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<body><span class="vcard"><a class="email" href="mailto:david.majnemer@gmail.com" title="David Majnemer <david.majnemer@gmail.com>"> <span class="fn">David Majnemer</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Overestimated align on load"
href="https://bugs.llvm.org/show_bug.cgi?id=32230">bug 32230</a>
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<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">CC</td>
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<td>david.majnemer@gmail.com
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<td style="text-align:right;">Status</td>
<td>NEW
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<td>RESOLVED
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<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>INVALID
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Overestimated align on load"
href="https://bugs.llvm.org/show_bug.cgi?id=32230#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Overestimated align on load"
href="https://bugs.llvm.org/show_bug.cgi?id=32230">bug 32230</a>
from <span class="vcard"><a class="email" href="mailto:david.majnemer@gmail.com" title="David Majnemer <david.majnemer@gmail.com>"> <span class="fn">David Majnemer</span></a>
</span></b>
<pre>This works as intended, the compiler is obligated to use the alignment of
uint64_t for the load which, in this case, is eight bytes.
If you want to achieve the desired effect, do the following instead:
#include <cstdint>
#include <cstring>
using namespace std;
void test(uint8_t *ptr, long *buf, int const N) {
for (int I = 0; I < N - 7; ++I) {
uint64_t big;
memcpy(&big, ptr + I, sizeof(big));
buf[I] = big * big;
}
}
In the IR, you will now see something along the lines of:
%14 = load i64, i64* %13, align 1</pre>
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