Commit 70d8baaec11ca370b73fce72d7f3dfce2277455b | zig

author	Andrew Kelley <andrew@ziglang.org> 2023-11-12 14:33:17-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-11-12 14:33:17-07:00
log	70d8baaec11ca370b73fce72d7f3dfce2277455b
tree	96cd79022024f6a65584dd0aab52957d5fb850be
parent	7048e93665543005ed3dabd2e7637f01c584006a

Revert "Sema: fix comparison with undefined"

This reverts commit 547481c31c8a538a7badbdce66d81820177ce87f.

There is a comment that did not get addressed with this patch, and the
required test cases are not added.

Reopens #17798.

2 files changed, 10 insertions(+), 34 deletions(-)

src
- Sema.zig
test
- cases
  - compile_errors
    comparison_with_comptime-known_undefined.zig

src/Sema.zig+10-24

 @@ -8898,16 +8898,10 @@ fn analyzeErrUnionCode(sema: *Sema, block: *Block, src: LazySrcLoc, operand: Air
     const result_ty = operand_ty.errorUnionSet(mod);
     if (try sema.resolveDefinedValue(block, src, operand)) |val| {
-        switch (mod.intern_pool.indexToKey(val.toIntern()).error_union.val) {
+        return Air.internedToRef((try mod.intern(.{ .err = .{
-            .err_name => |err_name| return Air.internedToRef((try mod.intern(.{ .err = .{
+            .ty = result_ty.toIntern(),
-                .ty = result_ty.toIntern(),
+            .name = mod.intern_pool.indexToKey(val.toIntern()).error_union.val.err_name,
-                .name = err_name,
+        } })));
-            } }))),
-            .payload => |payload| {
-                assert(payload.toValue().isUndef(mod));
-                return mod.undefRef(result_ty);
-            },
-        }
     }
     try sema.requireRuntimeBlock(block, src, null);
 @@ -16419,7 +16413,6 @@ fn zirCmp(
     const rhs_src: LazySrcLoc = .{ .node_offset_bin_rhs = inst_data.src_node };
     const lhs = try sema.resolveInst(extra.lhs);
     const rhs = try sema.resolveInst(extra.rhs);
     return sema.analyzeCmp(block, src, lhs, rhs, op, lhs_src, rhs_src, false);
 }
 @@ -16451,16 +16444,10 @@ fn analyzeCmp(
         return sema.cmpNumeric(block, src, lhs, rhs, op, lhs_src, rhs_src);
     }
     if (is_equality_cmp and lhs_ty.zigTypeTag(mod) == .ErrorUnion and rhs_ty.zigTypeTag(mod) == .ErrorSet) {
-        if (try sema.resolveValue(lhs)) |lhs_val| {
-            if (lhs_val.isUndef(mod)) return mod.undefRef(Type.bool);
-        }
         const casted_lhs = try sema.analyzeErrUnionCode(block, lhs_src, lhs);
         return sema.cmpSelf(block, src, casted_lhs, rhs, op, lhs_src, rhs_src);
     }
     if (is_equality_cmp and lhs_ty.zigTypeTag(mod) == .ErrorSet and rhs_ty.zigTypeTag(mod) == .ErrorUnion) {
-        if (try sema.resolveValue(rhs)) |rhs_val| {
-            if (rhs_val.isUndef(mod)) return mod.undefRef(Type.bool);
-        }
         const casted_rhs = try sema.analyzeErrUnionCode(block, rhs_src, rhs);
         return sema.cmpSelf(block, src, lhs, casted_rhs, op, lhs_src, rhs_src);
     }
 @@ -16524,9 +16511,11 @@ fn cmpSelf(
         } else {
             // For bools, we still check the other operand, because we can lower
             // bool eq/neq more efficiently.
-            if (try sema.resolveValue(casted_rhs)) |rhs_val| {
+            if (resolved_type.zigTypeTag(mod) == .Bool) {
-                if (rhs_val.isUndef(mod)) return mod.undefRef(Type.bool);
+                if (try sema.resolveValue(casted_rhs)) |rhs_val| {
-                if (resolved_type.zigTypeTag(mod) == .Bool) return sema.runtimeBoolCmp(block, src, op, casted_lhs, rhs_val.toBool(), lhs_src);
+                    if (rhs_val.isUndef(mod)) return mod.undefRef(Type.bool);
+                    return sema.runtimeBoolCmp(block, src, op, casted_lhs, rhs_val.toBool(), lhs_src);
+                }
             }
             break :src lhs_src;
         }
 @@ -38011,10 +38000,7 @@ fn compareVector(
         const lhs_elem = try lhs.elemValue(sema.mod, i);
         const rhs_elem = try rhs.elemValue(sema.mod, i);
         const res_bool = try sema.compareScalar(lhs_elem, op, rhs_elem, ty.scalarType(mod));
-        scalar.* = if (lhs_elem.isUndef(mod) or rhs_elem.isUndef(mod))
+        scalar.* = try Value.makeBool(res_bool).intern(Type.bool, mod);
-            Air.refToInterned(try mod.undefRef(Type.bool)).?
-        else
-            try Value.makeBool(res_bool).intern(Type.bool, mod);
     }
     return (try mod.intern(.{ .aggregate = .{
         .ty = (try mod.vectorType(.{ .len = ty.vectorLen(mod), .child = .bool_type })).toIntern(),

test/cases/compile_errors/comparison_with_comptime-known_undefined.zig deleted-10

...	@@ -1,10 +0,0 @@
1	pub fn entry() void {
2	var foo: ?*i32 = undefined;
3	if (foo == undefined) {}
4	}
5
6	// error
7	// backend=stage2
8	// target=native
9	//
10	// :3:13: error: use of undefined value here causes undefined behavior