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fix @divFloor returning incorrect value and add __modti3

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Closes #2152
See #1290
This commit is contained in:
Andrew Kelley
2019-04-04 15:44:19 -04:00
parent 12c4ab3927
commit be0f656c21
7 changed files with 102 additions and 16 deletions
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29
src/codegen.cpp
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@@ -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;
// const d = @divTrunc(a, b);
// const r = @rem(a, b);
// return if (r == 0) d else d - ((a < 0) ^ (b < 0));
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, "");
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();