diff --git a/CMakeLists.txt b/CMakeLists.txt
index fbd8673ce4..fe8660559c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -221,7 +221,6 @@ set(ZIG_STAGE2_SOURCES
     lib/compiler_rt/aulldiv.zig
     lib/compiler_rt/aullrem.zig
     lib/compiler_rt/bswap.zig
-    lib/compiler_rt/ceil.zig
     lib/compiler_rt/clear_cache.zig
     lib/compiler_rt/cmp.zig
     lib/compiler_rt/cmpdf2.zig
@@ -312,7 +311,7 @@ set(ZIG_STAGE2_SOURCES
     lib/compiler_rt/floatuntisf.zig
     lib/compiler_rt/floatuntitf.zig
     lib/compiler_rt/floatuntixf.zig
-    lib/compiler_rt/floor.zig
+    lib/compiler_rt/floor_ceil.zig
     lib/compiler_rt/fma.zig
     lib/compiler_rt/fmax.zig
     lib/compiler_rt/fmin.zig
diff --git a/lib/compiler_rt.zig b/lib/compiler_rt.zig
index 5a21cf7b34..87ff89c2d9 100644
--- a/lib/compiler_rt.zig
+++ b/lib/compiler_rt.zig
@@ -231,12 +231,11 @@ comptime {
     _ = @import("compiler_rt/divtc3.zig");
 
     // Math routines. Alphabetically sorted.
-    _ = @import("compiler_rt/ceil.zig");
     _ = @import("compiler_rt/cos.zig");
     _ = @import("compiler_rt/exp.zig");
     _ = @import("compiler_rt/exp2.zig");
     _ = @import("compiler_rt/fabs.zig");
-    _ = @import("compiler_rt/floor.zig");
+    _ = @import("compiler_rt/floor_ceil.zig");
     _ = @import("compiler_rt/fma.zig");
     _ = @import("compiler_rt/fmax.zig");
     _ = @import("compiler_rt/fmin.zig");
diff --git a/lib/compiler_rt/ceil.zig b/lib/compiler_rt/ceil.zig
deleted file mode 100644
index 9f797346f6..0000000000
--- a/lib/compiler_rt/ceil.zig
+++ /dev/null
@@ -1,236 +0,0 @@
-//! Ported from musl, which is MIT licensed.
-//! https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
-//!
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceilf.c
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceil.c
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceill.c
-
-const std = @import("std");
-const builtin = @import("builtin");
-const arch = builtin.cpu.arch;
-const math = std.math;
-const mem = std.mem;
-const expect = std.testing.expect;
-const common = @import("common.zig");
-
-comptime {
-    @export(&__ceilh, .{ .name = "__ceilh", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&ceilf, .{ .name = "ceilf", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&ceil, .{ .name = "ceil", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&__ceilx, .{ .name = "__ceilx", .linkage = common.linkage, .visibility = common.visibility });
-    if (common.want_ppc_abi) {
-        @export(&ceilq, .{ .name = "ceilf128", .linkage = common.linkage, .visibility = common.visibility });
-    }
-    @export(&ceilq, .{ .name = "ceilq", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&ceill, .{ .name = "ceill", .linkage = common.linkage, .visibility = common.visibility });
-}
-
-pub fn __ceilh(x: f16) callconv(.c) f16 {
-    var u: u16 = @bitCast(x);
-    const e = @as(i16, @intCast((u >> 10) & 31)) - 15;
-    var m: u16 = undefined;
-
-    if (e >= 10) return x;
-
-    if (e >= 0) {
-        m = @as(u16, 0x03FF) >> @intCast(e);
-        if (u & m == 0) return x;
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        if (u >> 15 == 0) u += m;
-        u &= ~m;
-        return @bitCast(u);
-    } else {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        return if (u >> 15 != 0) -0.0 else if (u << 1 != 0) 1.0 else x;
-    }
-}
-
-pub fn ceilf(x: f32) callconv(.c) f32 {
-    var u: u32 = @bitCast(x);
-    const e = @as(i32, @intCast((u >> 23) & 0xFF)) - 0x7F;
-    var m: u32 = undefined;
-
-    if (e >= 23) return x;
-
-    if (e >= 0) {
-        m = @as(u32, 0x007FFFFF) >> @intCast(e);
-        if (u & m == 0) return x;
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        if (u >> 31 == 0) u += m;
-        u &= ~m;
-        return @bitCast(u);
-    } else {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        return if (u >> 31 != 0) -0.0 else if (u << 1 != 0) 1.0 else x;
