Index: lib/CodeGen/GlobalISel/IRTranslator.cpp
===================================================================
--- lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -285,8 +285,6 @@
 
 bool IRTranslator::translateBinaryOp(unsigned Opcode, const User &U,
                                      MachineIRBuilder &MIRBuilder) {
-  // FIXME: handle signed/unsigned wrapping flags.
-
   // Get or create a virtual register for each value.
   // Unless the value is a Constant => loadimm cst?
   // or inline constant each time?
@@ -308,18 +306,29 @@
   // -0.0 - X --> G_FNEG
   if (isa<Constant>(U.getOperand(0)) &&
       U.getOperand(0) == ConstantFP::getZeroValueForNegation(U.getType())) {
-    MIRBuilder.buildInstr(TargetOpcode::G_FNEG)
-        .addDef(getOrCreateVReg(U))
-        .addUse(getOrCreateVReg(*U.getOperand(1)));
+    unsigned Op1 = getOrCreateVReg(*U.getOperand(1));
+    unsigned Res = getOrCreateVReg(U);
+    uint16_t Flags = 0;
+    if (isa<Instruction>(U)) {
+      const Instruction &I = cast<Instruction>(U);
+      Flags = MachineInstr::copyFlagsFromInstruction(I);
+    }
+    // Negate the last operand of the FSUB
+    MIRBuilder.buildInstr(TargetOpcode::G_FNEG, {Res}, {Op1}, Flags);
     return true;
   }
   return translateBinaryOp(TargetOpcode::G_FSUB, U, MIRBuilder);
 }
 
 bool IRTranslator::translateFNeg(const User &U, MachineIRBuilder &MIRBuilder) {
-  MIRBuilder.buildInstr(TargetOpcode::G_FNEG)
-      .addDef(getOrCreateVReg(U))
-      .addUse(getOrCreateVReg(*U.getOperand(0)));
+  unsigned Op0 = getOrCreateVReg(*U.getOperand(0));
+  unsigned Res = getOrCreateVReg(U);
+  uint16_t Flags = 0;
+  if (isa<Instruction>(U)) {
+    const Instruction &I = cast<Instruction>(U);
+    Flags = MachineInstr::copyFlagsFromInstruction(I);
+  }
+  MIRBuilder.buildInstr(TargetOpcode::G_FNEG, {Res}, {Op0}, Flags);
   return true;
 }
 
Index: test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
===================================================================
--- test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -1530,18 +1530,18 @@
 define float @test_fneg_f32(float %x) {
 ; CHECK-LABEL: name: test_fneg_f32
 ; CHECK: [[ARG:%[0-9]+]]:_(s32) = COPY $s0
-; CHECK: [[RES:%[0-9]+]]:_(s32) = G_FNEG [[ARG]]
+; CHECK: [[RES:%[0-9]+]]:_(s32) = nnan ninf nsz arcp contract afn reassoc G_FNEG [[ARG]]
 ; CHECK: $s0 = COPY [[RES]](s32)
-  %neg = fsub float -0.000000e+00, %x
+  %neg = fsub fast float -0.000000e+00, %x
   ret float %neg
 }
 
 define double @test_fneg_f64(double %x) {
 ; CHECK-LABEL: name: test_fneg_f64
 ; CHECK: [[ARG:%[0-9]+]]:_(s64) = COPY $d0
-; CHECK: [[RES:%[0-9]+]]:_(s64) = G_FNEG [[ARG]]
+; CHECK: [[RES:%[0-9]+]]:_(s64) = nnan ninf nsz arcp contract afn reassoc G_FNEG [[ARG]]
 ; CHECK: $d0 = COPY [[RES]](s64)
-  %neg = fsub double -0.000000e+00, %x
+  %neg = fsub fast double -0.000000e+00, %x
   ret double %neg
 }