LLVM: implement signext/zeroext attributes

lib/compiler_rt/common.zig

@@ -68,7 +68,11 @@ pub fn panic(msg: []const u8, error_return_trace: ?*std.builtin.StackTrace) nore
 /// need for extending them to wider fp types.
 /// TODO remove this; do this type selection in the language rather than
 /// here in compiler-rt.
-pub const F16T = if (builtin.cpu.arch.isAARCH64()) f16 else u16;
+pub const F16T = switch (builtin.cpu.arch) {
+    .aarch64, .aarch64_be, .aarch64_32 => f16,
+    .riscv64 => if (builtin.zig_backend == .stage1) u16 else f16,
+    else => u16,
+};
 
 pub fn wideMultiply(comptime Z: type, a: Z, b: Z, hi: *Z, lo: *Z) void {
     switch (Z) {

lib/std/math/float.zig

@@ -3,20 +3,20 @@ const assert = std.debug.assert;
 const expect = std.testing.expect;
 
 /// Creates a raw "1.0" mantissa for floating point type T. Used to dedupe f80 logic.
-fn mantissaOne(comptime T: type) comptime_int {
+inline fn mantissaOne(comptime T: type) comptime_int {
     return if (@typeInfo(T).Float.bits == 80) 1 << floatFractionalBits(T) else 0;
 }
 
 /// Creates floating point type T from an unbiased exponent and raw mantissa.
-fn reconstructFloat(comptime T: type, exponent: comptime_int, mantissa: comptime_int) T {
-    const TBits = std.meta.Int(.unsigned, @bitSizeOf(T));
+inline fn reconstructFloat(comptime T: type, exponent: comptime_int, mantissa: comptime_int) T {
+    const TBits = @Type(.{ .Int = .{ .signedness = .unsigned, .bits = @bitSizeOf(T) } });
     const biased_exponent = @as(TBits, exponent + floatExponentMax(T));
     return @bitCast(T, (biased_exponent << floatMantissaBits(T)) | @as(TBits, mantissa));
 }
 
 /// Returns the number of bits in the exponent of floating point type T.
-pub fn floatExponentBits(comptime T: type) comptime_int {
-    assert(@typeInfo(T) == .Float);
+pub inline fn floatExponentBits(comptime T: type) comptime_int {
+    comptime assert(@typeInfo(T) == .Float);
 
     return switch (@typeInfo(T).Float.bits) {
         16 => 5,
@@ -29,8 +29,8 @@ pub fn floatExponentBits(comptime T: type) comptime_int {
 }
 
 /// Returns the number of bits in the mantissa of floating point type T.
-pub fn floatMantissaBits(comptime T: type) comptime_int {
-    assert(@typeInfo(T) == .Float);
+pub inline fn floatMantissaBits(comptime T: type) comptime_int {
+    comptime assert(@typeInfo(T) == .Float);
 
     return switch (@typeInfo(T).Float.bits) {
         16 => 10,
@@ -43,8 +43,8 @@ pub fn floatMantissaBits(comptime T: type) comptime_int {
 }
 
 /// Returns the number of fractional bits in the mantissa of floating point type T.
-pub fn floatFractionalBits(comptime T: type) comptime_int {
-    assert(@typeInfo(T) == .Float);
+pub inline fn floatFractionalBits(comptime T: type) comptime_int {
+    comptime assert(@typeInfo(T) == .Float);
 
     // standard IEEE floats have an implicit 0.m or 1.m integer part
     // f80 is special and has an explicitly stored bit in the MSB
@@ -61,43 +61,43 @@ pub fn floatFractionalBits(comptime T: type) comptime_int {
 
 /// Returns the minimum exponent that can represent
 /// a normalised value in floating point type T.
-pub fn floatExponentMin(comptime T: type) comptime_int {
+pub inline fn floatExponentMin(comptime T: type) comptime_int {
     return -floatExponentMax(T) + 1;
 }
 