-    }
-}
-
-pub fn ceil(x: f64) callconv(.c) f64 {
-    const f64_toint = 1.0 / math.floatEps(f64);
-
-    const u: u64 = @bitCast(x);
-    const e = (u >> 52) & 0x7FF;
-    var y: f64 = undefined;
-
-    if (e >= 0x3FF + 52 or x == 0) {
-        return x;
-    }
-
-    if (u >> 63 != 0) {
-        y = x - f64_toint + f64_toint - x;
-    } else {
-        y = x + f64_toint - f64_toint - x;
-    }
-
-    if (e <= 0x3FF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 63 != 0) {
-            return -0.0;
-        } else {
-            return 1.0;
-        }
-    } else if (y < 0) {
-        return x + y + 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn __ceilx(x: f80) callconv(.c) f80 {
-    const f80_toint = 1.0 / math.floatEps(f80);
-
-    const u: u80 = @bitCast(x);
-    const e = (u >> 64) & 0x7FFF;
-    var y: f80 = undefined;
-
-    if (e >= 0x3FFF + 64 or x == 0) return x;
-
-    if (u >> 79 != 0) {
-        y = x - f80_toint + f80_toint - x;
-    } else {
-        y = x + f80_toint - f80_toint - x;
-    }
-
-    if (e <= 0x3FFF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 79 != 0) {
-            return -0.0;
-        } else {
-            return 1.0;
-        }
-    } else if (y < 0) {
-        return x + y + 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn ceilq(x: f128) callconv(.c) f128 {
-    const f128_toint = 1.0 / math.floatEps(f128);
-
-    const u: u128 = @bitCast(x);
-    const e = (u >> 112) & 0x7FFF;
-    var y: f128 = undefined;
-
-    if (e >= 0x3FFF + 112 or x == 0) return x;
-
-    if (u >> 127 != 0) {
-        y = x - f128_toint + f128_toint - x;
-    } else {
-        y = x + f128_toint - f128_toint - x;
-    }
-
-    if (e <= 0x3FFF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 127 != 0) {
-            return -0.0;
-        } else {
-            return 1.0;
-        }
-    } else if (y < 0) {
-        return x + y + 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn ceill(x: c_longdouble) callconv(.c) c_longdouble {
-    switch (@typeInfo(c_longdouble).float.bits) {
-        16 => return __ceilh(x),
-        32 => return ceilf(x),
-        64 => return ceil(x),
-        80 => return __ceilx(x),
-        128 => return ceilq(x),
-        else => @compileError("unreachable"),
-    }
-}
-
-test "ceil16" {
-    try expect(__ceilh(1.3) == 2.0);
-    try expect(__ceilh(-1.3) == -1.0);
-    try expect(__ceilh(0.2) == 1.0);
-}
-
-test "ceil32" {
-    try expect(ceilf(1.3) == 2.0);
-    try expect(ceilf(-1.3) == -1.0);
-    try expect(ceilf(0.2) == 1.0);
-}
-
-test "ceil64" {
-    try expect(ceil(1.3) == 2.0);
-    try expect(ceil(-1.3) == -1.0);
-    try expect(ceil(0.2) == 1.0);
-}
-
-test "ceil80" {
-    try expect(__ceilx(1.3) == 2.0);
-    try expect(__ceilx(-1.3) == -1.0);
-    try expect(__ceilx(0.2) == 1.0);
-}
-
-test "ceil128" {
-    try expect(ceilq(1.3) == 2.0);
-    try expect(ceilq(-1.3) == -1.0);
-    try expect(ceilq(0.2) == 1.0);
-}
-
-test "ceil16.special" {
-    try expect(__ceilh(0.0) == 0.0);
-    try expect(__ceilh(-0.0) == -0.0);
-    try expect(math.isPositiveInf(__ceilh(math.inf(f16))));
-    try expect(math.isNegativeInf(__ceilh(-math.inf(f16))));
-    try expect(math.isNan(__ceilh(math.nan(f16))));
-}
-
-test "ceil32.special" {
-    try expect(ceilf(0.0) == 0.0);
-    try expect(ceilf(-0.0) == -0.0);
-    try expect(math.isPositiveInf(ceilf(math.inf(f32))));
-    try expect(math.isNegativeInf(ceilf(-math.inf(f32))));
-    try expect(math.isNan(ceilf(math.nan(f32))));
-}
-
-test "ceil64.special" {
-    try expect(ceil(0.0) == 0.0);
-    try expect(ceil(-0.0) == -0.0);
-    try expect(math.isPositiveInf(ceil(math.inf(f64))));
-    try expect(math.isNegativeInf(ceil(-math.inf(f64))));
-    try expect(math.isNan(ceil(math.nan(f64))));
-}
-
-test "ceil80.special" {
-    try expect(__ceilx(0.0) == 0.0);
