[PATCH] Enhance optimize_atomic_bit_test_and to handle truncation.

Jeff Law jeffreyalaw@gmail.com
Tue Nov 23 17:56:59 GMT 2021



On 11/16/2021 10:20 PM, liuhongt via Gcc-patches wrote:
> r12-5102-gfb161782545224f5 improves integer bit test on
> __atomic_fetch_[or|and]_* returns only for nop_convert, .i.e.
>
> transfrom
>
>    mask_5 = 1 << bit_4(D);
>    mask.0_1 = (unsigned int) mask_5;
>    _2 = __atomic_fetch_or_4 (a_7(D), mask.0_1, 0);
>    t1_9 = (int) _2;
>    t2_10 = mask_5 & t1_9;
>
> to
>
>    mask_5 = 1 << n_4(D);
>    mask.1_1 = (unsigned int) mask_5;
>    _11 = .ATOMIC_BIT_TEST_AND_SET (&pscc_a_1_4, n_4(D), 0);
>    _8 = (int) _11;
>
> And this patch extend the original patch to handle truncation.
> .i.e.
>
> transform
>
>    long int mask;
>    mask_8 = 1 << n_7(D);
>    mask.0_1 = (long unsigned int) mask_8;
>    _2 = __sync_fetch_and_or_8 (&pscc_a_2_3, mask.0_1);
>    _3 = (unsigned int) _2;
>    _4 = (unsigned int) mask_8;
>    _5 = _3 & _4;
>    _6 = (int) _5;
>
> to
>
>    long int mask;
>    mask_8 = 1 << n_7(D);
>    mask.0_1 = (long unsigned int) mask_8;
>    _14 = .ATOMIC_BIT_TEST_AND_SET (&pscc_a_2_3, n_7(D), 0);
>    _5 = (unsigned int) _14;
>    _6 = (int) _5;
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}
> Ok for trunk?
>
> 2021-11-17  Hongtao Liu  <hongtao.liu@intel.com>
> 	    H.J. Lu  <hongjiu.lu@intel.com>
>
> gcc/ChangeLog:
>
> 	PR tree-optimization/103194
> 	* match.pd (gimple_nop_atomic_bit_test_and_p): Extended to
> 	match truncation.
> 	* tree-ssa-ccp.c (gimple_nop_convert): Declare.
> 	(optimize_atomic_bit_test_and): Enhance
> 	optimize_atomic_bit_test_and to handle truncation.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/i386/pr103194-2.c: New test.
> 	* gcc.target/i386/pr103194-3.c: New test.
> 	* gcc.target/i386/pr103194-4.c: New test.
> 	* gcc.target/i386/pr103194-5.c: New test.
> 	* gcc.target/i386/pr103194.c: New test.
OK
jeff



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