 /// Returns the maximum exponent that can represent
 /// a normalised value in floating point type T.
-pub fn floatExponentMax(comptime T: type) comptime_int {
+pub inline fn floatExponentMax(comptime T: type) comptime_int {
     return (1 << (floatExponentBits(T) - 1)) - 1;
 }
 
 /// Returns the smallest subnormal number representable in floating point type T.
-pub fn floatTrueMin(comptime T: type) T {
+pub inline fn floatTrueMin(comptime T: type) T {
     return reconstructFloat(T, floatExponentMin(T) - 1, 1);
 }
 
 /// Returns the smallest normal number representable in floating point type T.
-pub fn floatMin(comptime T: type) T {
+pub inline fn floatMin(comptime T: type) T {
     return reconstructFloat(T, floatExponentMin(T), mantissaOne(T));
 }
 
 /// Returns the largest normal number representable in floating point type T.
-pub fn floatMax(comptime T: type) T {
+pub inline fn floatMax(comptime T: type) T {
     const all1s_mantissa = (1 << floatMantissaBits(T)) - 1;
     return reconstructFloat(T, floatExponentMax(T), all1s_mantissa);
 }
 
 /// Returns the machine epsilon of floating point type T.
-pub fn floatEps(comptime T: type) T {
+pub inline fn floatEps(comptime T: type) T {
     return reconstructFloat(T, -floatFractionalBits(T), mantissaOne(T));
 }
 
 /// Returns the value inf for floating point type T.
-pub fn inf(comptime T: type) T {
+pub inline fn inf(comptime T: type) T {
     return reconstructFloat(T, floatExponentMax(T) + 1, mantissaOne(T));
 }
 
-test "std.math.float" {
+test "float bits" {
     inline for ([_]type{ f16, f32, f64, f80, f128, c_longdouble }) |T| {
         // (1 +) for the sign bit, since it is separate from the other bits
         const size = 1 + floatExponentBits(T) + floatMantissaBits(T);

lib/std/math/isinf.zig

@@ -3,20 +3,20 @@ const math = std.math;
 const expect = std.testing.expect;
 
 /// Returns whether x is an infinity, ignoring sign.
-pub fn isInf(x: anytype) bool {
+pub inline fn isInf(x: anytype) bool {
     const T = @TypeOf(x);
     const TBits = std.meta.Int(.unsigned, @typeInfo(T).Float.bits);
     const remove_sign = ~@as(TBits, 0) >> 1;
     return @bitCast(TBits, x) & remove_sign == @bitCast(TBits, math.inf(T));
 }
 
 /// Returns whether x is an infinity with a positive sign.
-pub fn isPositiveInf(x: anytype) bool {
+pub inline fn isPositiveInf(x: anytype) bool {
     return x == math.inf(@TypeOf(x));
 }
 
 /// Returns whether x is an infinity with a negative sign.
-pub fn isNegativeInf(x: anytype) bool {
+pub inline fn isNegativeInf(x: anytype) bool {
     return x == -math.inf(@TypeOf(x));
 }
 

src/Sema.zig

@@ -22571,6 +22571,48 @@ fn bitCastVal(
     const target = sema.mod.getTarget();
     if (old_ty.eql(new_ty, sema.mod)) return val;
 
