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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a question about LoopVectorize. I wrote a simple test case, a dot product loop and found that packed instructions are generated when input arrays are integer, but not when they are float or double.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">If I modify the float example in <a href="http://llvm.org/docs/Vectorizers.html">
http://llvm.org/docs/Vectorizers.html</a> by adding restrict to the input arrays packed instructions are generated. Although it should not be required I tried doing the same to the input arrays of my dot product example but it still doesn’t generate packed
float or double instructions.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is the loop vectorizer supposed to generate packed float and double instructions? Is this a bug, or am I doing something wrong?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Tyler<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">float dotproduct(float *A, float *B, int n) {<o:p></o:p></p>
<p class="MsoNormal"> float sum = 0;<o:p></o:p></p>
<p class="MsoNormal"> for(int i = 0; i < n; ++i) {<o:p></o:p></p>
<p class="MsoNormal"> sum += A[i] * B[i];<o:p></o:p></p>
<p class="MsoNormal"> }<o:p></o:p></p>
<p class="MsoNormal"> return sum;<o:p></o:p></p>
<p class="MsoNormal">}<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">clang dotproduct.cpp -O3 -fvectorize -march=atom -S -o -<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><loop body><o:p></o:p></p>
<p class="MsoNormal">.LBB1_1:<o:p></o:p></p>
<p class="MsoNormal"> movss (%rdi), %xmm1<o:p></o:p></p>
<p class="MsoNormal"> addq $4, %rdi<o:p></o:p></p>
<p class="MsoNormal"> mulss (%rsi), %xmm1<o:p></o:p></p>
<p class="MsoNormal"> addq $4, %rsi<o:p></o:p></p>
<p class="MsoNormal"> decl %edx<o:p></o:p></p>
<p class="MsoNormal"> addss %xmm1, %xmm0<o:p></o:p></p>
<p class="MsoNormal"> jne .LBB1_1<o:p></o:p></p>
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