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Re: [patch 2/2][arm]: redefine aes patterns
- From: Kyrill Tkachov <kyrylo dot tkachov at foss dot arm dot com>
- To: Sylvia Taylor <Sylvia dot Taylor at arm dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Ramana Radhakrishnan <Ramana dot Radhakrishnan at arm dot com>
- Cc: nd <nd at arm dot com>
- Date: Tue, 9 Jul 2019 10:28:57 +0100
- Subject: Re: [patch 2/2][arm]: redefine aes patterns
- References: <AM6PR08MB3559AC777251970CC7AFC7B9E0F50@AM6PR08MB3559.eurprd08.prod.outlook.com>
Hi Sylvia,
On 7/5/19 12:32 PM, Sylvia Taylor wrote:
Greetings,
This patch removes the arch-common aese/aesmc and aesd/aesimc fusions
(i.e. aes fusion) implemented in the scheduling phase through the
aarch_crypto_can_dual function. The reason is due to observing
undesired behaviour in cases such as:
- when register allocation goes bad (e.g. extra movs)
- aes operations with xor and zeroed keys among interleaved operations
A more stable version should be provided by instead doing the aes fusion
during the combine pass. As such, new combine patterns have been added to
enable this.
The second change is the aese and aesd patterns have been rewritten as
encapsulating a xor operation. The purpose is to simplify the need of
having additional combine patterns for cases like the ones below:
For AESE (though it also applies to AESD as both have a xor operation):
data = data ^ key;
data = vaeseq_u8(data, zero);
---
veor q1, q0, q1
aese.8 q1, q9
Should mean and generate the same as:
data = vaeseq_u8(data, key);
---
aese.8 q1, q0
Bootstrapped and tested on arm-none-linux-gnueabihf.
Thanks! This looks much cleaner now.
Committed on your behalf with r273296.
Kyrill
Cheers,
Syl
gcc/ChangeLog:
2019-07-05 Sylvia Taylor <sylvia.taylor@arm.com>
* config/arm/crypto.md:
(crypto_<crypto_pattern>): Redefine aese/aesd pattern with xor.
(crypto_<crypto_pattern>): Remove attribute enabled for aesmc.
(crypto_<crypto_pattern>): Split CRYPTO_BINARY into 2 patterns.
(*aarch32_crypto_aese_fused, *aarch32_crypto_aesd_fused): New.
* config/arm/arm.c
(aarch_macro_fusion_pair_p): Remove aes/aesmc fusion check.
* config/arm/aarch-common-protos.h
(aarch_crypto_can_dual_issue): Remove.
* config/arm/aarch-common.c
(aarch_crypto_can_dual_issue): Likewise.
* config/arm/exynos-m1.md: Remove aese/aesmc fusion.
* config/arm/cortex-a53.md: Likewise.
* config/arm/cortex-a57.md: Likewise.
* config/arm/iterators.md:
(CRYPTO_BINARY): Redefine.
(CRYPTO_UNARY): Removed.
(CRYPTO_AES, CRYPTO_AESMC): New.
gcc/testsuite/ChangeLog:
2019-07-05 Sylvia Taylor <sylvia.taylor@arm.com>
* gcc.target/arm/aes-fuse-1.c: New.
* gcc.target/arm/aes-fuse-2.c: New.
* gcc.target/arm/aes_xor_combine.c: New.