On Windows clang produce bad binary for global 4-element `double` array and `__builtin_shufflevector`

[llvmbot]

Bugzilla Link	23528
Version	trunk
OS	Windows NT
Attachments	Visual Studio 2013 access violation with dissam window screenshot;
Reporter	LLVM Bugzilla Contributor

Extended Description

Latest clang 3.7 for Windows (LLVM-3.7.0-r237002-win32) produce bad binary for program:

#include <stdio.h>
#define N 4
typedef double VecTy __attribute__((__vector_size__( sizeof(double) * N)));
double L[] = { 2.5, -0.1, 0.9, 5.1 };

int main(void) {
  VecTy *L_vec = (VecTy*)L;
  VecTy res = __builtin_shufflevector(*L_vec, *L_vec, 1, 2, 3, 0);

  for (int i = 0; i < sizeof(res)/sizeof(res[0]); i++) {
    printf("%f ", res[i]);
  }
}

Build: clang -g VecShuffle.cpp

Actual result, Windows 7 64bit (under Visual Studio):
See attached vs_access_violation.png

Actual result, Windows 7 64bit (under gdb):

>gdb a.exe
(gdb) run
Starting program: C:\workfolder\clang_tests\a.exe
[New Thread 10552.0x323c]
Program received signal SIGSEGV, Segmentation fault.


Expected result: the same on linux(redhat) -
 ./a.out
-0.100000 0.900000 5.100000 2.500000

Note: If you move L[] inside main block, the result on windows will be correct:

C:\workfolder\clang_tests>a.exe
-0.100000 0.900000 5.100000 2.500000

[AaronBallman]

I cannot reproduce this issue as of Clang 20 on Windows (I don't have earlier versions handy to test against), so closing this as completed. If the issue still reproduces for you, feel free to reopen the bug with more details.