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<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">Hi, All developers:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">I have this code. For (*b)[2], It is reasonable that llvm thinks it's unaligned access. and I think the array pointer always points to 4 - byte aligned
array elements.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><img width="192" height="82" id="_x56fe__x7247__x0020_1" src="cid:image001.png@01D61C07.2E95DB10"></span><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">CMD: clang --target=arm-none-eabi -mcpu=cortex-r52 -mthumb -O0 -emit-llvm -S test.c -o test.ll<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">LLVM think it’s an align 1 store, I don't think so.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><img width="648" height="227" id="_x56fe__x7247__x0020_2" src="cid:image002.png@01D61C08.6DC76AF0"></span><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">CMD: llc -mattr=+strict-align test.ll<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">If the CPU does not support non-aligned access, The access is divided into four one-byte access.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><img width="228" height="118" id="_x56fe__x7247__x0020_3" src="cid:image003.png@01D61C09.E2D82DB0"></span><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">CMD: llc -mattr=-strict-align test.ll<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">If the CPU support non-aligned access, It's a normal four-byte access.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><img width="272" height="66" id="_x56fe__x7247__x0020_5" src="cid:image004.png@01D61C0A.F65032B0"></span><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">But gcc always think it’s an aligned access ,and processed him as a four-byte access. I think this is reasonable.<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">CMD1: arm-none-eabi-gcc -mcpu=cortex-r52 -mthumb -munaligned-access -O0 -emit-llvm -S test.c -o test.s<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">CMD2: arm-none-eabi-gcc -mcpu=cortex-r52 -mthumb -mno-unaligned-access -O0 -emit-llvm -S test.c -o test.s<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><img width="235" height="77" id="_x56fe__x7247__x0020_6" src="cid:image005.png@01D61C0B.34493800"></span><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#666666">Why does LLVM think it's a one-byte-aligned access? I think it makes more sense to access the number of aligned based on the type of the array element
to which the array pointer points</span><span lang="EN-US"><o:p></o:p></span></b></p>
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