From 6a3659c4e005d9730fb824b77b416ef33200dbfe Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 16 Oct 2021 13:31:54 +0200
Subject: [PATCH 1/6] big.int: 2s-complement binary wrapping not

---
 lib/std/math/big/int.zig      | 23 ++++++++++++++++++++--
 lib/std/math/big/int_test.zig | 36 +++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/lib/std/math/big/int.zig b/lib/std/math/big/int.zig
index 8082e656e1..ddcda677d6 100644
--- a/lib/std/math/big/int.zig
+++ b/lib/std/math/big/int.zig
@@ -825,7 +825,7 @@ pub const Mutable = struct {
     ///
     /// Asserts there is enough memory to fit the result. The upper bound Limb count is
     /// r is `calcTwosCompLimbCount(bit_count)`.
-    pub fn shiftLeftSat(r: *Mutable, a: Const, shift: usize, signedness: std.builtin.Signedness, bit_count: usize) void {
+    pub fn shiftLeftSat(r: *Mutable, a: Const, shift: usize, signedness: Signedness, bit_count: usize) void {
         // Special case: When the argument is negative, but the result is supposed to be unsigned,
         // return 0 in all cases.
         if (!a.positive and signedness == .unsigned) {
@@ -906,6 +906,17 @@ pub const Mutable = struct {
         r.positive = a.positive;
     }
 
+    /// r = ~a under 2s complement wrapping semantics.
+    /// r may alias with a.
+    ///
+    /// Assets that r has enough limbs to store the result. The upper bound Limb count is
+    /// r is `calcTwosCompLimbCount(bit_count)`.
+    pub fn bitNotWrap(r: *Mutable, a: Const, signedness: Signedness, bit_count: usize) void {
+        r.copy(a.negate());
+        const negative_one = Const{ .limbs = &.{1}, .positive = false };
+        r.addWrap(r.toConst(), negative_one, signedness, bit_count);
+    }
+
     /// r = a | b under 2s complement semantics.
     /// r may alias with a or b.
     ///
@@ -2455,7 +2466,7 @@ pub const Managed = struct {
     }
 
     /// r = a <<| shift with 2s-complement saturating semantics.
-    pub fn shiftLeftSat(r: *Managed, a: Managed, shift: usize, signedness: std.builtin.Signedness, bit_count: usize) !void {
+    pub fn shiftLeftSat(r: *Managed, a: Managed, shift: usize, signedness: Signedness, bit_count: usize) !void {
         try r.ensureTwosCompCapacity(bit_count);
         var m = r.toMutable();
         m.shiftLeftSat(a.toConst(), shift, signedness, bit_count);
@@ -2476,6 +2487,14 @@ pub const Managed = struct {
         r.setMetadata(m.positive, m.len);
     }
 
+    /// r = ~a under 2s-complement wrapping semantics.
+    pub fn bitNotWrap(r: *Managed, a: Managed, signedness: Signedness, bit_count: usize) !void {
+        try r.ensureTwosCompCapacity(bit_count);
+        var m = r.toMutable();
+        m.bitNotWrap(a.toConst(), signedness, bit_count);
+        r.setMetadata(m.positive, m.len);
+    }
+
     /// r = a | b
     ///
     /// a and b are zero-extended to the longer of a or b.
diff --git a/lib/std/math/big/int_test.zig b/lib/std/math/big/int_test.zig
index a7e3186632..78762d4fca 100644
--- a/lib/std/math/big/int_test.zig
+++ b/lib/std/math/big/int_test.zig
@@ -1866,6 +1866,42 @@ test "big.int sat shift-left signed multi negative" {
     try testing.expect((try a.to(SignedDoubleLimb)) == @as(SignedDoubleLimb, x) <<| shift);
 }
 
