Value: fix comparison of NaN in compareHeteroAdvanaced

Sema: fix equality comparison of signed zeroes and NaN in compareScalar
tests: add test coverage for vector float comparisons

src/Sema.zig

@@ -38137,6 +38137,11 @@ fn compareScalar(
     const pt = sema.pt;
     const coerced_lhs = try pt.getCoerced(lhs, ty);
     const coerced_rhs = try pt.getCoerced(rhs, ty);
+
+    // Equality comparisons of signed zero and NaN need to use floating point semantics
+    if (coerced_lhs.isFloat(pt.zcu) or coerced_rhs.isFloat(pt.zcu))
+        return Value.compareHeteroSema(coerced_lhs, op, coerced_rhs, pt);
+
     switch (op) {
         .eq => return sema.valuesEqual(coerced_lhs, coerced_rhs, ty),
         .neq => return !(try sema.valuesEqual(coerced_lhs, coerced_rhs, ty)),

src/Value.zig

@@ -1132,6 +1132,8 @@ pub fn compareHeteroAdvanced(
             else => {},
         }
     }
+
+    if (lhs.isNan(zcu) or rhs.isNan(zcu)) return op == .neq;
     return (try orderAdvanced(lhs, rhs, strat, zcu, tid)).compare(op);
 }
 

test/behavior/floatop.zig

@@ -194,7 +194,7 @@ fn testCmp(comptime T: type) !void {
         try expect(x <= 2.0);
     }
 
-    @setEvalBranchQuota(2_000);
+    @setEvalBranchQuota(4_000);
     var edges = [_]T{
         -math.inf(T),
         -math.floatMax(T),
@@ -210,6 +210,7 @@ fn testCmp(comptime T: type) !void {
     };
     _ = &edges;
     for (edges, 0..) |rhs, rhs_i| {
+        const rhs_v: @Vector(4, T) = @splat(rhs);
         for (edges, 0..) |lhs, lhs_i| {
             const no_nan = lhs_i != 5 and rhs_i != 5;
             const lhs_order = if (lhs_i < 5) lhs_i else lhs_i - 2;
@@ -220,6 +221,14 @@ fn testCmp(comptime T: type) !void {
             try expect((lhs > rhs) == (no_nan and lhs_order > rhs_order));
             try expect((lhs <= rhs) == (no_nan and lhs_order <= rhs_order));
             try expect((lhs >= rhs) == (no_nan and lhs_order >= rhs_order));
+
+            const lhs_v: @Vector(4, T) = @splat(lhs);
+            try expect(@reduce(.And, (lhs_v == rhs_v)) == (no_nan and lhs_order == rhs_order));
+            try expect(@reduce(.And, (lhs_v != rhs_v)) == !(no_nan and lhs_order == rhs_order));
+            try expect(@reduce(.And, (lhs_v < rhs_v)) == (no_nan and lhs_order < rhs_order));
+            try expect(@reduce(.And, (lhs_v > rhs_v)) == (no_nan and lhs_order > rhs_order));
+            try expect(@reduce(.And, (lhs_v <= rhs_v)) == (no_nan and lhs_order <= rhs_order));
+            try expect(@reduce(.And, (lhs_v >= rhs_v)) == (no_nan and lhs_order >= rhs_order));
         }
     }
 }