Commit 0ef26d113a

@@ -1221,16 +1221,9 @@ fn shrScalar(
     const pt = sema.pt;
     const zcu = pt.zcu;
 
-    switch (op) {
-        .shr => {
-            if (lhs_val.isUndef(zcu)) return lhs_val;
-            if (rhs_val.isUndef(zcu)) return pt.undefValue(lhs_ty);
-        },
-        .shr_exact => {
-            if (lhs_val.isUndef(zcu)) return sema.failWithUseOfUndef(block, lhs_src, vec_idx);
-            if (rhs_val.isUndef(zcu)) return sema.failWithUseOfUndef(block, rhs_src, vec_idx);
-        },
-    }
+    if (lhs_val.isUndef(zcu)) return sema.failWithUseOfUndef(block, lhs_src, vec_idx);
+    if (rhs_val.isUndef(zcu)) return sema.failWithUseOfUndef(block, rhs_src, vec_idx);
+
     switch (try rhs_val.orderAgainstZeroSema(pt)) {
         .gt => {},
         .eq => return lhs_val,

@@ -13826,11 +13826,9 @@ fn zirShr(
                     else => unreachable,
                 })).toIntern());
             }
-            if (rhs_val.isUndef(zcu)) switch (air_tag) {
-                .shr => return pt.undefRef(lhs_ty),
-                .shr_exact => return sema.failWithUseOfUndef(block, rhs_src, null),
-                else => unreachable,
-            };
+            if (rhs_val.isUndef(zcu)) {
+                return sema.failWithUseOfUndef(block, rhs_src, null);
+            }
             const bits_val = try pt.intValue(.comptime_int, scalar_ty.intInfo(zcu).bits);
             switch (rhs_ty.zigTypeTag(zcu)) {
                 .int, .comptime_int => {
@@ -13849,11 +13847,9 @@ fn zirShr(
                     var elem_idx: usize = 0;
                     while (elem_idx < rhs_ty.vectorLen(zcu)) : (elem_idx += 1) {
                         const rhs_elem = try rhs_val.elemValue(pt, elem_idx);
-                        if (rhs_elem.isUndef(zcu)) switch (air_tag) {
-                            .shr => continue,
-                            .shr_exact => return sema.failWithUseOfUndef(block, rhs_src, elem_idx),
-                            else => unreachable,
-                        };
+                        if (rhs_elem.isUndef(zcu)) {
+                            return sema.failWithUseOfUndef(block, rhs_src, elem_idx);
+                        }
                         switch (try rhs_elem.orderAgainstZeroSema(pt)) {
                             .gt => {
                                 if (try rhs_elem.compareHeteroSema(.gte, bits_val, pt)) {
@@ -13875,11 +13871,7 @@ fn zirShr(
                 return sema.fail(block, src, "LHS of shift must be a fixed-width integer type, or RHS must be comptime-known", .{});
             }
             if (maybe_lhs_val) |lhs_val| {
-                switch (air_tag) {
-                    .shr => if (lhs_val.isUndef(zcu)) return pt.undefRef(lhs_ty),
-                    .shr_exact => try sema.checkAllScalarsDefined(block, lhs_src, lhs_val),
-                    else => unreachable,
-                }
+                try sema.checkAllScalarsDefined(block, lhs_src, lhs_val);
             }
         }
         break :rs rhs_src;

@@ -196,10 +196,3 @@ test "Saturating Shift Left" {
     try expectEqual(170141183460469231731687303715884105727, S.shlSat(@as(i128, 0x2fe6bc5448c55ce18252e2c9d4477750), 0x31));
     try expectEqual(0, S.shlSat(@as(i128, 0), 127));
 }
-
-test "shift by partially undef vector" {
-    comptime {
-        const a: @Vector(1, u8) = .{undefined};
-        _ = a >> @splat(4);
-    }
-}

@@ -0,0 +1,11 @@
+comptime {
+    var a: i64 = undefined;
+    var b: u6 = undefined;
+    _ = &a;
+    _ = &b;
+    _ = @shlExact(a, b);
+}
+
+// error
+//
+// :6:19: error: use of undefined value here causes illegal behavior

@@ -0,0 +1,11 @@
+comptime {
+    var a: i64 = undefined;
+    var b: u6 = undefined;
+    _ = &a;
+    _ = &b;
+    _ = a << b;
+}
+
+// error
+//
+// :6:9: error: use of undefined value here causes illegal behavior

@@ -0,0 +1,11 @@
+comptime {
+    var a: i64 = undefined;
+    var b: u6 = undefined;
+    _ = &a;
+    _ = &b;
+    _ = @shlWithOverflow(a, b);
+}
+
+// error
+//
+// :6:26: error: use of undefined value here causes illegal behavior

@@ -0,0 +1,11 @@
+comptime {
+    var a: i64 = undefined;
+    var b: u6 = undefined;
+    _ = &a;
+    _ = &b;
+    _ = @shrExact(a, b);
+}
+
+// error
+//
+// :6:19: error: use of undefined value here causes illegal behavior

@@ -0,0 +1,11 @@
+comptime {
+    var a: i64 = undefined;
+    var b: u6 = undefined;
+    _ = &a;
+    _ = &b;
+    _ = a >> b;
+}
+
+// error
+//
+// :6:9: error: use of undefined value here causes illegal behavior