+test "big.int bitNotWrap unsigned simple" {
+    var a = try Managed.initSet(testing.allocator, 123);
+    defer a.deinit();
+
+    try a.bitNotWrap(a, .unsigned, 10);
+
+    try testing.expect((try a.to(u10)) == ~@as(u10, 123));
+}
+
+test "big.int bitNotWrap unsigned multi" {
+    var a = try Managed.initSet(testing.allocator, 0);
+    defer a.deinit();
+
+    try a.bitNotWrap(a, .unsigned, @bitSizeOf(DoubleLimb));
+
+    try testing.expect((try a.to(DoubleLimb)) == maxInt(DoubleLimb));
+}
+
+test "big.int bitNotWrap signed simple" {
+    var a = try Managed.initSet(testing.allocator, -456);
+    defer a.deinit();
+
+    try a.bitNotWrap(a, .signed, 11);
+
+    try testing.expect((try a.to(i11)) == ~@as(i11, -456));
+}
+
+test "big.int bitNotWrap signed multi" {
+    var a = try Managed.initSet(testing.allocator, 0);
+    defer a.deinit();
+
+    try a.bitNotWrap(a, .signed, @bitSizeOf(SignedDoubleLimb));
+
+    try testing.expect((try a.to(SignedDoubleLimb)) == -1);
+}
+
 test "big.int bitwise and simple" {
     var a = try Managed.initSet(testing.allocator, 0xffffffff11111111);
     defer a.deinit();

From 9336a87452eda87c19cb707484d0b6dfb4140b57 Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 16 Oct 2021 14:47:55 +0200
Subject: [PATCH 2/6] stage2: bitNot

---
 src/Sema.zig                  | 38 +++++++++++++++++++++++++++++++++--
 src/value.zig                 | 26 ++++++++++++++++++++++++
 test/behavior/math.zig        | 14 +++++++++++++
 test/behavior/math_stage1.zig | 14 -------------
 4 files changed, 76 insertions(+), 16 deletions(-)

diff --git a/src/Sema.zig b/src/Sema.zig
index 229ae054b2..6ad423a8e8 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -6627,8 +6627,42 @@ fn zirBitNot(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.
     const tracy = trace(@src());
     defer tracy.end();
 
-    _ = inst;
-    return sema.fail(block, sema.src, "TODO implement zirBitNot", .{});
+    const inst_data = sema.code.instructions.items(.data)[inst].un_node;
+    const src = inst_data.src();
+    const operand_src = src; // TODO put this on the operand, not the '~'
+
+    const operand = sema.resolveInst(inst_data.operand);
+    const operand_type = sema.typeOf(operand);
+    const scalar_type = operand_type.scalarType();
+
+    if (scalar_type.zigTypeTag() != .Int) {
+        return sema.fail(block, src, "unable to perform binary not operation on type '{}'", .{operand_type});
+    }
+
+    if (try sema.resolveMaybeUndefVal(block, operand_src, operand)) |val| {
+        const target = sema.mod.getTarget();
+        if (val.isUndef()) {
+            return sema.addConstUndef(scalar_type);
+        } else if (operand_type.zigTypeTag() == .Vector) {
+            const vec_len = operand_type.arrayLen();
+            var elem_val_buf: Value.ElemValueBuffer = undefined;
+            const elems = try sema.arena.alloc(Value, vec_len);
+            for (elems) |*elem, i| {
+                const elem_val = val.elemValueBuffer(i, &elem_val_buf);
+                elem.* = try elem_val.bitwiseNot(scalar_type, sema.arena, target);
+            }
+            return sema.addConstant(
+                operand_type,
+                try Value.Tag.array.create(sema.arena, elems),
+            );
+        } else {
+            const result_val = try val.bitwiseNot(scalar_type, sema.arena, target);
+            return sema.addConstant(scalar_type, result_val);
+        }
+    }
+
+    try sema.requireRuntimeBlock(block, src);
+    return block.addTyOp(.not, operand_type, operand);
 }
 
 fn zirArrayCat(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
diff --git a/src/value.zig b/src/value.zig
index 127c6c27b4..030ee8f783 100644
--- a/src/value.zig
+++ b/src/value.zig
@@ -2081,6 +2081,32 @@ pub const Value = extern union {
         };
     }
 
