47601815ec
Some CPUs do not allow memory accesses to be unaligned, e.g. 2k1000la who uses the la264 core on which misaligned access will trigger an exception. In this patch, a backend feature called `ual` is defined to decribe whether the CPU supports unaligned memroy accesses. And this feature can be toggled by clang options `-m[no-]unaligned-access` or the aliases `-m[no-]strict-align`. When this feature is on, `allowsMisalignedMemoryAccesses` sets the speed number to 1 and returns true that allows the codegen to generate unaligned memory access insns. Clang options `-m[no-]unaligned-access` are moved from `m_arm_Features_Group` to `m_Group` because now more than one targets use them. And a test is added to show that they remain unused on a target that does not support them. In addition, to keep compatible with gcc, a new alias `-mno-strict-align` is added which is equal to `-munaligned-access`. The feature name `ual` is consistent with linux kernel [1] and the output of `lscpu` or `/proc/cpuinfo` [2]. There is an `LLT` variant of `allowsMisalignedMemoryAccesses`, but seems that curently it is only used in GlobalISel which LoongArch doesn't support yet. So this variant is not implemented in this patch. [1]: https://github.com/torvalds/linux/blob/master/arch/loongarch/include/asm/cpu.h#L77 [2]: https://github.com/torvalds/linux/blob/master/arch/loongarch/kernel/proc.c#L75 Reviewed By: xen0n Differential Revision: https://reviews.llvm.org/D149946 |
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| cross-project-tests | ||
| flang | ||
| libc | ||
| libclc | ||
| libcxx | ||
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| lld | ||
| lldb | ||
| llvm | ||
| llvm-libgcc | ||
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| .git-blame-ignore-revs | ||
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| .mailmap | ||
| CONTRIBUTING.md | ||
| LICENSE.TXT | ||
| README.md | ||
| SECURITY.md | ||
The LLVM Compiler Infrastructure
Welcome to the LLVM project!
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