Well, this wasn't as trivial as I had hoped. With the latest version of Xcode -- 7.3.1 (7D1014) -- it appears there is some bad code being generated; specifically a movaps instruction with a pointer that isn't 16-byte aligned. This is different from what the buildbot [1] -- with Xcode 7.2 (7C68) -- generated. _MPID_Request_create: [....] 000000000012bcaf movq $0x0, 0x1c8(%rax) 000000000012bcba movq $0x0, 0x1c0(%rax) 000000000012bcc5 movq $0x0, 0x1b8(%rax) 000000000012bcd0 xorps %xmm0, %xmm0 000000000012bcd3 movaps %xmm0, 0x230(%rax) <<< CRASH 000000000012bcda movq $0x0, 0x240(%rax) 000000000012bce5 movl $0x2c000000, 0x210(%rax) ## imm = 0x2C000000 000000000012bcef popq %rbp At crash, %rax == 0x000000010af39048 + 230 = 0x10AF39258 (not 16-byte aligned). Fall down go boom. %rax is a pointer to a new handle object returned from MPIU_Handle_obj_alloc() if I'm reading things correctly. vs: _MPID_Request_create: [...] 000000000011d3db movq $0x0, 0x1c0(%rax) 000000000011d3e6 movq $0x0, 0x1b8(%rax) 000000000011d3f1 movq $0x0, 0x240(%rax) 000000000011d3fc movq $0x0, 0x238(%rax) 000000000011d407 movq $0x0, 0x230(%rax) 000000000011d412 movl $0x2c000000, 0x210(%rax) ## imm = 0x2C000000 000000000011d41c popq %rbp I'm not ready to dig into this further tonight, but wanted to post it up here for Ben and awareness. I don't know if the actual error is a "compiler error" in the emitted movaps instruction, or if a pointer that was advertised (in the code) to be 16-byte aligned wasn't for some reason... (If I use the builedbot package, the test example works; if I use the local build, I get a crash just like Ben.) If someone on the MPICH team has the latest XCode and could verify or refute, that would be helpful. We're at n=2/2 so far... - Eric [1] http://packages.macports.org/mpich-default/mpich-default-3.2_0+gcc5.darwin_1... On Thu, May 26, 2016 at 8:53 AM, Eric A. Borisch <[email protected]> wrote:

On Thu, May 26, 2016 at 7:21 AM, Ben Whale <[email protected]> wrote:

...

Since I really expected this code to work I suspect that I’ve installed mpich incorrectly.

I’m on OSX 10.11.4 and installed mpich using the command sudo port install mpich

Ben,

Output of "which mpicc", "which mpiexec", and "otool -L minimal_working_example"? I'm hopeful there will be something interesting from one of those; we can likely take this off-list unless others would like to chime in.

- Eric (I maintain the MacPorts mpich ports.)

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