On 5/24/24 2:41 AM, Mariam Arutunian wrote:
This patch introduces new built-in functions to GCC for computing bit-
forward and bit-reversed CRCs.
These builtins aim to provide efficient CRC calculation capabilities.
When the target architecture supports CRC operations (as indicated by
the presence of a CRC optab),
the builtins will utilize the expander to generate CRC code.
In the absence of hardware support, the builtins default to generating
code for a table-based CRC calculation.
The builtins are defined as follows:
__builtin_rev_crc16_data8,
__builtin_rev_crc32_data8, __builtin_rev_crc32_data16,
__builtin_rev_crc32_data32
__builtin_crc8_data8,
__builtin_crc16_data16, __builtin_crc16_data8,
__builtin_crc32_data8, __builtin_crc32_data16, __builtin_crc32_data32,
__builtin_crc64_data8, __builtin_crc64_data16, __builtin_crc64_data32,
__builtin_crc64_data64
Each builtin takes three parameters:
crc: The initial CRC value.
data: The data to be processed.
polynomial: The CRC polynomial without the leading 1.
To validate the correctness of these builtins, this patch also includes
additions to the GCC testsuite.
This enhancement allows GCC to offer developers high-performance CRC
computation options
that automatically adapt to the capabilities of the target hardware.
Co-authored-by: Joern Rennecke <joern.renne...@embecosm.com
<mailto:joern.renne...@embecosm.com>>
Not complete. May continue the work if these built-ins are needed.
gcc/
* builtin-types.def (BT_FN_UINT8_UINT8_UINT8_CONST_SIZE): Define.
(BT_FN_UINT16_UINT16_UINT8_CONST_SIZE): Likewise.
(BT_FN_UINT16_UINT16_UINT16_CONST_SIZE): Likewise.
(BT_FN_UINT32_UINT32_UINT8_CONST_SIZE): Likewise.
(BT_FN_UINT32_UINT32_UINT16_CONST_SIZE): Likewise.
(BT_FN_UINT32_UINT32_UINT32_CONST_SIZE): Likewise.
(BT_FN_UINT64_UINT64_UINT8_CONST_SIZE): Likewise.
(BT_FN_UINT64_UINT64_UINT16_CONST_SIZE): Likewise.
(BT_FN_UINT64_UINT64_UINT32_CONST_SIZE): Likewise.
(BT_FN_UINT64_UINT64_UINT64_CONST_SIZE): Likewise.
* builtins.cc (associated_internal_fn): Handle
BUILT_IN_CRC8_DATA8,
BUILT_IN_CRC16_DATA8, BUILT_IN_CRC16_DATA16,
BUILT_IN_CRC32_DATA8, BUILT_IN_CRC32_DATA16,
BUILT_IN_CRC32_DATA32,
BUILT_IN_CRC64_DATA8, BUILT_IN_CRC64_DATA16,
BUILT_IN_CRC64_DATA32,
BUILT_IN_CRC64_DATA64,
BUILT_IN_REV_CRC8_DATA8,
BUILT_IN_REV_CRC16_DATA8, BUILT_IN_REV_CRC16_DATA16,
BUILT_IN_REV_CRC32_DATA8, BUILT_IN_REV_CRC32_DATA16,
BUILT_IN_REV_CRC32_DATA32.
(expand_builtin_crc_table_based): New function.
(expand_builtin): Handle BUILT_IN_CRC8_DATA8,
BUILT_IN_CRC16_DATA8, BUILT_IN_CRC16_DATA16,
BUILT_IN_CRC32_DATA8, BUILT_IN_CRC32_DATA16,
BUILT_IN_CRC32_DATA32,
BUILT_IN_CRC64_DATA8, BUILT_IN_CRC64_DATA16,
BUILT_IN_CRC64_DATA32,
BUILT_IN_CRC64_DATA64,
BUILT_IN_REV_CRC8_DATA8,
BUILT_IN_REV_CRC16_DATA8, BUILT_IN_REV_CRC16_DATA16,
BUILT_IN_REV_CRC32_DATA8, BUILT_IN_REV_CRC32_DATA16,
BUILT_IN_REV_CRC32_DATA32.
* builtins.def (BUILT_IN_CRC8_DATA8): New builtin.
(BUILT_IN_CRC16_DATA8): Likewise.
(BUILT_IN_CRC16_DATA16): Likewise.
(BUILT_IN_CRC32_DATA8): Likewise.
(BUILT_IN_CRC32_DATA16): Likewise.
(BUILT_IN_CRC32_DATA32): Likewise.
(BUILT_IN_CRC64_DATA8): Likewise.
(BUILT_IN_CRC64_DATA16): Likewise.
(BUILT_IN_CRC64_DATA32): Likewise.
(BUILT_IN_CRC64_DATA64): Likewise.
(BUILT_IN_REV_CRC8_DATA8): New builtin.
(BUILT_IN_REV_CRC16_DATA8): Likewise.
