Add macros for unaligned access #40
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vineetgarc
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No real reason, just the terminology I'm more used to from past. I can certainly respin with new verbiage. |
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riscv-c-api.md
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| A typical complier could (but not necessarily) map fast variant to -mno-strict-align | ||
| and bad to -mstrict-align, if specified. |
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I would like to drop that since clang has different behavior here, it just accept and ignore -mno-strict-align and -mstrict-align for RISC-V clang.
Or move it become a note to say GCC is using that way to decide which macro should be defined.
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Sorry not clear what you mean: clang ignores either of them ? and uses a different toggle to affect misaligned access codegen or doesn't support that at all (extremely unlikely)
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Sorry not clear what you mean: clang ignores either of them ? and uses a different toggle to affect misaligned access codegen or doesn't support that at all (extremely unlikely)
Yes, RISC-V clang accept that and then ignore that for now - clang did support misaligned code gen and some more are coming up[1], option handling in clang part can easily be implement/fix later.
Anyway just second thought about this: This should not major blocker issue here, just a minor implementation issue, and you already mention (but not necessarily).
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cc @asb @luismarques |
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I think from #32, @aswaterman was concerned that I had a slight preference for zicclsm even if it's not very comprehensible just to avoid introducing too many ways of saying the same thing. But I don't feel strongly enough to block this. I think we should wait for @aswaterman's feedback though, as he participated in the other thread. |
riscv-non-isa#32 Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
vineetgarc
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Fair enough. Updated pull request with bad -> avoid
I tend to disagree still, but we can agree to disagree :-)
Sure thing. |
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I'm OK with this scheme. I guess I agree with @asb in principle, but, like him, I don't think it's actually a problem, so I don't want to hold this up. |
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Thanks Andrew. Sounds like we have consensus on this then? LGTM. |
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Thanks @vineetgarc , gonna merge this :) |
RISC-V C API introduce predefined macro to achieve hints about unaligned accesses [0]. This defines __riscv_misaligned_fast when using -mno-strict-align, otherwise, defines __riscv_misaligned_avoid. Note: This ignores __riscv_misaligned_slow which is also defined by spec. The spec has mentioned riscv-non-isa/riscv-c-api-doc#40 [0]: riscv-non-isa/riscv-c-api-doc#40
…5756) RISC-V C API introduced predefined macro to achieve hints about unaligned accesses ([pr]). This patch defines __riscv_misaligned_fast when using -mno-strict-align, otherwise, defines __riscv_misaligned_avoid. Note: This ignores __riscv_misaligned_slow which is also defined by spec. [pr]: riscv-non-isa/riscv-c-api-doc#40
…vm#65756) RISC-V C API introduced predefined macro to achieve hints about unaligned accesses ([pr]). This patch defines __riscv_misaligned_fast when using -mno-strict-align, otherwise, defines __riscv_misaligned_avoid. Note: This ignores __riscv_misaligned_slow which is also defined by spec. [pr]: riscv-non-isa/riscv-c-api-doc#40
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