+    // Some conversions have a bitwise definition that ignores in-memory layout,
+    // such as converting between f80 and u80.
+
+    if (old_ty.eql(Type.f80, sema.mod) and new_ty.isAbiInt()) {
+        const float = val.toFloat(f80);
+        switch (new_ty.intInfo(target).signedness) {
+            .signed => {
+                const int = @bitCast(i80, float);
+                const limbs = try sema.arena.alloc(std.math.big.Limb, 2);
+                const big_int = std.math.big.int.Mutable.init(limbs, int);
+                return Value.fromBigInt(sema.arena, big_int.toConst());
+            },
+            .unsigned => {
+                const int = @bitCast(u80, float);
+                const limbs = try sema.arena.alloc(std.math.big.Limb, 2);
+                const big_int = std.math.big.int.Mutable.init(limbs, int);
+                return Value.fromBigInt(sema.arena, big_int.toConst());
+            },
+        }
+    }
+
+    if (new_ty.eql(Type.f80, sema.mod) and old_ty.isAbiInt()) {
+        var bigint_space: Value.BigIntSpace = undefined;
+        var bigint = try val.toBigIntAdvanced(&bigint_space, target, sema.kit(block, src));
+        switch (old_ty.intInfo(target).signedness) {
+            .signed => {
+                // This conversion cannot fail because we already checked bit size before
+                // calling bitCastVal.
+                const int = bigint.to(i80) catch unreachable;
+                const float = @bitCast(f80, int);
+                return Value.Tag.float_80.create(sema.arena, float);
+            },
+            .unsigned => {
+                // This conversion cannot fail because we already checked bit size before
+                // calling bitCastVal.
+                const int = bigint.to(u80) catch unreachable;
+                const float = @bitCast(f80, int);
+                return Value.Tag.float_80.create(sema.arena, float);
+            },
+        }
+    }
+
     // For types with well-defined memory layouts, we serialize them a byte buffer,
     // then deserialize to the new type.
     const abi_size = try sema.usizeCast(block, src, old_ty.abiSize(target));

src/codegen/llvm.zig

@@ -717,6 +717,11 @@ pub const Object = struct {
         const ret_ptr = if (sret) llvm_func.getParam(0) else null;
         const gpa = dg.gpa;
 
+        if (ccAbiPromoteInt(fn_info.cc, target, fn_info.return_type)) |s| switch (s) {
+            .signed => dg.addAttr(llvm_func, 0, "signext"),
+            .unsigned => dg.addAttr(llvm_func, 0, "zeroext"),
+        };
+
         const err_return_tracing = fn_info.return_type.isError() and
             dg.module.comp.bin_file.options.error_return_tracing;
 
@@ -774,7 +779,10 @@ pub const Object = struct {
                                 );
                                 dg.addArgAttrInt(llvm_func, llvm_arg_i, "align", elem_align);
                             }
-                        }
+                        } else if (ccAbiPromoteInt(fn_info.cc, target, param_ty)) |s| switch (s) {
+                            .signed => dg.addArgAttr(llvm_func, llvm_arg_i, "signext"),
+                            .unsigned => dg.addArgAttr(llvm_func, llvm_arg_i, "zeroext"),
+                        };
                     }
                     llvm_arg_i += 1;
                 },
@@ -887,6 +895,13 @@ pub const Object = struct {
                     };
                     try args.append(loaded);
                 },
+                .as_u16 => {
+                    const param = llvm_func.getParam(llvm_arg_i);
+                    llvm_arg_i += 1;
+                    const casted = builder.buildBitCast(param, dg.context.halfType(), "");
+                    try args.ensureUnusedCapacity(1);
+                    args.appendAssumeCapacity(casted);
+                },
             };
         }
 
@@ -2794,6 +2809,9 @@ pub const DeclGen = struct {
                     llvm_params.appendAssumeCapacity(big_int_ty);
                 }
             },
+            .as_u16 => {
+                try llvm_params.append(dg.context.intType(16));
+            },
         };
 
         return llvm.functionType(
@@ -4234,6 +4252,12 @@ pub const FuncGen = struct {
                     llvm_args.appendAssumeCapacity(load_inst);
                 }
             },
+            .as_u16 => {
+                const arg = args[it.zig_index - 1];
+                const llvm_arg = try self.resolveInst(arg);
+                const casted = self.builder.buildBitCast(llvm_arg, self.dg.context.intType(16), "");
+                try llvm_args.append(casted);
+            },
         };
 
         const call = self.builder.buildCall(
@@ -8965,6 +8989,7 @@ const ParamTypeIterator = struct {
         abi_sized_int,
         multiple_llvm_ints,
         slice,
+        as_u16,
     };
 