-    try expect(__ceilx(-0.0) == -0.0);
-    try expect(math.isPositiveInf(__ceilx(math.inf(f80))));
-    try expect(math.isNegativeInf(__ceilx(-math.inf(f80))));
-    try expect(math.isNan(__ceilx(math.nan(f80))));
-}
-
-test "ceil128.special" {
-    try expect(ceilq(0.0) == 0.0);
-    try expect(ceilq(-0.0) == -0.0);
-    try expect(math.isPositiveInf(ceilq(math.inf(f128))));
-    try expect(math.isNegativeInf(ceilq(-math.inf(f128))));
-    try expect(math.isNan(ceilq(math.nan(f128))));
-}
diff --git a/lib/compiler_rt/floor.zig b/lib/compiler_rt/floor.zig
deleted file mode 100644
index 7510abed66..0000000000
--- a/lib/compiler_rt/floor.zig
+++ /dev/null
@@ -1,236 +0,0 @@
-//! Ported from musl, which is licensed under the MIT license:
-//! https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
-//!
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/floorf.c
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/floor.c
-//! https://git.musl-libc.org/cgit/musl/tree/src/math/floorl.c
-
-const std = @import("std");
-const builtin = @import("builtin");
-const math = std.math;
-const mem = std.mem;
-const expect = std.testing.expect;
-const arch = builtin.cpu.arch;
-const common = @import("common.zig");
-
-comptime {
-    @export(&__floorh, .{ .name = "__floorh", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&floorf, .{ .name = "floorf", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&floor, .{ .name = "floor", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&__floorx, .{ .name = "__floorx", .linkage = common.linkage, .visibility = common.visibility });
-    if (common.want_ppc_abi) {
-        @export(&floorq, .{ .name = "floorf128", .linkage = common.linkage, .visibility = common.visibility });
-    }
-    @export(&floorq, .{ .name = "floorq", .linkage = common.linkage, .visibility = common.visibility });
-    @export(&floorl, .{ .name = "floorl", .linkage = common.linkage, .visibility = common.visibility });
-}
-
-pub fn __floorh(x: f16) callconv(.c) f16 {
-    var u: u16 = @bitCast(x);
-    const e = @as(i16, @intCast((u >> 10) & 31)) - 15;
-    var m: u16 = undefined;
-
-    if (e >= 10) return x;
-
-    if (e >= 0) {
-        m = @as(u16, 0x03FF) >> @intCast(e);
-        if (u & m == 0) return x;
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        if (u >> 15 != 0) u += m;
-        return @bitCast(u & ~m);
-    } else {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        return if (u >> 15 == 0) 0.0 else if (u << 1 != 0) -1.0 else x;
-    }
-}
-
-pub fn floorf(x: f32) callconv(.c) f32 {
-    var u: u32 = @bitCast(x);
-    const e = @as(i32, @intCast((u >> 23) & 0xFF)) - 0x7F;
-    var m: u32 = undefined;
-
-    if (e >= 23) return x;
-
-    if (e >= 0) {
-        m = @as(u32, 0x007FFFFF) >> @intCast(e);
-        if (u & m == 0) return x;
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        if (u >> 31 != 0) u += m;
-        return @bitCast(u & ~m);
-    } else {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
-        return if (u >> 31 == 0) 0.0 else if (u << 1 != 0) -1.0 else x;
-    }
-}
-
-pub fn floor(x: f64) callconv(.c) f64 {
-    const f64_toint = 1.0 / math.floatEps(f64);
-
-    const u: u64 = @bitCast(x);
-    const e = (u >> 52) & 0x7FF;
-    var y: f64 = undefined;
-
-    if (e >= 0x3FF + 52 or x == 0) {
-        return x;
-    }
-
-    if (u >> 63 != 0) {
-        y = x - f64_toint + f64_toint - x;
-    } else {
-        y = x + f64_toint - f64_toint - x;
-    }
-
-    if (e <= 0x3FF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 63 != 0) {
-            return -1.0;
-        } else {
-            return 0.0;
-        }
-    } else if (y > 0) {
-        return x + y - 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn __floorx(x: f80) callconv(.c) f80 {
-    const f80_toint = 1.0 / math.floatEps(f80);
-
-    const u: u80 = @bitCast(x);
