[LLVMbugs] [Bug 19546] New: missed-optimization: copies of adjacent struct fields are not coalesced

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=19546

            Bug ID: 19546
           Summary: missed-optimization: copies of adjacent struct fields
                    are not coalesced
           Product: clang
           Version: 3.4
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: LLVM Codegen
          Assignee: unassignedclangbugs at nondot.org
          Reporter: luto at mit.edu
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

For every optimization setting I've tried, clang 3.4 generates two two-byte
copies for this code:

struct test
{
  unsigned short a, b;
};

void copy_test(struct test * __restrict__ out,
           const struct test * __restrict__ in)
{
  out->a = in->a;
  out->b = in->b;
}

It should generate the same code it does for *out = *in.

Sorry if I'm targetting the wrong component.

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