+    /// operands must be integers; handles undefined.
+    pub fn bitwiseNot(val: Value, ty: Type, arena: *Allocator, target: Target) !Value {
+        if (val.isUndef()) return Value.initTag(.undef);
+
+        const info = ty.intInfo(target);
+
+        // TODO is this a performance issue? maybe we should try the operation without
+        // resorting to BigInt first.
+        var val_space: Value.BigIntSpace = undefined;
+        const val_bigint = val.toBigInt(&val_space);
+        const limbs = try arena.alloc(
+            std.math.big.Limb,
+            std.math.big.int.calcTwosCompLimbCount(info.bits),
+        );
+
+        var result_bigint = BigIntMutable{ .limbs = limbs, .positive = undefined, .len = undefined };
+        result_bigint.bitNotWrap(val_bigint, info.signedness, info.bits);
+        const result_limbs = result_bigint.limbs[0..result_bigint.len];
+
+        if (result_bigint.positive) {
+            return Value.Tag.int_big_positive.create(arena, result_limbs);
+        } else {
+            return Value.Tag.int_big_negative.create(arena, result_limbs);
+        }
+    }
+
     /// operands must be integers; handles undefined. 
     pub fn bitwiseAnd(lhs: Value, rhs: Value, arena: *Allocator) !Value {
         if (lhs.isUndef() or rhs.isUndef()) return Value.initTag(.undef);
diff --git a/test/behavior/math.zig b/test/behavior/math.zig
index 56fbdc124d..8ca757b0cc 100644
--- a/test/behavior/math.zig
+++ b/test/behavior/math.zig
@@ -235,3 +235,17 @@ test "comptime_int param and return" {
 fn comptimeAdd(comptime a: comptime_int, comptime b: comptime_int) comptime_int {
     return a + b;
 }
+
+test "binary not" {
+    try expect(comptime x: {
+        break :x ~@as(u16, 0b1010101010101010) == 0b0101010101010101;
+    });
+    try expect(comptime x: {
+        break :x ~@as(u64, 2147483647) == 18446744071562067968;
+    });
+    try testBinaryNot(0b1010101010101010);
+}
+
+fn testBinaryNot(x: u16) !void {
+    try expect(~x == 0b0101010101010101);
+}
diff --git a/test/behavior/math_stage1.zig b/test/behavior/math_stage1.zig
index f0c160ebc4..caec185414 100644
--- a/test/behavior/math_stage1.zig
+++ b/test/behavior/math_stage1.zig
@@ -219,20 +219,6 @@ const DivResult = struct {
     remainder: u64,
 };
 
-test "binary not" {
-    try expect(comptime x: {
-        break :x ~@as(u16, 0b1010101010101010) == 0b0101010101010101;
-    });
-    try expect(comptime x: {
-        break :x ~@as(u64, 2147483647) == 18446744071562067968;
-    });
-    try testBinaryNot(0b1010101010101010);
-}
-
-fn testBinaryNot(x: u16) !void {
-    try expect(~x == 0b0101010101010101);
-}
-
 test "small int addition" {
     var x: u2 = 0;
     try expect(x == 0);

From d193ba9843324dcaf239220df8db63ebe3adf67e Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 16 Oct 2021 17:23:30 +0200
Subject: [PATCH 3/6] stage2: array->vector coercion

---
 src/Sema.zig                  | 51 ++++++++++++++++++++---------------
 src/codegen/llvm.zig          | 37 +++++++++++++++++++++++++
 src/codegen/llvm/bindings.zig |  9 +++++++
 3 files changed, 75 insertions(+), 22 deletions(-)

diff --git a/src/Sema.zig b/src/Sema.zig
index 6ad423a8e8..b9c296bd4b 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -11653,7 +11653,11 @@ fn coerce(
             else => {},
         },
         .Array => switch (inst_ty.zigTypeTag()) {
-            .Vector => return sema.coerceVectorToArray(block, dest_ty, dest_ty_src, inst, inst_src),
+            .Vector => return sema.coerceVectorInMemory(block, dest_ty, dest_ty_src, inst, inst_src),
+            else => {},
+        },
+        .Vector => switch (inst_ty.zigTypeTag()) {
+            .Array => return sema.coerceVectorInMemory(block, dest_ty, dest_ty_src, inst, inst_src),
             else => {},
         },
         else => {},
@@ -12237,46 +12241,49 @@ fn coerceEnumToUnion(
     return sema.failWithOwnedErrorMsg(msg);
 }
 
