[PATCH] D136822: [InstCombine] Allow memcpys from constant memory to readonly noalias parameters to be elided.

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: compiler-rt/test/asan/TestCases/printf-5.c:22
+  for (unsigned i = 0; i < sizeof(fmt); i++)
+    fmt[i] = "%c %d %f %s\n"[i];
   printf((char *)fmt, c, x, f, s);
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I'm really confused by what this test is trying to do with the memcpy here. Would the test pass with just `volatile char fmt[2] = "%c"`? That'll produce a volatile memcpy, and that shouldn't get optimized away.


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Comment at: llvm/test/Transforms/InstCombine/memcpy-from-global.ll:350
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %A, ptr align 4 @H, i64 20, i1 false)
+  call void @readonly_nocapture(ptr nocapture readonly %A)
+  ret void
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This can be `call void @bar(ptr nocapture readonly %A)`. We don't need separate functions and can vary the attributes at the call-site only. Same below.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D136822/new/

https://reviews.llvm.org/D136822