diff --git a/lib/compiler_rt/common.zig b/lib/compiler_rt/common.zig
index a75b7d1d0005..1f95d31c037c 100644
--- a/lib/compiler_rt/common.zig
+++ b/lib/compiler_rt/common.zig
@@ -17,6 +17,10 @@ pub const want_aeabi = switch (builtin.abi) {
 };
 pub const want_ppc_abi = builtin.cpu.arch.isPPC() or builtin.cpu.arch.isPPC64();
 
+// Libcalls that involve u128 on Windows x86-64 are expected by LLVM to use the
+// calling convention of @Vector(2, u64), rather than what's standard.
+pub const want_windows_v2u64_abi = builtin.os.tag == .windows and builtin.cpu.arch == .x86_64;
+
 /// This governs whether to use these symbol names for f16/f32 conversions
 /// rather than the standard names:
 /// * __gnu_f2h_ieee
diff --git a/lib/compiler_rt/fixdfti.zig b/lib/compiler_rt/fixdfti.zig
index b2476ce2f3f1..532b27107208 100644
--- a/lib/compiler_rt/fixdfti.zig
+++ b/lib/compiler_rt/fixdfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixdfti, .{ .name = "__fixdfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixdfti_windows_x86_64, .{ .name = "__fixdfti", .linkage = common.linkage });
+    } else {
+        @export(__fixdfti, .{ .name = "__fixdfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixdfti(a: f64) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixdfti_windows_x86_64(a: f64) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(i128, a));
+}
diff --git a/lib/compiler_rt/fixhfti.zig b/lib/compiler_rt/fixhfti.zig
index 36fc1bf60758..b6774968ddc3 100644
--- a/lib/compiler_rt/fixhfti.zig
+++ b/lib/compiler_rt/fixhfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixhfti, .{ .name = "__fixhfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixhfti_windows_x86_64, .{ .name = "__fixhfti", .linkage = common.linkage });
+    } else {
+        @export(__fixhfti, .{ .name = "__fixhfti", .linkage = common.linkage });
+    }
 }
 
-fn __fixhfti(a: f16) callconv(.C) i128 {
+pub fn __fixhfti(a: f16) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixhfti_windows_x86_64(a: f16) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(i128, a));
+}
diff --git a/lib/compiler_rt/fixsfti.zig b/lib/compiler_rt/fixsfti.zig
index 4bf68ec8b0c9..5aa4068b6265 100644
--- a/lib/compiler_rt/fixsfti.zig
+++ b/lib/compiler_rt/fixsfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixsfti, .{ .name = "__fixsfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixsfti_windows_x86_64, .{ .name = "__fixsfti", .linkage = common.linkage });
+    } else {
+        @export(__fixsfti, .{ .name = "__fixsfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixsfti(a: f32) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixsfti_windows_x86_64(a: f32) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(i128, a));
+}
diff --git a/lib/compiler_rt/fixtfti.zig b/lib/compiler_rt/fixtfti.zig
index 9ba761729e58..ba46eb85980a 100644
--- a/lib/compiler_rt/fixtfti.zig
+++ b/lib/compiler_rt/fixtfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixtfti, .{ .name = "__fixtfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixtfti_windows_x86_64, .{ .name = "__fixtfti", .linkage = common.linkage });
+    } else {
+        @export(__fixtfti, .{ .name = "__fixtfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixtfti(a: f128) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixtfti_windows_x86_64(a: f128) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(i128, a));
+}
diff --git a/lib/compiler_rt/fixunsdfti.zig b/lib/compiler_rt/fixunsdfti.zig
index ce3c4aabddd2..00a89ba2d6f0 100644
--- a/lib/compiler_rt/fixunsdfti.zig
+++ b/lib/compiler_rt/fixunsdfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunsdfti, .{ .name = "__fixunsdfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixunsdfti_windows_x86_64, .{ .name = "__fixunsdfti", .linkage = common.linkage });
+    } else {
+        @export(__fixunsdfti, .{ .name = "__fixunsdfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixunsdfti(a: f64) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixunsdfti_windows_x86_64(a: f64) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(u128, a));
+}
diff --git a/lib/compiler_rt/fixunshfti.zig b/lib/compiler_rt/fixunshfti.zig
index b804c52f9613..4f5179bfb5bf 100644
--- a/lib/compiler_rt/fixunshfti.zig
+++ b/lib/compiler_rt/fixunshfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunshfti, .{ .name = "__fixunshfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixunshfti_windows_x86_64, .{ .name = "__fixunshfti", .linkage = common.linkage });
+    } else {
+        @export(__fixunshfti, .{ .name = "__fixunshfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixunshfti(a: f16) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v2u64 = @import("std").meta.Vector(2, u64);
+
+fn __fixunshfti_windows_x86_64(a: f16) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(u128, a));
+}
diff --git a/lib/compiler_rt/fixunssfti.zig b/lib/compiler_rt/fixunssfti.zig
index 7b1965b5abf6..0d3fa5d3b965 100644
--- a/lib/compiler_rt/fixunssfti.zig
+++ b/lib/compiler_rt/fixunssfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunssfti, .{ .name = "__fixunssfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixunssfti_windows_x86_64, .{ .name = "__fixunssfti", .linkage = common.linkage });
+    } else {
+        @export(__fixunssfti, .{ .name = "__fixunssfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixunssfti(a: f32) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixunssfti_windows_x86_64(a: f32) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(u128, a));
+}
diff --git a/lib/compiler_rt/fixunstfti.zig b/lib/compiler_rt/fixunstfti.zig
index 5e39db106527..02cabd4d46bb 100644
--- a/lib/compiler_rt/fixunstfti.zig
+++ b/lib/compiler_rt/fixunstfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunstfti, .{ .name = "__fixunstfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixunstfti_windows_x86_64, .{ .name = "__fixunstfti", .linkage = common.linkage });
+    } else {
+        @export(__fixunstfti, .{ .name = "__fixunstfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixunstfti(a: f128) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixunstfti_windows_x86_64(a: f128) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(u128, a));
+}
diff --git a/lib/compiler_rt/fixunsxfti.zig b/lib/compiler_rt/fixunsxfti.zig
index acd41469be13..1cf5891f92ce 100644
--- a/lib/compiler_rt/fixunsxfti.zig
+++ b/lib/compiler_rt/fixunsxfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunsxfti, .{ .name = "__fixunsxfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixunsxfti_windows_x86_64, .{ .name = "__fixunsxfti", .linkage = common.linkage });
+    } else {
+        @export(__fixunsxfti, .{ .name = "__fixunsxfti", .linkage = common.linkage });
+    }
 }
 