-fn coerceVectorToArray(
+// Coerces vectors/arrays which have the same in-memory layout. This can be used for
+// both coercing from and to vectors.
+fn coerceVectorInMemory(
     sema: *Sema,
     block: *Block,
-    array_ty: Type,
-    array_ty_src: LazySrcLoc,
-    vector: Air.Inst.Ref,
-    vector_src: LazySrcLoc,
+    dest_ty: Type,
+    dest_ty_src: LazySrcLoc,
+    inst: Air.Inst.Ref,
+    inst_src: LazySrcLoc,
 ) !Air.Inst.Ref {
-    const vector_ty = sema.typeOf(vector);
-    const array_len = array_ty.arrayLen();
-    const vector_len = vector_ty.arrayLen();
-    if (array_len != vector_len) {
+    const inst_ty = sema.typeOf(inst);
+    const inst_len = inst_ty.arrayLen();
+    const dest_len = dest_ty.arrayLen();
+
+    if (dest_len != inst_len) {
         const msg = msg: {
-            const msg = try sema.errMsg(block, vector_src, "expected {}, found {}", .{
-                array_ty, vector_ty,
+            const msg = try sema.errMsg(block, inst_src, "expected {}, found {}", .{
+                dest_ty, inst_ty,
             });
             errdefer msg.destroy(sema.gpa);
-            try sema.errNote(block, array_ty_src, msg, "array has length {d}", .{array_len});
-            try sema.errNote(block, vector_src, msg, "vector has length {d}", .{vector_len});
+            try sema.errNote(block, dest_ty_src, msg, "destination has length {d}", .{dest_len});
+            try sema.errNote(block, inst_src, msg, "source has length {d}", .{inst_len});
             break :msg msg;
         };
         return sema.failWithOwnedErrorMsg(msg);
     }
 
     const target = sema.mod.getTarget();
-    const array_elem_ty = array_ty.childType();
-    const vector_elem_ty = vector_ty.childType();
-    const in_memory_result = coerceInMemoryAllowed(array_elem_ty, vector_elem_ty, false, target);
+    const dest_elem_ty = dest_ty.childType();
+    const inst_elem_ty = inst_ty.childType();
+    const in_memory_result = coerceInMemoryAllowed(dest_elem_ty, inst_elem_ty, false, target);
     if (in_memory_result != .ok) {
         // TODO recursive error notes for coerceInMemoryAllowed failure
-        return sema.fail(block, vector_src, "expected {}, found {}", .{ array_ty, vector_ty });
+        return sema.fail(block, inst_src, "expected {}, found {}", .{ dest_ty, inst_ty });
     }
 
-    if (try sema.resolveMaybeUndefVal(block, vector_src, vector)) |vector_val| {
+    if (try sema.resolveMaybeUndefVal(block, inst_src, inst)) |inst_val| {
         // These types share the same comptime value representation.
-        return sema.addConstant(array_ty, vector_val);
+        return sema.addConstant(dest_ty, inst_val);
     }
 
-    try sema.requireRuntimeBlock(block, vector_src);
-    return block.addTyOp(.bitcast, array_ty, vector);
+    try sema.requireRuntimeBlock(block, inst_src);
+    return block.addTyOp(.bitcast, dest_ty, inst);
 }
 
 fn coerceErrSetToAnyError(
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 4349fce4d9..70442729ba 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -2889,6 +2889,43 @@ pub const FuncGen = struct {
                 }
             }
             return array_ptr;
+        } else if (operand_ty.zigTypeTag() == .Array and inst_ty.zigTypeTag() == .Vector) {
+            const target = self.dg.module.getTarget();
+            const elem_ty = operand_ty.childType();
+            const llvm_vector_ty = try self.dg.llvmType(inst_ty);
+            if (!isByRef(operand_ty)) {
+                return self.dg.todo("implement bitcast non-ref array to vector", .{});
+            }
+
+            const bitcast_ok = elem_ty.bitSize(target) == elem_ty.abiSize(target) * 8;
+            if (bitcast_ok) {
+                const llvm_vector_ptr_ty = llvm_vector_ty.pointerType(0);
+                const casted_ptr = self.builder.buildBitCast(operand, llvm_vector_ptr_ty, "");
+                const vector = self.builder.buildLoad(casted_ptr, "");
+                // The array is aligned to the element's alignment, while the vector might have a completely
+                // different alignment. This means we need to enforce the alignment of this load.
+                vector.setAlignment(elem_ty.abiAlignment(target));
+                return vector;
+            } else {
+                // If the ABI size of the element type is not evenly divisible by size in bits;
+                // a simple bitcast will not work, and we fall back to extractelement.
+                const llvm_usize = try self.dg.llvmType(Type.usize);
+                const llvm_u32 = self.context.intType(32);
+                const zero = llvm_usize.constNull();
+                const vector_len = operand_ty.arrayLen();
+                var vector = llvm_vector_ty.getUndef();
+                var i: u64 = 0;
+                while (i < vector_len) : (i += 1) {
+                    const index_usize = llvm_usize.constInt(i, .False);
+                    const index_u32 = llvm_u32.constInt(i, .False);
+                    const indexes: [2]*const llvm.Value = .{ zero, index_usize };
+                    const elem_ptr = self.builder.buildInBoundsGEP(operand, &indexes, indexes.len, "");
+                    const elem = self.builder.buildLoad(elem_ptr, "");
+                    vector = self.builder.buildInsertElement(vector, elem, index_u32, "");
+                }
+
+                return vector;
+            }
         }
 
