Identified regression caused by *llvm:09507b53250dc266632c204558cb1c2b56e8ddea*: commit 09507b53250dc266632c204558cb1c2b56e8ddea Author: Cullen Rhodes cullen.rhodes@arm.com

[AArch64][SME] Disable NEON in streaming mode

Results regressed to (for first_bad == 09507b53250dc266632c204558cb1c2b56e8ddea) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1 -- --set gcc_override_configure=--with-mode=arm --set gcc_override_configure=--disable-libsanitizer: -8 # build_abe linux: -7 # build_abe glibc: -6 # build_abe stage2 -- --set gcc_override_configure=--with-mode=arm --set gcc_override_configure=--disable-libsanitizer: -5 # build_llvm true: -3 # true: 0 # benchmark -- -O3_marm artifacts/build-09507b53250dc266632c204558cb1c2b56e8ddea/results_id: 1 # 456.hmmer,hmmer_base.default regressed by 103

from (for last_good == 93c55d5ea24b8f455b0621bac373f142e0008739) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1 -- --set gcc_override_configure=--with-mode=arm --set gcc_override_configure=--disable-libsanitizer: -8 # build_abe linux: -7 # build_abe glibc: -6 # build_abe stage2 -- --set gcc_override_configure=--with-mode=arm --set gcc_override_configure=--disable-libsanitizer: -5 # build_llvm true: -3 # true: 0 # benchmark -- -O3_marm artifacts/build-93c55d5ea24b8f455b0621bac373f142e0008739/results_id: 1

This commit has regressed these CI configurations: - tcwg_bmk_llvm_tk1/llvm-master-arm-spec2k6-O3

Artifacts of last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a... Artifacts of first_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a... Even more details: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a...

Reproduce builds: <cut> mkdir investigate-llvm-09507b53250dc266632c204558cb1c2b56e8ddea cd investigate-llvm-09507b53250dc266632c204558cb1c2b56e8ddea

# Fetch scripts git clone https://git.linaro.org/toolchain/jenkins-scripts

# Fetch manifests and test.sh script mkdir -p artifacts/manifests curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a... --fail curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a... --fail curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tk1-llvm-master-a... --fail chmod +x artifacts/test.sh

# Reproduce the baseline build (build all pre-requisites) ./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh

# Save baseline build state (which is then restored in artifacts/test.sh) mkdir -p ./bisect rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /llvm/ ./ ./bisect/baseline/

cd llvm

# Reproduce first_bad build git checkout --detach 09507b53250dc266632c204558cb1c2b56e8ddea ../artifacts/test.sh

# Reproduce last_good build git checkout --detach 93c55d5ea24b8f455b0621bac373f142e0008739 ../artifacts/test.sh

cd .. </cut>

Full commit (up to 1000 lines): <cut> commit 09507b53250dc266632c204558cb1c2b56e8ddea Author: Cullen Rhodes cullen.rhodes@arm.com Date: Mon Aug 16 07:31:55 2021 +0000

[AArch64][SME] Disable NEON in streaming mode

In streaming mode most of the NEON instruction set is illegal, disable NEON when compiling with `+streaming-sve`, unless NEON is explictly requested.

Subsequent patches will add support for the small subset of NEON instructions that are legal in streaming mode.

Reviewed By: paulwalker-arm, david-arm

Differential Revision: https://reviews.llvm.org/D107902 --- llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp | 11 ++++++++++- llvm/test/MC/AArch64/SME/streaming-sve-feature.s | 8 ++++++++ 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp index 3c2df1621e11..987cabce6cc9 100644 --- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp +++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp @@ -57,7 +57,16 @@ createAArch64MCSubtargetInfo(const Triple &TT, StringRef CPU, StringRef FS) { CPU = "apple-a12"; }

- return createAArch64MCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FS); + // Most of the NEON instruction set isn't supported in streaming mode on SME + // targets, disable NEON unless explicitly requested. + bool RequestedNEON = FS.contains("neon"); + bool RequestedStreamingSVE = FS.contains("streaming-sve"); + MCSubtargetInfo *STI = + createAArch64MCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FS); + if (RequestedStreamingSVE && !RequestedNEON && + STI->hasFeature(AArch64::FeatureNEON)) + STI->ToggleFeature(AArch64::FeatureNEON); + return STI; }

void AArch64_MC::initLLVMToCVRegMapping(MCRegisterInfo *MRI) { diff --git a/llvm/test/MC/AArch64/SME/streaming-sve-feature.s b/llvm/test/MC/AArch64/SME/streaming-sve-feature.s new file mode 100644 index 000000000000..e35505ca39c5 --- /dev/null +++ b/llvm/test/MC/AArch64/SME/streaming-sve-feature.s @@ -0,0 +1,8 @@ +// RUN: llvm-mc -triple=aarch64 -mattr=+streaming-sve,+neon < %s 2>&1 | FileCheck %s +// RUN: not llvm-mc -triple=aarch64 -mattr=+streaming-sve < %s 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR + +// Verify NEON is disabled when targeting streaming mode, if it's not +// explicitly requested. +add v0.8b, v1.8b, v2.8b +// CHECK: add v0.8b, v1.8b, v2.8b +// CHECK-ERROR: error: instruction requires: neon </cut>