 pub fn __fixunsxfti(a: f80) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixunsxfti_windows_x86_64(a: f80) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(u128, a));
+}
diff --git a/lib/compiler_rt/fixxfti.zig b/lib/compiler_rt/fixxfti.zig
index fb547f411566..9a40ec3d6a13 100644
--- a/lib/compiler_rt/fixxfti.zig
+++ b/lib/compiler_rt/fixxfti.zig
@@ -1,12 +1,23 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixxfti, .{ .name = "__fixxfti", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__fixxfti_windows_x86_64, .{ .name = "__fixxfti", .linkage = common.linkage });
+    } else {
+        @export(__fixxfti, .{ .name = "__fixxfti", .linkage = common.linkage });
+    }
 }
 
-fn __fixxfti(a: f80) callconv(.C) i128 {
+pub fn __fixxfti(a: f80) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v2u64 = @Vector(2, u64);
+
+fn __fixxfti_windows_x86_64(a: f80) callconv(.C) v2u64 {
+    return @bitCast(v2u64, floatToInt(i128, a));
+}
diff --git a/lib/compiler_rt/floattidf.zig b/lib/compiler_rt/floattidf.zig
index 1f1ac2f2effe..31456948e9d8 100644
--- a/lib/compiler_rt/floattidf.zig
+++ b/lib/compiler_rt/floattidf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattidf, .{ .name = "__floattidf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floattidf_windows_x86_64, .{ .name = "__floattidf", .linkage = common.linkage });
+    } else {
+        @export(__floattidf, .{ .name = "__floattidf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floattidf(a: i128) callconv(.C) f64 {
     return intToFloat(f64, a);
 }
+
+fn __floattidf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f64 {
+    return intToFloat(f64, @bitCast(i128, a));
+}
diff --git a/lib/compiler_rt/floattihf.zig b/lib/compiler_rt/floattihf.zig
index c7e45c7d5371..3e33a0bd8a45 100644
--- a/lib/compiler_rt/floattihf.zig
+++ b/lib/compiler_rt/floattihf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattihf, .{ .name = "__floattihf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floattihf_windows_x86_64, .{ .name = "__floattihf", .linkage = common.linkage });
+    } else {
+        @export(__floattihf, .{ .name = "__floattihf", .linkage = common.linkage });
+    }
 }
 
-fn __floattihf(a: i128) callconv(.C) f16 {
+pub fn __floattihf(a: i128) callconv(.C) f16 {
     return intToFloat(f16, a);
 }
+
+fn __floattihf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f16 {
+    return intToFloat(f16, @bitCast(i128, a));
+}
diff --git a/lib/compiler_rt/floattisf.zig b/lib/compiler_rt/floattisf.zig
index 5eb493d09b02..23ff0d16b402 100644
--- a/lib/compiler_rt/floattisf.zig
+++ b/lib/compiler_rt/floattisf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattisf, .{ .name = "__floattisf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floattisf_windows_x86_64, .{ .name = "__floattisf", .linkage = common.linkage });
+    } else {
+        @export(__floattisf, .{ .name = "__floattisf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floattisf(a: i128) callconv(.C) f32 {
     return intToFloat(f32, a);
 }
+
+fn __floattisf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f32 {
+    return intToFloat(f32, @bitCast(i128, a));
+}
diff --git a/lib/compiler_rt/floattitf.zig b/lib/compiler_rt/floattitf.zig
index 0764c2d2c2b2..c44473cc3d50 100644
--- a/lib/compiler_rt/floattitf.zig
+++ b/lib/compiler_rt/floattitf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattitf, .{ .name = "__floattitf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floattitf_windows_x86_64, .{ .name = "__floattitf", .linkage = common.linkage });
+    } else {
+        @export(__floattitf, .{ .name = "__floattitf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floattitf(a: i128) callconv(.C) f128 {
     return intToFloat(f128, a);
 }
+
+fn __floattitf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f128 {
+    return intToFloat(f128, @bitCast(i128, a));
+}
diff --git a/lib/compiler_rt/floattixf.zig b/lib/compiler_rt/floattixf.zig
index def9bef4d5e0..814880b9ab66 100644
--- a/lib/compiler_rt/floattixf.zig
+++ b/lib/compiler_rt/floattixf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattixf, .{ .name = "__floattixf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floattixf_windows_x86_64, .{ .name = "__floattixf", .linkage = common.linkage });
+    } else {
+        @export(__floattixf, .{ .name = "__floattixf", .linkage = common.linkage });
+    }
 }
 