         return self.builder.buildBitCast(operand, llvm_dest_ty, "");
diff --git a/src/codegen/llvm/bindings.zig b/src/codegen/llvm/bindings.zig
index 29a46a81ee..dfa7dbc9ec 100644
--- a/src/codegen/llvm/bindings.zig
+++ b/src/codegen/llvm/bindings.zig
@@ -567,6 +567,15 @@ pub const Builder = opaque {
         Name: [*:0]const u8,
     ) *const Value;
 
+    pub const buildInsertElement = LLVMBuildInsertElement;
+    extern fn LLVMBuildInsertElement(
+        *const Builder,
+        VecVal: *const Value,
+        EltVal: *const Value,
+        Index: *const Value,
+        Name: [*:0]const u8,
+    ) *const Value;
+
     pub const buildPtrToInt = LLVMBuildPtrToInt;
     extern fn LLVMBuildPtrToInt(
         *const Builder,

From fd838584bfdc5ef4fb57927bded9e34474bc59d3 Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 16 Oct 2021 19:51:39 +0200
Subject: [PATCH 4/6] stage2: vector constants

---
 src/codegen/llvm.zig          | 61 ++++++++++++++++++++++++++++++++++-
 src/codegen/llvm/bindings.zig |  6 ++++
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 70442729ba..61227b188c 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -1279,6 +1279,66 @@ pub const DeclGen = struct {
                 }
                 return llvm_union_ty.constNamedStruct(&fields, fields.len);
             },
+            .Vector => switch (tv.val.tag()) {
+                .bytes => {
+                    // Note, sentinel is not stored even if the type has a sentinel.
+                    const bytes = tv.val.castTag(.bytes).?.data;
+                    const vector_len = tv.ty.arrayLen();
+                    assert(vector_len == bytes.len or vector_len + 1 == bytes.len);
+
+                    const elem_ty = tv.ty.elemType();
+                    const llvm_elems = try self.gpa.alloc(*const llvm.Value, vector_len);
+                    defer self.gpa.free(llvm_elems);
+                    for (llvm_elems) |*elem, i| {
+                        var byte_payload: Value.Payload.U64 = .{
+                            .base = .{ .tag = .int_u64 },
+                            .data = bytes[i],
+                        };
+
+                        elem.* = try self.genTypedValue(.{
+                            .ty = elem_ty,
+                            .val = Value.initPayload(&byte_payload.base),
+                        });
+                    }
+                    return llvm.constVector(
+                        llvm_elems.ptr,
+                        @intCast(c_uint, llvm_elems.len),
+                    );
+                },
+                .array => {
+                    // Note, sentinel is not stored even if the type has a sentinel.
+                    // The value includes the sentinel in those cases.
+                    const elem_vals = tv.val.castTag(.array).?.data;
+                    const vector_len = tv.ty.arrayLen();
+                    assert(vector_len == elem_vals.len or vector_len + 1 == elem_vals.len);
+                    const elem_ty = tv.ty.elemType();
+                    const llvm_elems = try self.gpa.alloc(*const llvm.Value, vector_len);
+                    defer self.gpa.free(llvm_elems);
+                    for (llvm_elems) |*elem, i| {
+                        elem.* = try self.genTypedValue(.{ .ty = elem_ty, .val = elem_vals[i] });
+                    }
+                    return llvm.constVector(
+                        llvm_elems.ptr,
+                        @intCast(c_uint, llvm_elems.len),
+                    );
+                },
+                .repeated => {
+                    // Note, sentinel is not stored even if the type has a sentinel.
+                    const val = tv.val.castTag(.repeated).?.data;
+                    const elem_ty = tv.ty.elemType();
+                    const len = tv.ty.arrayLen();
+                    const llvm_elems = try self.gpa.alloc(*const llvm.Value, len);
+                    defer self.gpa.free(llvm_elems);
+                    for (llvm_elems) |*elem| {
+                        elem.* = try self.genTypedValue(.{ .ty = elem_ty, .val = val });
+                    }
+                    return llvm.constVector(
+                        llvm_elems.ptr,
+                        @intCast(c_uint, llvm_elems.len),
+                    );
+                },
+                else => unreachable,
+            },
 
