PPC/s390: Implement VisitFloat32Neg/VisitFloat64Neg and instr lcebr for s390

src/s390/assembler-s390.cc

Index: src/s390/assembler-s390.cc
diff --git a/src/s390/assembler-s390.cc b/src/s390/assembler-s390.cc
index 673ef61b0de94dffb6579dc9c30c6ae8855581ed..251cbd201f729b77d90038bbb00b5b4ce1a33077 100644
--- a/src/s390/assembler-s390.cc
+++ b/src/s390/assembler-s390.cc
@@ -2748,6 +2748,12 @@ void Assembler::lcdbr(DoubleRegister r1, DoubleRegister r2) {
            Register::from_code(r2.code()));
 }
 
+// Load Complement Register-Register (LB)
+void Assembler::lcebr(DoubleRegister r1, DoubleRegister r2) {
+  rre_form(LCEBR, Register::from_code(r1.code()),
+           Register::from_code(r2.code()));
+}
+
 // Load Positive Register-Register (LB)
 void Assembler::lpebr(DoubleRegister r1, DoubleRegister r2) {
   rre_form(LPEBR, Register::from_code(r1.code()),