-fn __floattixf(a: i128) callconv(.C) f80 {
+pub fn __floattixf(a: i128) callconv(.C) f80 {
     return intToFloat(f80, a);
 }
+
+fn __floattixf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f80 {
+    return intToFloat(f80, @bitCast(i128, a));
+}
diff --git a/lib/compiler_rt/floatuntidf.zig b/lib/compiler_rt/floatuntidf.zig
index a77a952fe914..a00175d9a9f2 100644
--- a/lib/compiler_rt/floatuntidf.zig
+++ b/lib/compiler_rt/floatuntidf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floatuntidf, .{ .name = "__floatuntidf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floatuntidf_windows_x86_64, .{ .name = "__floatuntidf", .linkage = common.linkage });
+    } else {
+        @export(__floatuntidf, .{ .name = "__floatuntidf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floatuntidf(a: u128) callconv(.C) f64 {
     return intToFloat(f64, a);
 }
+
+fn __floatuntidf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f64 {
+    return intToFloat(f64, @bitCast(u128, a));
+}
diff --git a/lib/compiler_rt/floatuntihf.zig b/lib/compiler_rt/floatuntihf.zig
index 0263b1da98bc..3cf7a32d270c 100644
--- a/lib/compiler_rt/floatuntihf.zig
+++ b/lib/compiler_rt/floatuntihf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floatuntihf, .{ .name = "__floatuntihf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floatuntihf_windows_x86_64, .{ .name = "__floatuntihf", .linkage = common.linkage });
+    } else {
+        @export(__floatuntihf, .{ .name = "__floatuntihf", .linkage = common.linkage });
+    }
 }
 
-fn __floatuntihf(a: u128) callconv(.C) f16 {
+pub fn __floatuntihf(a: u128) callconv(.C) f16 {
     return intToFloat(f16, a);
 }
+
+fn __floatuntihf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f16 {
+    return intToFloat(f16, @bitCast(u128, a));
+}
diff --git a/lib/compiler_rt/floatuntisf.zig b/lib/compiler_rt/floatuntisf.zig
index 3edf63698748..997d57293e7d 100644
--- a/lib/compiler_rt/floatuntisf.zig
+++ b/lib/compiler_rt/floatuntisf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floatuntisf, .{ .name = "__floatuntisf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floatuntisf_windows_x86_64, .{ .name = "__floatuntisf", .linkage = common.linkage });
+    } else {
+        @export(__floatuntisf, .{ .name = "__floatuntisf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floatuntisf(a: u128) callconv(.C) f32 {
     return intToFloat(f32, a);
 }
+
+fn __floatuntisf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f32 {
+    return intToFloat(f32, @bitCast(u128, a));
+}
diff --git a/lib/compiler_rt/floatuntitf.zig b/lib/compiler_rt/floatuntitf.zig
index 1a755cccdb3b..eb5d7037e9be 100644
--- a/lib/compiler_rt/floatuntitf.zig
+++ b/lib/compiler_rt/floatuntitf.zig
@@ -1,13 +1,16 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    if (common.want_ppc_abi) {
-        @export(__floatuntikf, .{ .name = "__floatuntikf", .linkage = common.linkage });
+    const symbol_name = if (common.want_ppc_abi) "__floatuntikf" else "__floatuntitf";
+
+    if (common.want_windows_v2u64_abi) {
+        @export(__floatuntitf_windows_x86_64, .{ .name = symbol_name, .linkage = common.linkage });
     } else {
-        @export(__floatuntitf, .{ .name = "__floatuntitf", .linkage = common.linkage });
+        @export(__floatuntitf, .{ .name = symbol_name, .linkage = common.linkage });
     }
 }
 
@@ -15,6 +18,6 @@ pub fn __floatuntitf(a: u128) callconv(.C) f128 {
     return intToFloat(f128, a);
 }
 
-fn __floatuntikf(a: u128) callconv(.C) f128 {
-    return intToFloat(f128, a);
+fn __floatuntitf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f128 {
+    return intToFloat(f128, @bitCast(u128, a));
 }
diff --git a/lib/compiler_rt/floatuntixf.zig b/lib/compiler_rt/floatuntixf.zig
index 07017d1f5738..724af9507514 100644
--- a/lib/compiler_rt/floatuntixf.zig
+++ b/lib/compiler_rt/floatuntixf.zig
@@ -1,12 +1,21 @@
+const builtin = @import("builtin");
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floatuntixf, .{ .name = "__floatuntixf", .linkage = common.linkage });
+    if (common.want_windows_v2u64_abi) {
+        @export(__floatuntixf_windows_x86_64, .{ .name = "__floatuntixf", .linkage = common.linkage });
+    } else {
+        @export(__floatuntixf, .{ .name = "__floatuntixf", .linkage = common.linkage });
+    }
 }
 
 pub fn __floatuntixf(a: u128) callconv(.C) f80 {
     return intToFloat(f80, a);
 }
+
+fn __floatuntixf_windows_x86_64(a: @Vector(2, u64)) callconv(.C) f80 {
+    return intToFloat(f80, @bitCast(u128, a));
+}
diff --git a/lib/compiler_rt/modti3.zig b/lib/compiler_rt/modti3.zig
index 5fa34938ff9b..9992f716eefd 100644
--- a/lib/compiler_rt/modti3.zig
+++ b/lib/compiler_rt/modti3.zig
@@ -5,27 +5,13 @@
 const std = @import("std");
 const builtin = @import("builtin");
 const udivmod = @import("udivmod.zig").udivmod;
-const arch = builtin.cpu.arch;
 const common = @import("common.zig");
 
 pub const panic = common.panic;
 
