[LLVMbugs] [Bug 5265] New: Non native ext vector types have non aligned sizes

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=5265

           Summary: Non native ext vector types have non aligned sizes
           Product: clang
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: LLVM Codegen
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: holm at liacs.nl
                CC: llvmbugs at cs.uiuc.edu


Assume a three element vector type like:

typedef float __attribute__((ext_vector_type (3))) float3;

Then sizeof(float3) == 12, which make sense if you just add the sizeof(float).
However, this unfortunately means that an array of float3 cannot be loaded into
SSE registers as those require aligned memory accesses.

At least for 3 element float vectors that fit nicely into SSE registers, it
would be a big plus if non native vectors were padded for alignment and thus
made SSE compatible.


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