[PATCH] D107605: [MemCpyOpt] Teach memcpyopt to handle loads from the constant memory.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Makes sense.



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Comment at: llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp:1571
+                     MemoryLocation::getForSource(M)) &&
+      !AA->pointsToConstantMemory(MemoryLocation::getForSource(M)))
     return false;
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Is it possible to write this using getModRefInfo()?  Something like `if (isModSet(AA->getModRefInfo(M, MemoryLocation::getForSource(M))))`.


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Comment at: llvm/test/Transforms/MemCpyOpt/memset-memcpy-redundant-memset.ll:21
+  call void @llvm.memset.p0i8.i64(i8* %dst, i8 %c, i64 %dst_size, i1 false)
+  %src = getelementptr inbounds [0 x i8], [0 x i8]* @C, i64 0, i64 undef
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 %src_size, i1 false)
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Please don't use undef here, or in the other tests.  It might lead to confusing results in the future.


Repository:
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https://reviews.llvm.org/D107605