             .ComptimeInt => unreachable,
             .ComptimeFloat => unreachable,
@@ -1293,7 +1353,6 @@ pub const DeclGen = struct {
 
             .Frame,
             .AnyFrame,
-            .Vector,
             => return self.todo("implement const of type '{}'", .{tv.ty}),
         }
     }
diff --git a/src/codegen/llvm/bindings.zig b/src/codegen/llvm/bindings.zig
index dfa7dbc9ec..1b7806d22a 100644
--- a/src/codegen/llvm/bindings.zig
+++ b/src/codegen/llvm/bindings.zig
@@ -313,6 +313,12 @@ pub const VerifierFailureAction = enum(c_int) {
 pub const constNeg = LLVMConstNeg;
 extern fn LLVMConstNeg(ConstantVal: *const Value) *const Value;
 
+pub const constVector = LLVMConstVector;
+extern fn LLVMConstVector(
+    ScalarConstantVals: [*]*const Value,
+    Size: c_uint,
+) *const Value;
+
 pub const getEnumAttributeKindForName = LLVMGetEnumAttributeKindForName;
 extern fn LLVMGetEnumAttributeKindForName(Name: [*]const u8, SLen: usize) c_uint;
 

From d004ef2e5d315e102e5be93ba68443ea0877492c Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sat, 16 Oct 2021 19:55:31 +0200
Subject: [PATCH 5/6] stage2: make zirBoolNot return undefined when argument is
 undefined

---
 src/Sema.zig | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/Sema.zig b/src/Sema.zig
index b9c296bd4b..79469e2eec 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -8271,12 +8271,13 @@ fn zirBoolNot(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
 
     const bool_type = Type.initTag(.bool);
     const operand = try sema.coerce(block, bool_type, uncasted_operand, operand_src);
-    if (try sema.resolveDefinedValue(block, operand_src, operand)) |val| {
-        if (val.toBool()) {
-            return Air.Inst.Ref.bool_false;
-        } else {
-            return Air.Inst.Ref.bool_true;
-        }
+    if (try sema.resolveMaybeUndefVal(block, operand_src, operand)) |val| {
+        return if (val.isUndef())
+            sema.addConstUndef(bool_type)
+        else if (val.toBool())
+            Air.Inst.Ref.bool_false
+        else
+            Air.Inst.Ref.bool_true;
     }
     try sema.requireRuntimeBlock(block, src);
     return block.addTyOp(.not, bool_type, operand);

From 15a0b30d8e905a7b46fa97175d9bdba2bd5a8403 Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Sun, 17 Oct 2021 22:46:36 +0200
Subject: [PATCH 6/6] ci: disable macos stage 2 tests

---
 ci/azure/macos_arm64_script | 3 ++-
 ci/azure/macos_script       | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/ci/azure/macos_arm64_script b/ci/azure/macos_arm64_script
index 138e365404..fc9fc2f954 100755
--- a/ci/azure/macos_arm64_script
+++ b/ci/azure/macos_arm64_script
@@ -53,7 +53,8 @@ cmake .. \
   -DCMAKE_BUILD_TYPE=Release \
   -DZIG_TARGET_TRIPLE="$HOST_TARGET" \
   -DZIG_TARGET_MCPU="$HOST_MCPU" \
-  -DZIG_STATIC=ON
+  -DZIG_STATIC=ON \
+  -DZIG_OMIT_STAGE2=ON
 
 unset CC
 unset CXX
diff --git a/ci/azure/macos_script b/ci/azure/macos_script
index ec384768d6..13e064f0e6 100755
--- a/ci/azure/macos_script
+++ b/ci/azure/macos_script
@@ -39,7 +39,8 @@ cmake .. \
   -DCMAKE_BUILD_TYPE=Release \
   -DZIG_TARGET_TRIPLE="$TARGET" \
   -DZIG_TARGET_MCPU="$MCPU" \
-  -DZIG_STATIC=ON
+  -DZIG_STATIC=ON \
+  -DZIG_OMIT_STAGE2=ON
 
 # Now cmake will use zig as the C/C++ compiler. We reset the environment variables
 # so that installation and testing do not get affected by them.