parsec: cleaner shifting code for fixed size types
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@ -163,10 +163,6 @@ static TypeTableEntry *new_container_type_entry(TypeTableEntryId id, AstNode *so
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return entry;
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}
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static uint8_t log2_u64(uint64_t x) {
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return (63 - clzll(x));
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}
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static uint8_t bits_needed_for_unsigned(uint64_t x) {
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if (x == 0) {
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return 0;
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@ -347,9 +347,60 @@ static AstNode* trans_c_cast(Context *c, const SourceLocation &source_location,
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return trans_create_node_fn_call_1(c, trans_qual_type(c, qt, source_location), expr);
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}
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static uint32_t qual_type_int_bit_width(Context *c, const QualType &qt, const SourceLocation &source_loc) {
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const Type *ty = qt.getTypePtr();
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switch (ty->getTypeClass()) {
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case Type::Builtin:
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{
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const BuiltinType *builtin_ty = static_cast<const BuiltinType*>(ty);
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switch (builtin_ty->getKind()) {
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case BuiltinType::Char_U:
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case BuiltinType::UChar:
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case BuiltinType::Char_S:
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case BuiltinType::SChar:
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return 8;
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case BuiltinType::UInt128:
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case BuiltinType::Int128:
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return 128;
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default:
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return 0;
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}
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zig_unreachable();
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}
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case Type::Typedef:
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{
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const TypedefType *typedef_ty = static_cast<const TypedefType*>(ty);
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const TypedefNameDecl *typedef_decl = typedef_ty->getDecl();
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const char *type_name = decl_name(typedef_decl);
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if (strcmp(type_name, "uint8_t") == 0 || strcmp(type_name, "int8_t") == 0) {
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return 8;
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} else if (strcmp(type_name, "uint16_t") == 0 || strcmp(type_name, "int16_t") == 0) {
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return 16;
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} else if (strcmp(type_name, "uint32_t") == 0 || strcmp(type_name, "int32_t") == 0) {
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return 32;
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} else if (strcmp(type_name, "uint64_t") == 0 || strcmp(type_name, "int64_t") == 0) {
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return 64;
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} else {
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return 0;
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}
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}
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default:
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return 0;
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}
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zig_unreachable();
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}
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static AstNode *qual_type_to_log2_int_ref(Context *c, const QualType &qt,
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const SourceLocation &source_loc)
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{
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uint32_t int_bit_width = qual_type_int_bit_width(c, qt, source_loc);
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if (int_bit_width != 0) {
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// we can perform the log2 now.
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uint64_t cast_bit_width = log2_u64(int_bit_width);
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return trans_create_node_symbol(c, buf_sprintf("u%" ZIG_PRI_u64, cast_bit_width));
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}
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AstNode *zig_type_node = trans_qual_type(c, qt, source_loc);
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// @import("std").math.Log2Int(c_long);
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@ -147,4 +147,8 @@ bool uint64_eq(uint64_t a, uint64_t b);
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uint32_t ptr_hash(const void *ptr);
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bool ptr_eq(const void *a, const void *b);
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static inline uint8_t log2_u64(uint64_t x) {
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return (63 - clzll(x));
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}
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#endif
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@ -315,12 +315,11 @@ pub fn addCases(cases: &tests.ParseCContext) {
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\\pub const LUA_GLOBALSINDEX = -10002;
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);
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cases.add("sift right assign",
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cases.add("shift right assign",
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\\int log2(unsigned a) {
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\\ int i = 0;
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\\ while (a > 0) {
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\\ a >>= 1;
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\\ //i++;
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\\ }
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\\ return i;
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\\}
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@ -334,4 +333,24 @@ pub fn addCases(cases: &tests.ParseCContext) {
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\\ return i;
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\\}
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);
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cases.add("shift right assign with a fixed size type",
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\\#include <stdint.h>
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\\int log2(uint32_t a) {
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\\ int i = 0;
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\\ while (a > 0) {
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\\ a >>= 1;
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\\ }
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\\ return i;
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\\}
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,
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\\export fn log2(_arg_a: u32) -> c_int {
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\\ var a = _arg_a;
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\\ var i: c_int = 0;
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\\ while (a > c_uint(0)) {
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\\ a >>= u5(1);
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\\ };
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\\ return i;
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\\}
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);
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}
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