 comptime {
-    if (builtin.os.tag == .windows) {
-        switch (arch) {
-            .i386 => {
-                @export(__modti3, .{ .name = "__modti3", .linkage = common.linkage });
-            },
-            .x86_64 => {
-                // The "ti" functions must use Vector(2, u64) parameter types to adhere to the ABI
-                // that LLVM expects compiler-rt to have.
-                @export(__modti3_windows_x86_64, .{ .name = "__modti3", .linkage = common.linkage });
-            },
-            else => {},
-        }
-        if (arch.isAARCH64()) {
-            @export(__modti3, .{ .name = "__modti3", .linkage = common.linkage });
-        }
+    if (common.want_windows_v2u64_abi) {
+        @export(__modti3_windows_x86_64, .{ .name = "__modti3", .linkage = common.linkage });
     } else {
         @export(__modti3, .{ .name = "__modti3", .linkage = common.linkage });
     }
@@ -35,10 +21,10 @@ pub fn __modti3(a: i128, b: i128) callconv(.C) i128 {
     return mod(a, b);
 }
 
-const v128 = @import("std").meta.Vector(2, u64);
+const v2u64 = @Vector(2, u64);
 
-fn __modti3_windows_x86_64(a: v128, b: v128) callconv(.C) v128 {
-    return @bitCast(v128, mod(@bitCast(i128, a), @bitCast(i128, b)));
+fn __modti3_windows_x86_64(a: v2u64, b: v2u64) callconv(.C) v2u64 {
+    return @bitCast(v2u64, mod(@bitCast(i128, a), @bitCast(i128, b)));
 }
 
 inline fn mod(a: i128, b: i128) i128 {
diff --git a/lib/compiler_rt/multi3.zig b/lib/compiler_rt/multi3.zig
index ba41cb79176b..42994a81bda2 100644
--- a/lib/compiler_rt/multi3.zig
+++ b/lib/compiler_rt/multi3.zig
@@ -4,25 +4,14 @@
 
 const std = @import("std");
 const builtin = @import("builtin");
-const arch = builtin.cpu.arch;
 const native_endian = builtin.cpu.arch.endian();
 const common = @import("common.zig");
 
 pub const panic = common.panic;
 
 comptime {
-    if (builtin.os.tag == .windows) {
-        switch (arch) {
-            .i386 => {
-                @export(__multi3, .{ .name = "__multi3", .linkage = common.linkage });
-            },
-            .x86_64 => {
-                // The "ti" functions must use Vector(2, u64) parameter types to adhere to the ABI
-                // that LLVM expects compiler-rt to have.
-                @export(__multi3_windows_x86_64, .{ .name = "__multi3", .linkage = common.linkage });
-            },
-            else => {},
-        }
+    if (common.want_windows_v2u64_abi) {
+        @export(__multi3_windows_x86_64, .{ .name = "__multi3", .linkage = common.linkage });
     } else {
         @export(__multi3, .{ .name = "__multi3", .linkage = common.linkage });
     }
@@ -32,10 +21,10 @@ pub fn __multi3(a: i128, b: i128) callconv(.C) i128 {
     return mul(a, b);
 }
 
-const v128 = @Vector(2, u64);
+const v2u64 = @Vector(2, u64);
 
-fn __multi3_windows_x86_64(a: v128, b: v128) callconv(.C) v128 {
-    return @bitCast(v128, mul(@bitCast(i128, a), @bitCast(i128, b)));
+fn __multi3_windows_x86_64(a: v2u64, b: v2u64) callconv(.C) v2u64 {
+    return @bitCast(v2u64, mul(@bitCast(i128, a), @bitCast(i128, b)));
 }
 
 inline fn mul(a: i128, b: i128) i128 {
diff --git a/lib/compiler_rt/udivmodti4.zig b/lib/compiler_rt/udivmodti4.zig
index 911bf72eedd6..5ccaa787078f 100644
--- a/lib/compiler_rt/udivmodti4.zig
+++ b/lib/compiler_rt/udivmodti4.zig
@@ -1,24 +1,13 @@
 const std = @import("std");
 const builtin = @import("builtin");
 const udivmod = @import("udivmod.zig").udivmod;
-const arch = builtin.cpu.arch;
 const common = @import("common.zig");
 
 pub const panic = common.panic;
 
 comptime {
-    if (builtin.os.tag == .windows) {
-        switch (arch) {
-            .i386 => {
-                @export(__udivmodti4, .{ .name = "__udivmodti4", .linkage = common.linkage });
-            },
-            .x86_64 => {
-                // The "ti" functions must use Vector(2, u64) parameter types to adhere to the ABI
-                // that LLVM expects compiler-rt to have.
-                @export(__udivmodti4_windows_x86_64, .{ .name = "__udivmodti4", .linkage = common.linkage });
-            },
-            else => {},
-        }
+    if (common.want_windows_v2u64_abi) {
+        @export(__udivmodti4_windows_x86_64, .{ .name = "__udivmodti4", .linkage = common.linkage });
     } else {
         @export(__udivmodti4, .{ .name = "__udivmodti4", .linkage = common.linkage });
     }
@@ -28,10 +17,10 @@ pub fn __udivmodti4(a: u128, b: u128, maybe_rem: ?*u128) callconv(.C) u128 {
     return udivmod(u128, a, b, maybe_rem);
 }
 
-const v128 = std.meta.Vector(2, u64);
+const v2u64 = @Vector(2, u64);
 
