Commit ba31a9469f48065c9ebf935160faffd0f6c9bfdc | zig

author	Andrew Kelley <andrew@ziglang.org> 2022-02-10 23:56:09-07:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2022-02-12 11:18:23+01:00
log	ba31a9469f48065c9ebf935160faffd0f6c9bfdc
tree	4954ac369623951c5390ab9e2da0e089592f8a4c
parent	b92e1ab8ccf4e450467dfd5ee8ff9ea87c148c26

Sema: int casting to u0 returns const value

Also shift left with u0 rhs returns lhs even when lhs is runtime known.

1 files changed, 16 insertions(+), 12 deletions(-)

src
- Sema.zig

src/Sema.zig+16-12

 @@ -5977,8 +5977,13 @@ fn zirIntCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
         return sema.fail(block, src, "unable to cast runtime value to 'comptime_int'", .{});
     }
-    try sema.requireRuntimeBlock(block, operand_src);
     // TODO insert safety check to make sure the value fits in the dest type
+    if ((try sema.typeHasOnePossibleValue(block, dest_ty_src, dest_ty))) |opv| {
+        return sema.addConstant(dest_ty, opv);
+    }
+    try sema.requireRuntimeBlock(block, operand_src);
     return block.addTyOp(.intcast, dest_ty, operand);
 }
 @@ -7537,17 +7542,21 @@ fn zirShl(
     const maybe_lhs_val = try sema.resolveMaybeUndefVal(block, lhs_src, lhs);
     const maybe_rhs_val = try sema.resolveMaybeUndefVal(block, rhs_src, rhs);
+    if (maybe_rhs_val) |rhs_val| {
+        if (rhs_val.isUndef()) {
+            return sema.addConstUndef(sema.typeOf(lhs));
+        }
+        if (rhs_val.compareWithZero(.eq)) {
+            return lhs;
+        }
+    }
     const runtime_src = if (maybe_lhs_val) |lhs_val| rs: {
         const lhs_ty = sema.typeOf(lhs);
         if (lhs_val.isUndef()) return sema.addConstUndef(lhs_ty);
         const rhs_val = maybe_rhs_val orelse break :rs rhs_src;
-        if (rhs_val.isUndef()) return sema.addConstUndef(lhs_ty);
-        // If rhs is 0, return lhs without doing any calculations.
-        if (rhs_val.compareWithZero(.eq)) {
-            return sema.addConstant(lhs_ty, lhs_val);
-        }
         const target = sema.mod.getTarget();
         const val = switch (air_tag) {
             .shl_exact => val: {
 @@ -7577,12 +7586,7 @@ fn zirShl(
         };
         return sema.addConstant(lhs_ty, val);
-    } else rs: {
+    } else lhs_src;
-        if (maybe_rhs_val) |rhs_val| {
-            if (rhs_val.isUndef()) return sema.addConstUndef(sema.typeOf(lhs));
-        }
-        break :rs lhs_src;
-    };
     // TODO: insert runtime safety check for shl_exact