[LLVMbugs] [Bug 10441] New: LLVM Function with structure parameter is not compatible with VS2010

bugzilla-daemon at llvm.org bugzilla-daemon at llvm.org
Fri Jul 22 04:37:18 PDT 2011


           Summary: LLVM Function with structure parameter is not
                    compatible with VS2010
           Product: new-bugs
           Version: 2.9
          Platform: PC
        OS/Version: Windows NT
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: wuye9036 at gmail.com
                CC: llvmbugs at cs.uiuc.edu

Hi, I was wrote a function as following:


%float3 = <{float, float, float}>

define float dot_prod( %float3 %lhs, %float3 %rhs ){
    //  blah blah blah


And I have a function to invoke it:


struct float3{ float x, y, z; };

float3 a, b;
// Initialize a,b

// get JIT-ed pointer

float r = dot_prod( a, b ); // *ERROR*.


That's disassembly told us:


110:     float f = test_dot_f3(lhs, rhs);
000000013FEBF4A1  lea         rax,[rsp+1D8h]  
000000013FEBF4A9  mov         qword ptr [rsp+1E8h],rax  
000000013FEBF4B1  lea         rax,[rsp+1F0h]  
000000013FEBF4B9  mov         qword ptr [rsp+200h],rax  
000000013FEBF4C1  lea         rdx,[rsp+118h]  
000000013FEBF4C9  mov         rcx,qword ptr [rsp+1E8h]  
000000013FEBF4D1  call        eflib::vec3::vec3 (13FEB27C0h)  
000000013FEBF4D6  mov         qword ptr [rsp+300h],rax  
000000013FEBF4DE  lea         rdx,[rsp+0E8h]  
000000013FEBF4E6  mov         rcx,qword ptr [rsp+200h]  
000000013FEBF4EE  call        eflib::vec3::vec3 (13FEB27C0h)  
000000013FEBF4F3  mov         rcx,qword ptr [rsp+300h]  
000000013FEBF4FB  mov         rdx,rcx  
000000013FEBF4FE  mov         rcx,rax  
000000013FEBF501  call        qword ptr [rsp+98h]  
000000013FEBF508  movss       dword ptr [rsp+144h],xmm0  


00000000002C0013  db          38h  
00000000002C0014  movss       xmm4,dword ptr [rsp+68h]  
00000000002C001A  movss       xmm5,dword ptr [rsp+60h]  
00000000002C0020  movss       dword ptr [rsp+20h],xmm5  
00000000002C0026  movss       dword ptr [rsp+28h],xmm4  
00000000002C002C  mov         rax,0F0010h  
00000000002C0036  call        rax  ; It's another function.
00000000002C0038  add         rsp,38h  
00000000002C003C  ret  

And MSDN said if struct is bigger than 64bit, it will save the pointer to rcx
and rdx as arguments. So I don't know what I mistake on it.

Thank you.

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