-fn __udivmodti4_windows_x86_64(a: v128, b: v128, maybe_rem: ?*u128) callconv(.C) v128 {
-    return @bitCast(v128, udivmod(u128, @bitCast(u128, a), @bitCast(u128, b), maybe_rem));
+fn __udivmodti4_windows_x86_64(a: v2u64, b: v2u64, maybe_rem: ?*u128) callconv(.C) v2u64 {
+    return @bitCast(v2u64, udivmod(u128, @bitCast(u128, a), @bitCast(u128, b), maybe_rem));
 }
 
 test {
diff --git a/lib/compiler_rt/udivti3.zig b/lib/compiler_rt/udivti3.zig
index 3e908176bc44..094627ad92d1 100644
--- a/lib/compiler_rt/udivti3.zig
+++ b/lib/compiler_rt/udivti3.zig
@@ -1,27 +1,13 @@
 const std = @import("std");
 const builtin = @import("builtin");
 const udivmod = @import("udivmod.zig").udivmod;
-const arch = builtin.cpu.arch;
 const common = @import("common.zig");
 
 pub const panic = common.panic;
 
 comptime {
-    if (builtin.os.tag == .windows) {
-        switch (arch) {
-            .i386 => {
-                @export(__udivti3, .{ .name = "__udivti3", .linkage = common.linkage });
-            },
-            .x86_64 => {
-                // The "ti" functions must use Vector(2, u64) parameter types to adhere to the ABI
-                // that LLVM expects compiler-rt to have.
-                @export(__udivti3_windows_x86_64, .{ .name = "__udivti3", .linkage = common.linkage });
-            },
-            else => {},
-        }
-        if (arch.isAARCH64()) {
-            @export(__udivti3, .{ .name = "__udivti3", .linkage = common.linkage });
-        }
+    if (common.want_windows_v2u64_abi) {
+        @export(__udivti3_windows_x86_64, .{ .name = "__udivti3", .linkage = common.linkage });
     } else {
         @export(__udivti3, .{ .name = "__udivti3", .linkage = common.linkage });
     }
@@ -31,8 +17,8 @@ pub fn __udivti3(a: u128, b: u128) callconv(.C) u128 {
     return udivmod(u128, a, b, null);
 }
 
-const v128 = std.meta.Vector(2, u64);
+const v2u64 = @Vector(2, u64);
 
-fn __udivti3_windows_x86_64(a: v128, b: v128) callconv(.C) v128 {
-    return @bitCast(v128, udivmod(u128, @bitCast(u128, a), @bitCast(u128, b), null));
+fn __udivti3_windows_x86_64(a: v2u64, b: v2u64) callconv(.C) v2u64 {
+    return @bitCast(v2u64, udivmod(u128, @bitCast(u128, a), @bitCast(u128, b), null));
 }
diff --git a/lib/compiler_rt/umodti3.zig b/lib/compiler_rt/umodti3.zig
index 65058a599e9d..a9aba96b7e4f 100644
--- a/lib/compiler_rt/umodti3.zig
+++ b/lib/compiler_rt/umodti3.zig
@@ -1,27 +1,13 @@
 const std = @import("std");
 const builtin = @import("builtin");
 const udivmod = @import("udivmod.zig").udivmod;
-const arch = builtin.cpu.arch;
 const common = @import("common.zig");
 
 pub const panic = common.panic;
 
 comptime {
-    if (builtin.os.tag == .windows) {
-        switch (arch) {
-            .i386 => {
-                @export(__umodti3, .{ .name = "__umodti3", .linkage = common.linkage });
-            },
-            .x86_64 => {
-                // The "ti" functions must use Vector(2, u64) parameter types to adhere to the ABI
-                // that LLVM expects compiler-rt to have.
-                @export(__umodti3_windows_x86_64, .{ .name = "__umodti3", .linkage = common.linkage });
-            },
-            else => {},
-        }
-        if (arch.isAARCH64()) {
-            @export(__umodti3, .{ .name = "__umodti3", .linkage = common.linkage });
-        }
+    if (common.want_windows_v2u64_abi) {
+        @export(__umodti3_windows_x86_64, .{ .name = "__umodti3", .linkage = common.linkage });
     } else {
         @export(__umodti3, .{ .name = "__umodti3", .linkage = common.linkage });
     }
@@ -33,10 +19,10 @@ pub fn __umodti3(a: u128, b: u128) callconv(.C) u128 {
     return r;
 }
 
-const v128 = std.meta.Vector(2, u64);
+const v2u64 = @Vector(2, u64);
 
-fn __umodti3_windows_x86_64(a: v128, b: v128) callconv(.C) v128 {
+fn __umodti3_windows_x86_64(a: v2u64, b: v2u64) callconv(.C) v2u64 {
     var r: u128 = undefined;
     _ = udivmod(u128, @bitCast(u128, a), @bitCast(u128, b), &r);
-    return @bitCast(v128, r);
+    return @bitCast(v2u64, r);
 }
diff --git a/lib/std/fmt.zig b/lib/std/fmt.zig
index 90e70a7c4163..f6b98be44dbc 100644
--- a/lib/std/fmt.zig
+++ b/lib/std/fmt.zig
@@ -2284,10 +2284,6 @@ test "float.hexadecimal.precision" {
 }
 
 test "float.decimal" {
-    if (builtin.zig_backend == .stage1 and builtin.os.tag == .windows) {
-        // https://github.com/ziglang/zig/issues/12063
-        return error.SkipZigTest;
-    }
     try expectFmt("f64: 152314000000000000000000000000", "f64: {d}", .{@as(f64, 1.52314e+29)});
     try expectFmt("f32: 0", "f32: {d}", .{@as(f32, 0.0)});
     try expectFmt("f32: 0", "f32: {d:.0}", .{@as(f32, 0.0)});
@@ -2311,10 +2307,6 @@ test "float.decimal" {
 }
 
