mk: Request -march=i686 on i686 Linux #34578
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Apparently the gcc on our dist bot is so old and/or obscure that the default `-m32` switch doesn't think it can generate i686 code (or something like that). The compiler-rt build system probes for the `__i686__` define in GCC to compile for an i686 (vs i386) target, so this was failing on the bots. This tweaks instead to pass `-march=i686` on i686-unknown-linux-gnu to C code to ensure that we're compiling for i686 instead of i386. This should hopefully not actually have an impact other than maybe doing some random optimization it wasn't able to do so before. In theory this isn't making the target less compatible as all Rust code is already compiled for i686. Hopefully closes rust-lang#34572
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r? @brson (rust_highfive has picked a reviewer for you, use r? to override) |
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@bors r+ p=1 |
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📌 Commit ab06ace has been approved by |
In practice we do distribute builds for targets like OTOH this PR is correct since it only tweaks flags for a i686 linux target, but I feel like you may want to pass such flag for other i686 targets as well. |
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Yes that's why I just changed this for i686-unknown-linux-gnu and not others. It doesn't really matter in the long run anyway because we have essentially no C code to begin with, this is purely just getting the nightlies working again. |
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⌛ Testing commit ab06ace with merge a89ce32... |
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💔 Test failed - auto-linux-64-x-android-t |
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@bors retry |
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💔 Test failed - auto-win-msvc-64-opt-rustbuild |
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💔 Test failed - auto-linux-64-x-android-t |
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@bors: retry
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⌛ Testing commit ab06ace with merge 9436292... |
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💔 Test failed - auto-win-msvc-64-opt-rustbuild |
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@bors: retry On Fri, Jul 1, 2016 at 12:17 PM, bors [email protected] wrote:
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…nightlies, r=brson mk: Request -march=i686 on i686 Linux Apparently the gcc on our dist bot is so old and/or obscure that the default `-m32` switch doesn't think it can generate i686 code (or something like that). The compiler-rt build system probes for the `__i686__` define in GCC to compile for an i686 (vs i386) target, so this was failing on the bots. This tweaks instead to pass `-march=i686` on i686-unknown-linux-gnu to C code to ensure that we're compiling for i686 instead of i386. This should hopefully not actually have an impact other than maybe doing some random optimization it wasn't able to do so before. In theory this isn't making the target less compatible as all Rust code is already compiled for i686. Hopefully closes #34572
Apparently the gcc on our dist bot is so old and/or obscure that the default
-m32switch doesn't think it can generate i686 code (or something like that).The compiler-rt build system probes for the
__i686__define in GCC to compilefor an i686 (vs i386) target, so this was failing on the bots.
This tweaks instead to pass
-march=i686on i686-unknown-linux-gnu to C code toensure that we're compiling for i686 instead of i386. This should hopefully not
actually have an impact other than maybe doing some random optimization it
wasn't able to do so before. In theory this isn't making the target less
compatible as all Rust code is already compiled for i686.
Hopefully closes #34572