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Hi,
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<div class="">A64 versus A32/T32 code generation is controlled by the -target option which I don’t believe is under discussion here.</div>
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<div class="">James<br class="">
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<blockquote type="cite" class="">
<div class="">On 18 May 2016, at 13:17, Bruce Hoult <<a href="mailto:bruce@hoult.org" class="">bruce@hoult.org</a>> wrote:</div>
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<div dir="ltr" class="">Note that armv8a modifies the A32 and T32 instruction sets, and is therefore an important -march option for 32 bit code. Therefore armv8a can not be used to imply aarch64.
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<div class="">For example:</div>
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<div class="">- IT predication instruction with more than a single controlled 16 bit instruction, or an instruction that modifies PC is deprecated. All old uses of IT work by default, but a control bit enables the OS to cause a trap on use of a deprecated use.</div>
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<div class="">- new A32 and T32 Load Acquire/Store Release instructions</div>
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<div class="">- new A32 and T32 scalar FP instructions including conditional select, min, max, new rounding modes for FP to int conversion, conversion between half precision and double precision</div>
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<div class="">- new A32 and T32 vector forms of the above FP operations</div>
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<div class="">- new A32 and T32 cryptographic instructions</div>
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<div class="">- changes to barrier instructions</div>
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<div class="">Users can reasonably expect -march=armv8a for 32 bit code to potentially generate the new FP instructions and restrict the use of the IT instruction.</div>
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<div class="gmail_extra"><br class="">
<div class="gmail_quote">On Thu, May 5, 2016 at 1:11 PM, Jojo Ma via llvm-dev <span dir="ltr" class="">
<<a href="mailto:llvm-dev@lists.llvm.org" target="_blank" class="">llvm-dev@lists.llvm.org</a>></span> wrote:<br class="">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<span class="">Hi everyone,</span><span class=""><br class="">
<br class="">
</span><span class="">I'm a member engineer of linaro's llvm team,coming from Spreadtrum.</span><span class=""><span class="">I am a new person on LLVM.</span>Now I'm writing a Target Parser for AArch64,so options parsing of AArch64 about cpu & arch & fpu can
be s</span><span class="">ummary to one place.<br class="">
<br class="">
</span><span class="">In the TargetParser,we assume "aarch64" and "arm64" are synonyms of armv8a(as they are only for armv8a,people usually do this). So after using AArch64TargetParser in options parsing in Clang,using "-march=aarch64" and "-march=arm64" are
both valid.<br class="">
<br class="">
</span><span class="">I saw Kevin </span><span class="">has a different view on this in his submission:r213353.<br class="">
<br class="">
</span></div>
<span style="color:rgb(56,118,29)" class=""><i class=""><span class="">+// RUN: %clang -target aarch64 -march=arm64 -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-ARCH-NOT-ACCEPT %s</span><br class="">
<span class="">+// RUN: %clang -target aarch64 -march=aarch64 -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-ARCH-NOT-ACCEPT %s</span><br class="">
<span class="">+// CHECK-ARCH-NOT-ACCEPT: error: the clang compiler does not support</span></i></span><br class="">
<div class="">
<div style="margin-left:40px" class=""><span class=""></span></div>
<span class=""><br class="">
So I failed on the </span><span class="">regression testing.</span><span class="">So I think we should reach a consensus on this issue.</span><span class=""><br class="">
Would you mind letting me know what you think of this issuse?<br class="">
<br class="">
</span><span class="">Thank you very much!</span><span class="">Looking forward to your reply!<br class="">
</span><span class="">I enclose the </span><span class=""><span class="">attachments</span> for your reference.<br class="">
<br class="">
</span><span class="">Best Regards,<br class="">
</span><span class=""><a href="http://Jojo.ma" class="">Jojo.ma</a></span></div>
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