(BUILT_IN_REV_CRC16_DATA16): Likewise.
(BUILT_IN_REV_CRC32_DATA8): Likewise.
(BUILT_IN_REV_CRC32_DATA16): Likewise.
(BUILT_IN_REV_CRC32_DATA32): Likewise.
* builtins.h (expand_builtin_crc_table_based): New function
declaration.
* doc/extend.texti (__builtin_rev_crc16_data8,
(__builtin_rev_crc32_data32, __builtin_rev_crc32_data8,
__builtin_rev_crc32_data16, __builtin_crc8_data8,
__builtin_crc16_data16, __builtin_crc16_data8,
__builtin_crc32_data32, __builtin_crc32_data8,
__builtin_crc32_data16, __builtin_crc64_data64,
__builtin_crc64_data8, __builtin_crc64_data16,
__builtin_crc64_data32): Document.
gcc/testsuite/
* gcc.c-torture/compile/crc-builtin-rev-target32.c
* gcc.c-torture/compile/crc-builtin-rev-target64.c
* gcc.c-torture/compile/crc-builtin-target32.c
* gcc.c-torture/compile/crc-builtin-target64.c
Signed-off-by: Mariam Arutunian <mariamarutun...@gmail.com
<mailto:mariamarutun...@gmail.com>>
diff --git a/gcc/builtins.cc b/gcc/builtins.cc
index f8d94c4b435..b662de91e49 100644
--- a/gcc/builtins.cc
+++ b/gcc/builtins.cc
@@ -2207,7 +2207,24 @@ associated_internal_fn (built_in_function fn, tree
return_type)
if (REAL_MODE_FORMAT (TYPE_MODE (return_type))->b == 2)
return IFN_LDEXP;
return IFN_LAST;
-
+ case BUILT_IN_CRC8_DATA8:
+ case BUILT_IN_CRC16_DATA8:
+ case BUILT_IN_CRC16_DATA16:
+ case BUILT_IN_CRC32_DATA8:
+ case BUILT_IN_CRC32_DATA16:
+ case BUILT_IN_CRC32_DATA32:
+ case BUILT_IN_CRC64_DATA8:
+ case BUILT_IN_CRC64_DATA16:
+ case BUILT_IN_CRC64_DATA32:
+ case BUILT_IN_CRC64_DATA64:
+ return IFN_CRC;
+ case BUILT_IN_REV_CRC8_DATA8:
+ case BUILT_IN_REV_CRC16_DATA8:
+ case BUILT_IN_REV_CRC16_DATA16:
+ case BUILT_IN_REV_CRC32_DATA8:
+ case BUILT_IN_REV_CRC32_DATA16:
+ case BUILT_IN_REV_CRC32_DATA32:
+ return IFN_CRC_REV;
So no REV_CRC64? Just want to make sure it's intentional and not an
oversight.
@@ -7751,6 +7768,37 @@ expand_speculation_safe_value (machine_mode mode, tree
exp, rtx target,
return targetm.speculation_safe_value (mode, target, val, failsafe);
}
+/* Expand CRC* or REV_CRC* built-ins. */
+
+rtx
+expand_builtin_crc_table_based (internal_fn fn, machine_mode data_mode,
+ machine_mode crc_mode, machine_mode mode,
+ tree exp, rtx target)
Line up parameters.
+{
+ tree rhs1 = CALL_EXPR_ARG (exp, 0); // crc
+ tree rhs2 = CALL_EXPR_ARG (exp, 1); // data
+ tree rhs3 = CALL_EXPR_ARG (exp, 2); // polynomial
+
+ gcc_assert (word_mode >= crc_mode);
+
+ if (!target || mode == VOIDmode)
+ target = gen_reg_rtx (crc_mode);
I'm kindof curious, did we ever see a case where mode was VOIDmode?
Would that check be better as a gcc_assert?
+
+ rtx op1 = expand_normal (rhs1);
+ rtx op2 = expand_normal (rhs2);
+ gcc_assert (TREE_CODE (rhs3) == INTEGER_CST);
+ rtx op3 = gen_rtx_CONST_INT (crc_mode, TREE_INT_CST_LOW (rhs3));
I think we probably want to use gen_int_mode rather than gen_rtx_CONST_INT.
diff --git a/gcc/builtins.h b/gcc/builtins.h
index 8d93f75a9a4..e94dec68ed2 100644
--- a/gcc/builtins.h
+++ b/gcc/builtins.h
@@ -133,6 +133,9 @@ extern void expand_builtin_trap (void);
extern void expand_ifn_atomic_bit_test_and (gcall *);
extern void expand_ifn_atomic_compare_exchange (gcall *);
extern void expand_ifn_atomic_op_fetch_cmp_0 (gcall *);
+extern rtx expand_builtin_crc_table_based (internal_fn, machine_mode,
+ machine_mode, machine_mode,
+ tree, rtx);
The usual formatting nit here :-)
Generally pretty good. Please repost after fixing the issues noted
above. Thanks.
jeff
