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stage2: implement some casts for numbers

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This commit is contained in:
Vexu
2020-07-20 22:45:27 +03:00
parent da217fadeb
commit 7b52dbbf83
4 changed files with 74 additions and 15 deletions
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62
src-self-hosted/Module.zig
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@@ -3358,6 +3358,14 @@ fn coerce(self: *Module, scope: *Scope, dest_type: Type, inst: *Inst) !*Inst {
return self.bitcast(scope, dest_type, inst);
}
// undefined to anything
if (inst.value()) |val| {
if (val.isUndef() or inst.ty.zigTypeTag() == .Undefined) {
return self.constInst(scope, inst.src, .{ .ty = dest_type, .val = val });
}
}
assert(inst.ty.zigTypeTag() != .Undefined);
// *[N]T to []T
if (inst.ty.isSinglePointer() and dest_type.isSlice() and
(!inst.ty.pointerIsConst() or dest_type.pointerIsConst()))
@@ -3371,34 +3379,58 @@ fn coerce(self: *Module, scope: *Scope, dest_type: Type, inst: *Inst) !*Inst {
}
}
// comptime_int to fixed-width integer
if (inst.ty.zigTypeTag() == .ComptimeInt and dest_type.zigTypeTag() == .Int) {
// The representation is already correct; we only need to make sure it fits in the destination type.
const val = inst.value().?; // comptime_int always has comptime known value
if (!val.intFitsInType(dest_type, self.target())) {
return self.fail(scope, inst.src, "type {} cannot represent integer value {}", .{ inst.ty, val });
// comptime known number to other number
if (inst.value()) |val| {
const src_zig_tag = inst.ty.zigTypeTag();
const dst_zig_tag = dest_type.zigTypeTag();
if (dst_zig_tag == .ComptimeInt or dst_zig_tag == .Int) {
if (src_zig_tag == .Float or src_zig_tag == .ComptimeFloat) {
if (val.floatHasFraction()) {
return self.fail(scope, inst.src, "fractional component prevents float value {} from being casted to type '{}'", .{ val, inst.ty });
}
return self.fail(scope, inst.src, "TODO float to int", .{});
} else if (src_zig_tag == .Int or src_zig_tag == .ComptimeInt) {
if (!val.intFitsInType(dest_type, self.target())) {
return self.fail(scope, inst.src, "type {} cannot represent integer value {}", .{ inst.ty, val });
}
return self.constInst(scope, inst.src, .{ .ty = dest_type, .val = val });
}
} else if (dst_zig_tag == .ComptimeFloat or dst_zig_tag == .Float) {
if (src_zig_tag == .Float or src_zig_tag == .ComptimeFloat) {
return self.fail(scope, inst.src, "TODO float cast", .{});
} else if (src_zig_tag == .Int or src_zig_tag == .ComptimeInt) {
return self.fail(scope, inst.src, "TODO int to float", .{});
}
}
return self.constInst(scope, inst.src, .{ .ty = dest_type, .val = val });
}
// integer widening
if (inst.ty.zigTypeTag() == .Int and dest_type.zigTypeTag() == .Int) {
assert(inst.value() == null); // handled above
const src_info = inst.ty.intInfo(self.target());
const dst_info = dest_type.intInfo(self.target());
if (src_info.signed == dst_info.signed and dst_info.bits >= src_info.bits) {
if (inst.value()) |val| {
return self.constInst(scope, inst.src, .{ .ty = dest_type, .val = val });
} else {
return self.fail(scope, inst.src, "TODO implement runtime integer widening ({} to {})", .{
inst.ty,
dest_type,
});
}
const b = try self.requireRuntimeBlock(scope, inst.src);
return self.addNewInstArgs(b, inst.src, dest_type, Inst.WidenOrShorten, .{ .operand = inst });
} else {
return self.fail(scope, inst.src, "TODO implement more int widening {} to {}", .{ inst.ty, dest_type });
}
}
// float widening
if (inst.ty.zigTypeTag() == .Float and dest_type.zigTypeTag() == .Float) {
assert(inst.value() == null); // handled above
const src_bits = inst.ty.floatBits(self.target());
const dst_bits = dest_type.floatBits(self.target());
if (dst_bits >= src_bits) {
const b = try self.requireRuntimeBlock(scope, inst.src);
return self.addNewInstArgs(b, inst.src, dest_type, Inst.WidenOrShorten, .{ .operand = inst });
}
}
return self.fail(scope, inst.src, "TODO implement type coercion from {} to {}", .{ inst.ty, dest_type });
}