-    const e = (u >> 64) & 0x7FFF;
-    var y: f80 = undefined;
-
-    if (e >= 0x3FFF + 64 or x == 0) {
-        return x;
-    }
-
-    if (u >> 79 != 0) {
-        y = x - f80_toint + f80_toint - x;
-    } else {
-        y = x + f80_toint - f80_toint - x;
-    }
-
-    if (e <= 0x3FFF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 79 != 0) {
-            return -1.0;
-        } else {
-            return 0.0;
-        }
-    } else if (y > 0) {
-        return x + y - 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn floorq(x: f128) callconv(.c) f128 {
-    const f128_toint = 1.0 / math.floatEps(f128);
-
-    const u: u128 = @bitCast(x);
-    const e = (u >> 112) & 0x7FFF;
-    var y: f128 = undefined;
-
-    if (e >= 0x3FFF + 112 or x == 0) return x;
-
-    if (u >> 127 != 0) {
-        y = x - f128_toint + f128_toint - x;
-    } else {
-        y = x + f128_toint - f128_toint - x;
-    }
-
-    if (e <= 0x3FFF - 1) {
-        if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
-        if (u >> 127 != 0) {
-            return -1.0;
-        } else {
-            return 0.0;
-        }
-    } else if (y > 0) {
-        return x + y - 1;
-    } else {
-        return x + y;
-    }
-}
-
-pub fn floorl(x: c_longdouble) callconv(.c) c_longdouble {
-    switch (@typeInfo(c_longdouble).float.bits) {
-        16 => return __floorh(x),
-        32 => return floorf(x),
-        64 => return floor(x),
-        80 => return __floorx(x),
-        128 => return floorq(x),
-        else => @compileError("unreachable"),
-    }
-}
-
-test "floor16" {
-    try expect(__floorh(1.3) == 1.0);
-    try expect(__floorh(-1.3) == -2.0);
-    try expect(__floorh(0.2) == 0.0);
-}
-
-test "floor32" {
-    try expect(floorf(1.3) == 1.0);
-    try expect(floorf(-1.3) == -2.0);
-    try expect(floorf(0.2) == 0.0);
-}
-
-test "floor64" {
-    try expect(floor(1.3) == 1.0);
-    try expect(floor(-1.3) == -2.0);
-    try expect(floor(0.2) == 0.0);
-}
-
-test "floor80" {
-    try expect(__floorx(1.3) == 1.0);
-    try expect(__floorx(-1.3) == -2.0);
-    try expect(__floorx(0.2) == 0.0);
-}
-
-test "floor128" {
-    try expect(floorq(1.3) == 1.0);
-    try expect(floorq(-1.3) == -2.0);
-    try expect(floorq(0.2) == 0.0);
-}
-
-test "floor16.special" {
-    try expect(__floorh(0.0) == 0.0);
-    try expect(__floorh(-0.0) == -0.0);
-    try expect(math.isPositiveInf(__floorh(math.inf(f16))));
-    try expect(math.isNegativeInf(__floorh(-math.inf(f16))));
-    try expect(math.isNan(__floorh(math.nan(f16))));
-}
-
-test "floor32.special" {
-    try expect(floorf(0.0) == 0.0);
-    try expect(floorf(-0.0) == -0.0);
-    try expect(math.isPositiveInf(floorf(math.inf(f32))));
-    try expect(math.isNegativeInf(floorf(-math.inf(f32))));
-    try expect(math.isNan(floorf(math.nan(f32))));
-}
-
-test "floor64.special" {
-    try expect(floor(0.0) == 0.0);
-    try expect(floor(-0.0) == -0.0);
-    try expect(math.isPositiveInf(floor(math.inf(f64))));
-    try expect(math.isNegativeInf(floor(-math.inf(f64))));
-    try expect(math.isNan(floor(math.nan(f64))));
-}
-
-test "floor80.special" {
-    try expect(__floorx(0.0) == 0.0);
-    try expect(__floorx(-0.0) == -0.0);
-    try expect(math.isPositiveInf(__floorx(math.inf(f80))));
-    try expect(math.isNegativeInf(__floorx(-math.inf(f80))));
-    try expect(math.isNan(__floorx(math.nan(f80))));
-}
-
-test "floor128.special" {
-    try expect(floorq(0.0) == 0.0);
-    try expect(floorq(-0.0) == -0.0);
-    try expect(math.isPositiveInf(floorq(math.inf(f128))));
-    try expect(math.isNegativeInf(floorq(-math.inf(f128))));
-    try expect(math.isNan(floorq(math.nan(f128))));
-}
diff --git a/lib/compiler_rt/floor_ceil.zig b/lib/compiler_rt/floor_ceil.zig
new file mode 100644
index 0000000000..e669cb812d
--- /dev/null
+++ b/lib/compiler_rt/floor_ceil.zig
@@ -0,0 +1,284 @@
+//! Ported from musl, which is MIT licensed.
