw = conv(cmplw, elemType) // convert to unsigned
+				cmplw = conv(cmplw, convType) // widen
 				cmprw := nod(OINDEX, cmpr, nodintconst(int64(i)))
+				cmprw = conv(cmprw, elemType)
 				cmprw = conv(cmprw, convType)
 				// For code like this:  uint32(s[0]) | uint32(s[1])<<8 | uint32(s[2])<<16 ...
 				// ssa will generate a single large load.
 				for offset := int64(1); offset < step; offset++ {
 					lb := nod(OINDEX, cmpl, nodintconst(int64(i+offset)))
+					lb = conv(lb, elemType)
 					lb = conv(lb, convType)
 					lb = nod(OLSH, lb, nodintconst(int64(8*t.Elem().Width*offset)))
 					cmplw = nod(OOR, cmplw, lb)
 					rb := nod(OINDEX, cmpr, nodintconst(int64(i+offset)))
+					rb = conv(rb, elemType)
 					rb = conv(rb, convType)
 					rb = nod(OLSH, rb, nodintconst(int64(8*t.Elem().Width*offset)))
 					cmprw = nod(OOR, cmprw, rb)