     pub fn next(it: *ParamTypeIterator) ?Lowering {
@@ -9025,6 +9050,15 @@ const ParamTypeIterator = struct {
                     else => false,
                 };
                 switch (it.target.cpu.arch) {
+                    .riscv32, .riscv64 => {
+                        it.zig_index += 1;
+                        it.llvm_index += 1;
+                        if (ty.tag() == .f16) {
+                            return .as_u16;
+                        } else {
+                            return .byval;
+                        }
+                    },
                     .mips, .mipsel => {
                         it.zig_index += 1;
                         it.llvm_index += 1;
@@ -9135,6 +9169,35 @@ fn iterateParamTypes(dg: *DeclGen, fn_info: Type.Payload.Function.Data) ParamTyp
     };
 }
 
+fn ccAbiPromoteInt(
+    cc: std.builtin.CallingConvention,
+    target: std.Target,
+    ty: Type,
+) ?std.builtin.Signedness {
+    switch (cc) {
+        .Unspecified, .Inline, .Async => return null,
+        else => {},
+    }
+    const int_info = switch (ty.zigTypeTag()) {
+        .Int, .Enum, .ErrorSet => ty.intInfo(target),
+        else => return null,
+    };
+    if (int_info.bits <= 16) return int_info.signedness;
+    switch (target.cpu.arch) {
+        .sparc64,
+        .riscv64,
+        .powerpc64,
+        .powerpc64le,
+        => {
+            if (int_info.bits < 64) {
+                return int_info.signedness;
+            }
+        },
+        else => {},
+    }
+    return null;
+}
+
 fn isByRef(ty: Type) bool {
     // For tuples and structs, if there are more than this many non-void
     // fields, then we make it byref, otherwise byval.

src/type.zig

@@ -4439,6 +4439,16 @@ pub const Type = extern union {
         };
     }
 
+    /// Returns true for integers, enums, error sets, and packed structs.
+    /// If this function returns true, then intInfo() can be called on the type.
+    pub fn isAbiInt(ty: Type) bool {
+        return switch (ty.zigTypeTag()) {
+            .Int, .Enum, .ErrorSet => true,
+            .Struct => ty.containerLayout() == .Packed,
+            else => false,
+        };
+    }
+
     /// Asserts the type is an integer, enum, error set, or vector of one of them.
     pub fn intInfo(self: Type, target: Target) struct { signedness: std.builtin.Signedness, bits: u16 } {
         var ty = self;

src/value.zig

@@ -1468,8 +1468,7 @@ pub const Value = extern union {
             const repr = std.math.break_f80(f);
             std.mem.writeInt(u64, buffer[0..8], repr.fraction, endian);
             std.mem.writeInt(u16, buffer[8..10], repr.exp, endian);
-            // TODO set the rest of the bytes to undefined. should we use 0xaa
-            // or is there a different way?
+            std.mem.set(u8, buffer[10..], 0);
             return;
         }
         const Int = @Type(.{ .Int = .{
@@ -1481,20 +1480,18 @@ pub const Value = extern union {
     }
 
     fn floatReadFromMemory(comptime F: type, target: Target, buffer: []const u8) F {
+        const endian = target.cpu.arch.endian();
         if (F == f80) {
-            switch (target.cpu.arch) {
-                .i386, .x86_64 => return std.math.make_f80(.{
-                    .fraction = std.mem.readIntLittle(u64, buffer[0..8]),
-                    .exp = std.mem.readIntLittle(u16, buffer[8..10]),
-                }),
-                else => {},
-            }
+            return std.math.make_f80(.{
+                .fraction = readInt(u64, buffer[0..8], endian),
+                .exp = readInt(u16, buffer[8..10], endian),
+            });
         }
         const Int = @Type(.{ .Int = .{
             .signedness = .unsigned,
             .bits = @typeInfo(F).Float.bits,
         } });
-        const int = readInt(Int, buffer[0..@sizeOf(Int)], target.cpu.arch.endian());
+        const int = readInt(Int, buffer[0..@sizeOf(Int)], endian);
         return @bitCast(F, int);
     }