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GH-139757: JIT: Remove redundant branches to jumps in the assembly optimizer #140800

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GH-139757: JIT: Remove redundant branches to jumps in the assembly optimizer #140800

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7 changes: 4 additions & 3 deletions Python/bytecodes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -982,9 +982,10 @@ dummy_func(
DEOPT_IF(!_PyLong_IsNonNegativeCompact((PyLongObject *)sub));
Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
DEOPT_IF(PyUnicode_GET_LENGTH(str) <= index);
// Specialize for reading an ASCII character from any string:
Py_UCS4 c = PyUnicode_READ_CHAR(str, index);
DEOPT_IF(Py_ARRAY_LENGTH(_Py_SINGLETON(strings).ascii) <= c);
// Specialize for reading an ASCII character from an ASCII string:
DEOPT_IF(!PyUnicode_IS_COMPACT_ASCII(str));
uint8_t c = PyUnicode_1BYTE_DATA(str)[index];
assert(c < 128);
STAT_INC(BINARY_OP, hit);
PyObject *res_o = (PyObject*)&_Py_SINGLETON(strings).ascii[c];
PyStackRef_CLOSE_SPECIALIZED(sub_st, _PyLong_ExactDealloc);
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5 changes: 3 additions & 2 deletions Python/executor_cases.c.h
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5 changes: 3 additions & 2 deletions Python/generated_cases.c.h
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3 changes: 2 additions & 1 deletion Python/jit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,7 @@ set_bits(uint32_t *loc, uint8_t loc_start, uint64_t value, uint8_t value_start,
#define IS_AARCH64_ADRP(I) (((I) & 0x9F000000) == 0x90000000)
#define IS_AARCH64_BRANCH(I) (((I) & 0x7C000000) == 0x14000000)
#define IS_AARCH64_BRANCH_COND(I) (((I) & 0x7C000000) == 0x54000000)
#define IS_AARCH64_BRANCH_ZERO(I) (((I) & 0x7E000000) == 0x34000000)
#define IS_AARCH64_TEST_AND_BRANCH(I) (((I) & 0x7E000000) == 0x36000000)
#define IS_AARCH64_LDR_OR_STR(I) (((I) & 0x3B000000) == 0x39000000)
#define IS_AARCH64_MOV(I) (((I) & 0x9F800000) == 0x92800000)
Expand Down Expand Up @@ -348,7 +349,7 @@ void
patch_aarch64_19r(unsigned char *location, uint64_t value)
{
uint32_t *loc32 = (uint32_t *)location;
assert(IS_AARCH64_BRANCH_COND(*loc32));
assert(IS_AARCH64_BRANCH_COND(*loc32) || IS_AARCH64_BRANCH_ZERO(*loc32));
value -= (uintptr_t)location;
// Check that we're not out of range of 21 signed bits:
assert((int64_t)value >= -(1 << 20));
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2 changes: 2 additions & 0 deletions Tools/cases_generator/analyzer.py
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Expand Up @@ -614,6 +614,8 @@ def has_error_without_pop(op: parser.CodeDef) -> bool:
"PyUnicode_Concat",
"PyUnicode_GET_LENGTH",
"PyUnicode_READ_CHAR",
"PyUnicode_IS_COMPACT_ASCII",
"PyUnicode_1BYTE_DATA",
"Py_ARRAY_LENGTH",
"Py_FatalError",
"Py_INCREF",
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