+//! https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+//!
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceilf.c
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceil.c
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/ceill.c
+//!
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/floorf.c
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/floor.c
+//! https://git.musl-libc.org/cgit/musl/tree/src/math/floorl.c
+
+const std = @import("std");
+const math = std.math;
+const mem = std.mem;
+const expect = std.testing.expect;
+
+const common = @import("common.zig");
+
+comptime {
+    // floor
+    @export(&__floorh, .{ .name = "__floorh", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&floorf, .{ .name = "floorf", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&floor, .{ .name = "floor", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&__floorx, .{ .name = "__floorx", .linkage = common.linkage, .visibility = common.visibility });
+    if (common.want_ppc_abi) {
+        @export(&floorq, .{ .name = "floorf128", .linkage = common.linkage, .visibility = common.visibility });
+    }
+    @export(&floorq, .{ .name = "floorq", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&floorl, .{ .name = "floorl", .linkage = common.linkage, .visibility = common.visibility });
+
+    // ceil
+    @export(&__ceilh, .{ .name = "__ceilh", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&ceilf, .{ .name = "ceilf", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&ceil, .{ .name = "ceil", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&__ceilx, .{ .name = "__ceilx", .linkage = common.linkage, .visibility = common.visibility });
+    if (common.want_ppc_abi) {
+        @export(&ceilq, .{ .name = "ceilf128", .linkage = common.linkage, .visibility = common.visibility });
+    }
+    @export(&ceilq, .{ .name = "ceilq", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&ceill, .{ .name = "ceill", .linkage = common.linkage, .visibility = common.visibility });
+}
+
+pub fn __floorh(x: f16) callconv(.c) f16 {
+    return impl(f16, .floor, x);
+}
+
+pub fn floorf(x: f32) callconv(.c) f32 {
+    return impl(f32, .floor, x);
+}
+
+pub fn floor(x: f64) callconv(.c) f64 {
+    return impl(f64, .floor, x);
+}
+
+pub fn __floorx(x: f80) callconv(.c) f80 {
+    return impl(f80, .floor, x);
+}
+
+pub fn floorq(x: f128) callconv(.c) f128 {
+    return impl(f128, .floor, x);
+}
+
+pub fn floorl(x: c_longdouble) callconv(.c) c_longdouble {
+    return impl(std.meta.Float(@bitSizeOf(c_longdouble)), .floor, x);
+}
+
+pub fn __ceilh(x: f16) callconv(.c) f16 {
+    return impl(f16, .ceil, x);
+}
+
+pub fn ceilf(x: f32) callconv(.c) f32 {
+    return impl(f32, .ceil, x);
+}
+
+pub fn ceil(x: f64) callconv(.c) f64 {
+    return impl(f64, .ceil, x);
+}
+
+pub fn __ceilx(x: f80) callconv(.c) f80 {
+    return impl(f80, .ceil, x);
+}
+
+pub fn ceilq(x: f128) callconv(.c) f128 {
+    return impl(f128, .ceil, x);
+}
+
+pub fn ceill(x: c_longdouble) callconv(.c) c_longdouble {
+    return impl(std.meta.Float(@bitSizeOf(c_longdouble)), .ceil, x);
+}
+
+inline fn impl(comptime T: type, comptime op: enum { floor, ceil }, x: T) T {
+    const C = 1.0 / math.floatEps(T);
+    const mantissa = math.floatMantissaBits(T);
+    const mask = (1 << math.floatExponentBits(T)) - 1;
+    const bias = (1 << (math.floatExponentBits(T) - 1)) - 1;
+
+    const bits = @bitSizeOf(T);
