https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85525
--- Comment #7 from Tom Ritter <tom at ritter dot vg> --- I'm compiling some AVX code with MinGW+gcc. I'm afraid it's difficult to create a test case, but I think there's an alignment issue here. Registers at crash site: rbp is 0x00 % 20 > 0:000> r > rax=0000000015ce306b rbx=0000000000656930 rcx=000000001f1ba500 > rdx=0000000000000000 rsi=0000000000000000 rdi=0000000000656440 > rip=00000000072656fa rsp=0000000000656bc0 rbp=0000000000657060 > r8=000000001fc0f0a0 r9=0000000000000018 r10=000000001fc0f0a0 > r11=000000001f75bcff r12=0000000000657c90 r13=000000000000000f > r14=0000000000000000 r15=0000000000000000 > iopl=0 nv up ei pl nz na po nc > cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010204 > xul!XRE_GetBootstrap+0x256380a: > 00000000`072656fa c5fd7f45f0 vmovdqa ymmword ptr [rbp-10h],ymm0 > ss:00000000`00657050=17 Disassembly: vmovdqa expects 0x20 alignment but offset by 0x10: 00000000`072356fa c5fd7f45f0 vmovdqa ymmword ptr [rbp-10h],ymm0 I've attached the disassembly. The c++ code is attached and also at: https://searchfox.org/mozilla-central/rev/36dec78aecc40539ecc8d78e91612e38810f963c/gfx/skia/skia/src/opts/SkOpts_hsw.cpp There is a function; convolve_16_pixels that corresponds to xul!XRE_GetBootstrap+0x6676510 in the attached disassembly It was pointed out that 00000000`07235595 48c1e805 shr rax,5 00000000`07235599 48c1e005 shl rax,5 00000000`0723559d 4889c3 mov rbx,rax aligns rbx at the entry to the function, so it can safely do things like vmovdqa ymmword ptr [rbx+3E0h],ymm0 However rbp does not get the same alignment treatment, and operations offset from it may not be correctly aligned.