 test "float.libc.sanity" {
-    if (builtin.zig_backend == .stage1 and builtin.os.tag == .windows) {
-        // https://github.com/ziglang/zig/issues/12063
-        return error.SkipZigTest;
-    }
     try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @bitCast(f32, @as(u32, 916964781)))});
     try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @bitCast(f32, @as(u32, 925353389)))});
     try expectFmt("f64: 0.10000", "f64: {d:.5}", .{@as(f64, @bitCast(f32, @as(u32, 1036831278)))});
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index acd571a58bd1..b4e90503a46e 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -4802,7 +4802,7 @@ pub const FuncGen = struct {
         const operand_bits = @intCast(u16, operand_scalar_ty.bitSize(target));
         const rt_int_bits = compilerRtIntBits(operand_bits);
         const rt_int_ty = self.context.intType(rt_int_bits);
-        const extended = e: {
+        var extended = e: {
             if (operand_scalar_ty.isSignedInt()) {
                 break :e self.builder.buildSExtOrBitCast(operand, rt_int_ty, "");
             } else {
@@ -4819,7 +4819,16 @@ pub const FuncGen = struct {
             compiler_rt_operand_abbrev,
             compiler_rt_dest_abbrev,
         }) catch unreachable;
-        const param_types = [1]*const llvm.Type{rt_int_ty};
+
+        var param_types = [1]*const llvm.Type{rt_int_ty};
+        if (rt_int_bits == 128 and (target.os.tag == .windows and target.cpu.arch == .x86_64)) {
+            // On Windows x86-64, "ti" functions must use Vector(2, u64) instead of the standard
+            // i128 calling convention to adhere to the ABI that LLVM expects compiler-rt to have.
+            const v2i64 = self.context.intType(64).vectorType(2);
+            extended = self.builder.buildBitCast(extended, v2i64, "");
+            param_types = [1]*const llvm.Type{v2i64};
+        }
+
         const libc_fn = self.getLibcFunction(fn_name, &param_types, dest_llvm_ty);
         const params = [1]*const llvm.Value{extended};
 
@@ -4851,7 +4860,12 @@ pub const FuncGen = struct {
         }
 
         const rt_int_bits = compilerRtIntBits(@intCast(u16, dest_scalar_ty.bitSize(target)));
-        const libc_ret_ty = self.context.intType(rt_int_bits);
+        const ret_ty = self.context.intType(rt_int_bits);
+        const libc_ret_ty = if (rt_int_bits == 128 and (target.os.tag == .windows and target.cpu.arch == .x86_64)) b: {
+            // On Windows x86-64, "ti" functions must use Vector(2, u64) instead of the standard
+            // i128 calling convention to adhere to the ABI that LLVM expects compiler-rt to have.
+            break :b self.context.intType(64).vectorType(2);
+        } else ret_ty;
 
         const operand_bits = operand_scalar_ty.floatBits(target);
         const compiler_rt_operand_abbrev = compilerRtFloatAbbrev(operand_bits);
@@ -4871,13 +4885,11 @@ pub const FuncGen = struct {
         const libc_fn = self.getLibcFunction(fn_name, &param_types, libc_ret_ty);
         const params = [1]*const llvm.Value{operand};
 
-        const result = self.builder.buildCall(libc_fn, &params, params.len, .C, .Auto, "");
-
-        if (libc_ret_ty == dest_llvm_ty) {
-            return result;
-        }
+        var result = self.builder.buildCall(libc_fn, &params, params.len, .C, .Auto, "");
 
-        return self.builder.buildTrunc(result, dest_llvm_ty, "");
+        if (libc_ret_ty != ret_ty) result = self.builder.buildBitCast(result, ret_ty, "");
+        if (ret_ty != dest_llvm_ty) result = self.builder.buildTrunc(result, dest_llvm_ty, "");
+        return result;
     }
 
     fn airSliceField(self: *FuncGen, inst: Air.Inst.Index, index: c_uint) !?*const llvm.Value {
@@ -6490,8 +6502,15 @@ pub const FuncGen = struct {
                     const one = int_llvm_ty.constInt(1, .False);
                     const shift_amt = int_llvm_ty.constInt(float_bits - 1, .False);
                     const sign_mask = one.constShl(shift_amt);
-                    const bitcasted_operand = self.builder.buildBitCast(params[0], int_llvm_ty, "");
-                    const result = self.builder.buildXor(bitcasted_operand, sign_mask, "");
+                    const result = if (ty.zigTypeTag() == .Vector) blk: {
+                        const splat_sign_mask = self.builder.buildVectorSplat(ty.vectorLen(), sign_mask, "");
+                        const cast_ty = int_llvm_ty.vectorType(ty.vectorLen());
+                        const bitcasted_operand = self.builder.buildBitCast(params[0], cast_ty, "");
+                        break :blk self.builder.buildXor(bitcasted_operand, splat_sign_mask, "");
+                    } else blk: {
+                        const bitcasted_operand = self.builder.buildBitCast(params[0], int_llvm_ty, "");
+                        break :blk self.builder.buildXor(bitcasted_operand, sign_mask, "");
+                    };
                     return self.builder.buildBitCast(result, llvm_ty, "");
                 },
                 .add, .sub, .div, .mul => FloatOpStrat{
diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
index 9c8269549b8c..81e5208e9190 100644
--- a/src/stage1/codegen.cpp
+++ b/src/stage1/codegen.cpp
@@ -3371,14 +3371,12 @@ static LLVMValueRef add_icmp(CodeGen *g, LLVMValueRef val, Icmp kind) {
 }
 
