diff --git a/src/xenia/cpu/backend/x64/x64_emitter.cc b/src/xenia/cpu/backend/x64/x64_emitter.cc
index 92f45d493..4076c0d65 100644
--- a/src/xenia/cpu/backend/x64/x64_emitter.cc
+++ b/src/xenia/cpu/backend/x64/x64_emitter.cc
@@ -801,7 +801,7 @@ void X64Emitter::LoadConstantXmm(Xbyak::Xmm dest, const vec128_t& v) {
   if (!v.low && !v.high) {
     // 0000...
     vpxor(dest, dest);
-  } else if (v.low == ~0ull && v.high == ~0ull) {
+  } else if (v.low == ~uint64_t(0) && v.high == ~uint64_t(0)) {
     // 1111...
     vpcmpeqb(dest, dest);
   } else {
@@ -818,10 +818,10 @@ void X64Emitter::LoadConstantXmm(Xbyak::Xmm dest, float v) {
     float f;
     uint32_t i;
   } x = {v};
-  if (!v) {
-    // 0
+  if (!x.i) {
+    // +0.0f (but not -0.0f because it may be used to flip the sign via xor).
     vpxor(dest, dest);
-  } else if (x.i == ~0U) {
+  } else if (x.i == ~uint32_t(0)) {
     // 1111...
     vpcmpeqb(dest, dest);
   } else {
@@ -837,10 +837,10 @@ void X64Emitter::LoadConstantXmm(Xbyak::Xmm dest, double v) {
     double d;
     uint64_t i;
   } x = {v};
-  if (!v) {
-    // 0
+  if (!x.i) {
+    // +0.0 (but not -0.0 because it may be used to flip the sign via xor).
     vpxor(dest, dest);
-  } else if (x.i == ~0ULL) {
+  } else if (x.i == ~uint64_t(0)) {
     // 1111...
     vpcmpeqb(dest, dest);
   } else {