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stage2: Implement @bitReverse and @byteSwap

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This change implements the above built-ins for Sema and the LLVM
backend. Other backends have had placeholders added for lowering.
This commit is contained in:
Cody Tapscott
2022-02-13 15:04:46 -07:00
parent dee96e2e2f
commit ef417f19e1
17 changed files with 487 additions and 21 deletions
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2
src/codegen/c.zig
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@@ -1709,6 +1709,8 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO
.clz => try airBuiltinCall(f, inst, "clz"),
.ctz => try airBuiltinCall(f, inst, "ctz"),
.popcount => try airBuiltinCall(f, inst, "popcount"),
.byte_swap => try airBuiltinCall(f, inst, "byte_swap"),
.bit_reverse => try airBuiltinCall(f, inst, "bit_reverse"),
.tag_name => try airTagName(f, inst),
.error_name => try airErrorName(f, inst),
.splat => try airSplat(f, inst),

46
src/codegen/llvm.zig
View File

@@ -2205,7 +2205,9 @@ pub const FuncGen = struct {
.get_union_tag => try self.airGetUnionTag(inst),
.clz => try self.airClzCtz(inst, "llvm.ctlz"),
.ctz => try self.airClzCtz(inst, "llvm.cttz"),
.popcount => try self.airPopCount(inst),
.popcount => try self.airBitOp(inst, "llvm.ctpop"),
.byte_swap => try self.airByteSwap(inst, "llvm.bswap"),
.bit_reverse => try self.airBitOp(inst, "llvm.bitreverse"),
.tag_name => try self.airTagName(inst),
.error_name => try self.airErrorName(inst),
.splat => try self.airSplat(inst),
@@ -4348,7 +4350,7 @@ pub const FuncGen = struct {
}
}
fn airPopCount(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
fn airBitOp(self: *FuncGen, inst: Air.Inst.Index, llvm_fn_name: []const u8) !?*const llvm.Value {
if (self.liveness.isUnused(inst)) return null;
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
@@ -4357,7 +4359,7 @@ pub const FuncGen = struct {
const params = [_]*const llvm.Value{operand};
const operand_llvm_ty = try self.dg.llvmType(operand_ty);
const fn_val = self.getIntrinsic("llvm.ctpop", &.{operand_llvm_ty});
const fn_val = self.getIntrinsic(llvm_fn_name, &.{operand_llvm_ty});
const wrong_size_result = self.builder.buildCall(fn_val, &params, params.len, .C, .Auto, "");
const result_ty = self.air.typeOfIndex(inst);
@@ -4375,6 +4377,44 @@ pub const FuncGen = struct {
}
}
fn airByteSwap(self: *FuncGen, inst: Air.Inst.Index, llvm_fn_name: []const u8) !?*const llvm.Value {
if (self.liveness.isUnused(inst)) return null;
const target = self.dg.module.getTarget();
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand_ty = self.air.typeOf(ty_op.operand);
var bits = operand_ty.intInfo(target).bits;
assert(bits % 8 == 0);
var operand = try self.resolveInst(ty_op.operand);
var operand_llvm_ty = try self.dg.llvmType(operand_ty);
if (bits % 16 == 8) {
// If not an even byte-multiple, we need zero-extend + shift-left 1 byte
// The truncated result at the end will be the correct bswap
operand_llvm_ty = self.context.intType(bits + 8);
const extended = self.builder.buildZExt(operand, operand_llvm_ty, "");
operand = self.builder.buildShl(extended, operand_llvm_ty.constInt(8, .False), "");
bits = bits + 8;
}
const params = [_]*const llvm.Value{operand};
const fn_val = self.getIntrinsic(llvm_fn_name, &.{operand_llvm_ty});
const wrong_size_result = self.builder.buildCall(fn_val, &params, params.len, .C, .Auto, "");
const result_ty = self.air.typeOfIndex(inst);
const result_llvm_ty = try self.dg.llvmType(result_ty);
const result_bits = result_ty.intInfo(target).bits;
if (bits > result_bits) {
return self.builder.buildTrunc(wrong_size_result, result_llvm_ty, "");
} else if (bits < result_bits) {
return self.builder.buildZExt(wrong_size_result, result_llvm_ty, "");
} else {
return wrong_size_result;
}
}
fn airTagName(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
if (self.liveness.isUnused(inst)) return null;