 static LLVMValueRef gen_soft_int_to_float_op(CodeGen *g, LLVMValueRef value_ref, ZigType *operand_type, ZigType *result_type) {
-    uint32_t vector_len = operand_type->id == ZigTypeIdVector ? operand_type->data.vector.len : 0;
-
     // Handle integers of non-pot bitsize by widening them.
     const size_t bitsize = operand_type->data.integral.bit_count;
     const bool is_signed = operand_type->data.integral.is_signed;
     if (bitsize < 32 || !is_power_of_2(bitsize)) {
         const size_t wider_bitsize = bitsize < 32 ? 32 : round_to_next_power_of_2(bitsize);
-        ZigType *const wider_type = get_int_type(g, is_signed, wider_bitsize);
+        ZigType *wider_type = get_int_type(g, is_signed, wider_bitsize);
         value_ref = gen_widen_or_shorten(g, false, operand_type, wider_type, value_ref);
         operand_type = wider_type;
     }
@@ -3395,35 +3393,22 @@ static LLVMValueRef gen_soft_int_to_float_op(CodeGen *g, LLVMValueRef value_ref,
     }
 
     int param_count = 1;
-    LLVMValueRef func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, result_type->llvm_type);
-
-    LLVMValueRef result;
-    if (vector_len == 0) {
-        LLVMValueRef params[1] = {value_ref};
-        result = LLVMBuildCall(g->builder, func_ref, params, param_count, "");
+    LLVMValueRef func_ref;
+    if ((operand_type->data.integral.bit_count == 128) && (g->zig_target->os == OsWindows) && (g->zig_target->arch == ZigLLVM_x86_64)) {
+        // On Windows x86-64, "ti" functions must use Vector(2, u64) instead of the standard i128 calling
+        // convention to adhere to the ABI that LLVM expects compiler-rt to have.
+        LLVMTypeRef v2i64 = LLVMVectorType(LLVMInt64Type(), 2);
+        value_ref = LLVMBuildBitCast(g->builder, value_ref, v2i64, "");
+        func_ref = get_soft_float_fn(g, fn_name, param_count, v2i64, result_type->llvm_type);
     } else {
-        ZigType *alloca_ty = operand_type;
-        result = build_alloca(g, alloca_ty, "", 0);
-
-        LLVMTypeRef usize_ref = g->builtin_types.entry_usize->llvm_type;
-        for (uint32_t i = 0; i < vector_len; i++) {
-            LLVMValueRef index_value = LLVMConstInt(usize_ref, i, false);
-            LLVMValueRef params[1] = {
-                LLVMBuildExtractElement(g->builder, value_ref, index_value, ""),
-            };
-            LLVMValueRef call_result = LLVMBuildCall(g->builder, func_ref, params, param_count, "");
-            LLVMBuildInsertElement(g->builder, LLVMBuildLoad(g->builder, result, ""),
-                call_result, index_value, "");
-        }
-
-        result = LLVMBuildLoad(g->builder, result, "");
+        func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, result_type->llvm_type);
     }
-    return result;
+
+    LLVMValueRef params[1] = {value_ref};
+    return LLVMBuildCall(g->builder, func_ref, params, param_count, "");
 }
 
 static LLVMValueRef gen_soft_float_to_int_op(CodeGen *g, LLVMValueRef value_ref, ZigType *operand_type, ZigType *result_type) {
-    uint32_t vector_len = operand_type->id == ZigTypeIdVector ? operand_type->data.vector.len : 0;
-
     // Handle integers of non-pot bitsize by truncating a sufficiently wide pot integer
     const size_t bitsize = result_type->data.integral.bit_count;
     const bool is_signed = result_type->data.integral.is_signed;
@@ -3445,46 +3430,41 @@ static LLVMValueRef gen_soft_float_to_int_op(CodeGen *g, LLVMValueRef value_ref,
     }
 
     int param_count = 1;
-    LLVMValueRef func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, wider_type->llvm_type);
-
-    LLVMValueRef result;
-    if (vector_len == 0) {
-        LLVMValueRef params[1] = {value_ref};
-        result = LLVMBuildCall(g->builder, func_ref, params, param_count, "");
+    LLVMValueRef func_ref;
+    if ((wider_type->data.integral.bit_count == 128) && (g->zig_target->os == OsWindows) && (g->zig_target->arch == ZigLLVM_x86_64)) {
+        // On Windows x86-64, "ti" functions must use Vector(2, u64) instead of the standard i128 calling
+        // convention to adhere to the ABI that LLVM expects compiler-rt to have.
+        LLVMTypeRef v2i64 = LLVMVectorType(LLVMInt64Type(), 2);
+        func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, v2i64);
     } else {
-        ZigType *alloca_ty = operand_type;
-        result = build_alloca(g, alloca_ty, "", 0);
+        func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, wider_type->llvm_type);
+    }
 
-        LLVMTypeRef usize_ref = g->builtin_types.entry_usize->llvm_type;
-        for (uint32_t i = 0; i < vector_len; i++) {
-            LLVMValueRef index_value = LLVMConstInt(usize_ref, i, false);
-            LLVMValueRef params[1] = {
-                LLVMBuildExtractElement(g->builder, value_ref, index_value, ""),
-            };
-            LLVMValueRef call_result = LLVMBuildCall(g->builder, func_ref, params, param_count, "");
-            LLVMBuildInsertElement(g->builder, LLVMBuildLoad(g->builder, result, ""),
-                call_result, index_value, "");
-        }
+    LLVMValueRef params[1] = {value_ref};
+    LLVMValueRef result = LLVMBuildCall(g->builder, func_ref, params, param_count, "");
 