+    const U = @Int(.unsigned, bits);
+    var u: U = @bitCast(x);
+    switch (T) {
+        f16, f32 => {
+            const e = @as(@Int(.signed, bits), @intCast((u >> mantissa) & mask)) - bias;
+            if (e >= mantissa) return x;
+
+            if (e >= 0) {
+                const m = (@as(U, 1) << @intCast(mantissa - e)) - 1;
+                if (u & m == 0) return x;
+                if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
+                if (u >> bits - 1 == @intFromBool(op == .floor)) u += m;
+                return @bitCast(u & ~m);
+            } else {
+                if (common.want_float_exceptions) mem.doNotOptimizeAway(x + 0x1.0p120);
+                return switch (op) {
+                    .floor => if (u >> bits - 1 == 0) 0.0 else if (u << 1 != 0) -1.0 else x,
+                    .ceil => if (u >> bits - 1 != 0) -0.0 else if (u << 1 != 0) 1.0 else x,
+                };
+            }
+        },
+        f64, f80, f128 => {
+            const e = (u >> mantissa) & mask;
+            if (e >= bias + math.floatFractionalBits(T) or x == 0) return x;
+
+            const positive = u >> @bitSizeOf(T) - 1 == 0;
+            const y: T = if (positive)
+                x + C - C - x
+            else
+                x - C + C - x;
+
+            if (e <= bias - 1) {
+                if (common.want_float_exceptions) mem.doNotOptimizeAway(y);
+                return switch (op) {
+                    .floor => if (positive) 0.0 else -1.0,
+                    .ceil => if (positive) 1.0 else -0.0,
+                };
+            }
+            switch (op) {
+                .floor => if (y > 0) return x + y - 1,
+                .ceil => if (y < 0) return x + y + 1,
+            }
+            return x + y;
+        },
+        else => unreachable,
+    }
+}
+
+test "floor16" {
+    try expect(__floorh(1.3) == 1.0);
+    try expect(__floorh(-1.3) == -2.0);
+    try expect(__floorh(0.2) == 0.0);
+}
+
+test "floor32" {
+    try expect(floorf(1.3) == 1.0);
+    try expect(floorf(-1.3) == -2.0);
+    try expect(floorf(0.2) == 0.0);
+}
+
+test "floor64" {
+    try expect(floor(1.3) == 1.0);
+    try expect(floor(-1.3) == -2.0);
+    try expect(floor(0.2) == 0.0);
+}
+
+test "floor80" {
+    try expect(__floorx(1.3) == 1.0);
+    try expect(__floorx(-1.3) == -2.0);
+    try expect(__floorx(0.2) == 0.0);
+}
+
+test "floor128" {
+    try expect(floorq(1.3) == 1.0);
+    try expect(floorq(-1.3) == -2.0);
+    try expect(floorq(0.2) == 0.0);
+}
+
+test "floor16.special" {
+    try expect(__floorh(0.0) == 0.0);
+    try expect(__floorh(-0.0) == -0.0);
+    try expect(math.isPositiveInf(__floorh(math.inf(f16))));
+    try expect(math.isNegativeInf(__floorh(-math.inf(f16))));
+    try expect(math.isNan(__floorh(math.nan(f16))));
+}
+
+test "floor32.special" {
+    try expect(floorf(0.0) == 0.0);
+    try expect(floorf(-0.0) == -0.0);
+    try expect(math.isPositiveInf(floorf(math.inf(f32))));
+    try expect(math.isNegativeInf(floorf(-math.inf(f32))));
+    try expect(math.isNan(floorf(math.nan(f32))));
+}
+
+test "floor64.special" {
+    try expect(floor(0.0) == 0.0);
+    try expect(floor(-0.0) == -0.0);
+    try expect(math.isPositiveInf(floor(math.inf(f64))));
+    try expect(math.isNegativeInf(floor(-math.inf(f64))));
+    try expect(math.isNan(floor(math.nan(f64))));
+}
+
+test "floor80.special" {
+    try expect(__floorx(0.0) == 0.0);
