diff options
Diffstat (limited to 'src/codegen.cpp')
| -rw-r--r-- | src/codegen.cpp | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/src/codegen.cpp b/src/codegen.cpp index cf8af9664f..3b3a97dbfa 100644 --- a/src/codegen.cpp +++ b/src/codegen.cpp @@ -2455,8 +2455,8 @@ static LLVMValueRef gen_div(CodeGen *g, bool want_runtime_safety, bool want_fast } else { zig_unreachable(); } - LLVMBasicBlockRef div_zero_ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivZeroOk"); LLVMBasicBlockRef div_zero_fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivZeroFail"); + LLVMBasicBlockRef div_zero_ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivZeroOk"); LLVMBuildCondBr(g->builder, is_zero_bit, div_zero_fail_block, div_zero_ok_block); LLVMPositionBuilderAtEnd(g->builder, div_zero_fail_block); @@ -2469,8 +2469,8 @@ static LLVMValueRef gen_div(CodeGen *g, bool want_runtime_safety, bool want_fast BigInt int_min_bi = {0}; eval_min_max_value_int(g, type_entry, &int_min_bi, false); LLVMValueRef int_min_value = bigint_to_llvm_const(get_llvm_type(g, type_entry), &int_min_bi); - LLVMBasicBlockRef overflow_ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivOverflowOk"); LLVMBasicBlockRef overflow_fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivOverflowFail"); + LLVMBasicBlockRef overflow_ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "DivOverflowOk"); LLVMValueRef num_is_int_min = LLVMBuildICmp(g->builder, LLVMIntEQ, val1, int_min_value, ""); LLVMValueRef den_is_neg_1 = LLVMBuildICmp(g->builder, LLVMIntEQ, val2, neg_1_value, ""); LLVMValueRef overflow_fail_bit = LLVMBuildAnd(g->builder, num_is_int_min, den_is_neg_1, ""); @@ -2574,20 +2574,19 @@ static LLVMValueRef gen_div(CodeGen *g, bool want_runtime_safety, bool want_fast if (!type_entry->data.integral.is_signed) { return LLVMBuildUDiv(g->builder, val1, val2, ""); } - // const result = @divTrunc(a, b); - // if (result >= 0 or result * b == a) - // return result; - // else - // return result - 1; - - LLVMValueRef result = LLVMBuildSDiv(g->builder, val1, val2, ""); - LLVMValueRef is_pos = LLVMBuildICmp(g->builder, LLVMIntSGE, result, zero, ""); - LLVMValueRef orig_num = LLVMBuildNSWMul(g->builder, result, val2, ""); - LLVMValueRef orig_ok = LLVMBuildICmp(g->builder, LLVMIntEQ, orig_num, val1, ""); - LLVMValueRef ok_bit = LLVMBuildOr(g->builder, orig_ok, is_pos, ""); - LLVMValueRef one = LLVMConstInt(get_llvm_type(g, type_entry), 1, true); - LLVMValueRef result_minus_1 = LLVMBuildNSWSub(g->builder, result, one, ""); - return LLVMBuildSelect(g->builder, ok_bit, result, result_minus_1, ""); + // const d = @divTrunc(a, b); + // const r = @rem(a, b); + // return if (r == 0) d else d - ((a < 0) ^ (b < 0)); + + LLVMValueRef div_trunc = LLVMBuildSDiv(g->builder, val1, val2, ""); + LLVMValueRef rem = LLVMBuildSRem(g->builder, val1, val2, ""); + LLVMValueRef rem_eq_0 = LLVMBuildICmp(g->builder, LLVMIntEQ, rem, zero, ""); + LLVMValueRef a_lt_0 = LLVMBuildICmp(g->builder, LLVMIntSLT, val1, zero, ""); + LLVMValueRef b_lt_0 = LLVMBuildICmp(g->builder, LLVMIntSLT, val2, zero, ""); + LLVMValueRef a_b_xor = LLVMBuildXor(g->builder, a_lt_0, b_lt_0, ""); + LLVMValueRef a_b_xor_ext = LLVMBuildZExt(g->builder, a_b_xor, LLVMTypeOf(div_trunc), ""); + LLVMValueRef d_sub_xor = LLVMBuildSub(g->builder, div_trunc, a_b_xor_ext, ""); + return LLVMBuildSelect(g->builder, rem_eq_0, div_trunc, d_sub_xor, ""); } } zig_unreachable(); |