-        result = LLVMBuildLoad(g->builder, result, "");
+    if ((wider_type->data.integral.bit_count == 128) && (g->zig_target->os == OsWindows) && (g->zig_target->arch == ZigLLVM_x86_64)) {
+        result = LLVMBuildBitCast(g->builder, result, wider_type->llvm_type, "");
     }
 
     // Handle integers of non-pot bitsize by shortening them on the output
     if (result_type != wider_type) {
-        return gen_widen_or_shorten(g, false, wider_type, result_type, result);
+        result = gen_widen_or_shorten(g, false, wider_type, result_type, result); 
     }
+
     return result;
 }
 
 static LLVMValueRef gen_soft_float_bin_op(CodeGen *g, LLVMValueRef op1_value, LLVMValueRef op2_value, ZigType *operand_type, IrBinOp op_id) {
     uint32_t vector_len = operand_type->id == ZigTypeIdVector ? operand_type->data.vector.len : 0;
 
-    LLVMTypeRef return_type = operand_type->llvm_type;
     int param_count = 2;
 
-    const char *compiler_rt_type_abbrev = get_compiler_rt_type_abbrev(operand_type);
-    const char *math_float_prefix = libc_float_prefix(g, operand_type);
-    const char *math_float_suffix = libc_float_suffix(g, operand_type);
+    ZigType *operand_scalar_type = (operand_type->id == ZigTypeIdVector) ? operand_type->data.vector.elem_type : operand_type;
+    LLVMTypeRef return_scalar_type = operand_scalar_type->llvm_type;
+    const char *compiler_rt_type_abbrev = get_compiler_rt_type_abbrev(operand_scalar_type);
+    const char *math_float_prefix = libc_float_prefix(g, operand_scalar_type);
+    const char *math_float_suffix = libc_float_suffix(g, operand_scalar_type);
 
     char fn_name[64];
     Icmp res_icmp = NONE;
@@ -3511,32 +3491,32 @@ static LLVMValueRef gen_soft_float_bin_op(CodeGen *g, LLVMValueRef op1_value, LL
         case IrBinOpShlSat:
             zig_unreachable();
         case IrBinOpCmpEq:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__eq%sf2", compiler_rt_type_abbrev);
             res_icmp = EQ_ZERO;
             break;
         case IrBinOpCmpNotEq:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__ne%sf2", compiler_rt_type_abbrev);
             res_icmp = NE_ZERO;
             break;
         case IrBinOpCmpLessOrEq:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__le%sf2", compiler_rt_type_abbrev);
             res_icmp = LE_ZERO;
             break;
         case IrBinOpCmpLessThan:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__le%sf2", compiler_rt_type_abbrev);
             res_icmp = EQ_NEG;
             break;
         case IrBinOpCmpGreaterOrEq:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__ge%sf2", compiler_rt_type_abbrev);
             res_icmp = GE_ZERO;
             break;
         case IrBinOpCmpGreaterThan:
-            return_type = g->builtin_types.entry_i32->llvm_type;
+            return_scalar_type = g->builtin_types.entry_i32->llvm_type;
             snprintf(fn_name, sizeof(fn_name), "__ge%sf2", compiler_rt_type_abbrev);
             res_icmp = EQ_ONE;
             break;
@@ -3569,7 +3549,7 @@ static LLVMValueRef gen_soft_float_bin_op(CodeGen *g, LLVMValueRef op1_value, LL
             zig_unreachable();
     }
 
-    LLVMValueRef func_ref = get_soft_float_fn(g, fn_name, param_count, operand_type->llvm_type, return_type);
+    LLVMValueRef func_ref = get_soft_float_fn(g, fn_name, param_count, operand_scalar_type->llvm_type, return_scalar_type);
 
     LLVMValueRef result;
     if (vector_len == 0) {
diff --git a/test/behavior/vector.zig b/test/behavior/vector.zig
index eb4676310d74..c13db2e26271 100644
--- a/test/behavior/vector.zig
+++ b/test/behavior/vector.zig
@@ -101,18 +101,20 @@ test "vector float operators" {
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
 
-    const S = struct {
-        fn doTheTest() !void {
-            var v: @Vector(4, f32) = [4]f32{ 10, 20, 30, 40 };
-            var x: @Vector(4, f32) = [4]f32{ 1, 2, 3, 4 };
-            try expect(mem.eql(f32, &@as([4]f32, v + x), &[4]f32{ 11, 22, 33, 44 }));
-            try expect(mem.eql(f32, &@as([4]f32, v - x), &[4]f32{ 9, 18, 27, 36 }));
-            try expect(mem.eql(f32, &@as([4]f32, v * x), &[4]f32{ 10, 40, 90, 160 }));
-            try expect(mem.eql(f32, &@as([4]f32, -x), &[4]f32{ -1, -2, -3, -4 }));
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
+    inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
+        const S = struct {
+            fn doTheTest() !void {
+                var v: @Vector(4, T) = [4]T{ 10, 20, 30, 40 };
+                var x: @Vector(4, T) = [4]T{ 1, 2, 3, 4 };
+                try expect(mem.eql(T, &@as([4]T, v + x), &[4]T{ 11, 22, 33, 44 }));
+                try expect(mem.eql(T, &@as([4]T, v - x), &[4]T{ 9, 18, 27, 36 }));
+                try expect(mem.eql(T, &@as([4]T, v * x), &[4]T{ 10, 40, 90, 160 }));
+                try expect(mem.eql(T, &@as([4]T, -x), &[4]T{ -1, -2, -3, -4 }));
+            }
+        };
+        try S.doTheTest();
+        comptime try S.doTheTest();
+    }
 }
 
 test "vector bit operators" {