+    try expect(__floorx(-0.0) == -0.0);
+    try expect(math.isPositiveInf(__floorx(math.inf(f80))));
+    try expect(math.isNegativeInf(__floorx(-math.inf(f80))));
+    try expect(math.isNan(__floorx(math.nan(f80))));
+}
+
+test "floor128.special" {
+    try expect(floorq(0.0) == 0.0);
+    try expect(floorq(-0.0) == -0.0);
+    try expect(math.isPositiveInf(floorq(math.inf(f128))));
+    try expect(math.isNegativeInf(floorq(-math.inf(f128))));
+    try expect(math.isNan(floorq(math.nan(f128))));
+}
+
+test "ceil16" {
+    try expect(__ceilh(1.3) == 2.0);
+    try expect(__ceilh(-1.3) == -1.0);
+    try expect(__ceilh(0.2) == 1.0);
+}
+
+test "ceil32" {
+    try expect(ceilf(1.3) == 2.0);
+    try expect(ceilf(-1.3) == -1.0);
+    try expect(ceilf(0.2) == 1.0);
+}
+
+test "ceil64" {
+    try expect(ceil(1.3) == 2.0);
+    try expect(ceil(-1.3) == -1.0);
+    try expect(ceil(0.2) == 1.0);
+}
+
+test "ceil80" {
+    try expect(__ceilx(1.3) == 2.0);
+    try expect(__ceilx(-1.3) == -1.0);
+    try expect(__ceilx(0.2) == 1.0);
+}
+
+test "ceil128" {
+    try expect(ceilq(1.3) == 2.0);
+    try expect(ceilq(-1.3) == -1.0);
+    try expect(ceilq(0.2) == 1.0);
+}
+
+test "ceil16.special" {
+    try expect(__ceilh(0.0) == 0.0);
+    try expect(__ceilh(-0.0) == -0.0);
+    try expect(math.isPositiveInf(__ceilh(math.inf(f16))));
+    try expect(math.isNegativeInf(__ceilh(-math.inf(f16))));
+    try expect(math.isNan(__ceilh(math.nan(f16))));
+}
+
+test "ceil32.special" {
+    try expect(ceilf(0.0) == 0.0);
+    try expect(ceilf(-0.0) == -0.0);
+    try expect(math.isPositiveInf(ceilf(math.inf(f32))));
+    try expect(math.isNegativeInf(ceilf(-math.inf(f32))));
+    try expect(math.isNan(ceilf(math.nan(f32))));
+}
+
+test "ceil64.special" {
+    try expect(ceil(0.0) == 0.0);
+    try expect(ceil(-0.0) == -0.0);
+    try expect(math.isPositiveInf(ceil(math.inf(f64))));
+    try expect(math.isNegativeInf(ceil(-math.inf(f64))));
+    try expect(math.isNan(ceil(math.nan(f64))));
+}
+
+test "ceil80.special" {
+    try expect(__ceilx(0.0) == 0.0);
+    try expect(__ceilx(-0.0) == -0.0);
+    try expect(math.isPositiveInf(__ceilx(math.inf(f80))));
+    try expect(math.isNegativeInf(__ceilx(-math.inf(f80))));
+    try expect(math.isNan(__ceilx(math.nan(f80))));
+}
+
+test "ceil128.special" {
+    try expect(ceilq(0.0) == 0.0);
+    try expect(ceilq(-0.0) == -0.0);
+    try expect(math.isPositiveInf(ceilq(math.inf(f128))));
+    try expect(math.isNegativeInf(ceilq(-math.inf(f128))));
+    try expect(math.isNan(ceilq(math.nan(f128))));
+}
diff --git a/test/behavior/floatop.zig b/test/behavior/floatop.zig
index 78d858774f..7e140f8da1 100644
--- a/test/behavior/floatop.zig
+++ b/test/behavior/floatop.zig
@@ -1298,6 +1298,24 @@ test "@ceil f80/f128/c_longdouble" {
     try comptime testCeil(c_longdouble);
 }
 
+test "@ceil f80 maxInt(u64)" {
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_c and builtin.cpu.arch.isArm()) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
+
+    if (builtin.zig_backend == .stage2_llvm and builtin.os.tag == .windows) {
+        // https://github.com/ziglang/zig/issues/12602
+        return error.SkipZigTest;
+    }
+
+    var x: u64 = std.math.maxInt(u64);
+    x = x;
+    const float: f80 = @floatFromInt(x);
+    try std.testing.expect(float == @ceil(float));
+}
+
 fn testCeil(comptime T: type) !void {
     var two_point_one: T = 2.1;
     try expect(@ceil(two_point_one) == 3.0);