Sema: return comptime_int if all args to @min/@max are comptime_int

Resolves: #15776
ziglang · May 29, 2023 · e2837fd · e2837fd
1 parent 46e724a
commit e2837fd
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Showing 2 changed files with 26 additions and 1 deletion.
diff --git a/src/Sema.zig b/src/Sema.zig
@@ -21940,10 +21940,18 @@ fn analyzeMinMax(
  }
  }
 
+ const opt_runtime_idx = runtime_known.findFirstSet();
+
  const comptime_refined_ty: ?Type = if (cur_minmax) |ct_minmax_ref| refined: {
  // Refine the comptime-known result type based on the operation
  const val = (try sema.resolveMaybeUndefVal(ct_minmax_ref)).?;
  const orig_ty = sema.typeOf(ct_minmax_ref);
+
+ if (opt_runtime_idx == null and orig_ty.eql(Type.comptime_int, mod)) {
+ // If all arguments were `comptime_int`, and there are no runtime args, we'll preserve that type
+ break :refined orig_ty;
+ }
+
  const refined_ty = if (orig_ty.zigTypeTag() == .Vector) blk: {
  const elem_ty = orig_ty.childType();
  const len = orig_ty.vectorLen();
@@ -21982,7 +21990,7 @@ fn analyzeMinMax(
  break :refined refined_ty;
  } else null;
 
- const runtime_idx = runtime_known.findFirstSet() orelse return cur_minmax.?;
+ const runtime_idx = opt_runtime_idx orelse return cur_minmax.?;
  const runtime_src = operand_srcs[runtime_idx];
  try sema.requireRuntimeBlock(block, src, runtime_src);
 

diff --git a/test/behavior/maximum_minimum.zig b/test/behavior/maximum_minimum.zig
@@ -194,3 +194,20 @@ test "@min/@max notices vector bounds" {
  try expectEqual(@Vector(2, u32){ 140, 300 }, max);
  try expectEqual(@Vector(2, u32), @TypeOf(max));
 }
+
+test "@min/@max on comptime_int" {
+ if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+ if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+ if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+ if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+ if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+ if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+ const min = @min(1, 2, -2, -1);
+ const max = @max(1, 2, -2, -1);
+
+ try expectEqual(comptime_int, @TypeOf(min));
+ try expectEqual(comptime_int, @TypeOf(max));
+ try expectEqual(-2, min);
+ try expectEqual(2, max);
+}