Source: llvm-toolchain-7 Version: 1:7.0.1~+rc2-7 Severity: grave LLVM violates the i386 baseline by using SSE2, which on this Pentium III machine results in a crash when starting xorg due to an illegal instruction:
[ 112.413] (EE) [ 112.413] (EE) Backtrace: [ 112.414] (EE) 0: /usr/lib/xorg/Xorg (OsLookupColor+0x122) [0x5c4a62] [ 112.416] (EE) 1: linux-gate.so.1 (?+0x0) [0xb7fc5d68] [ 112.420] (EE) 2: /lib/i386-linux-gnu/libLLVM-7.so.1 (_init+0x52eea) [0xae21d898] [ 112.420] (EE) [ 112.421] (EE) Illegal instruction at address 0xae1ca9ae [ 112.421] (EE) Fatal server error: [ 112.421] (EE) Caught signal 4 (Illegal instruction). Server aborting Reverting back to mesa 18.1.9 and thus LLVM 6 fixes the problem. With the LLVM dev tools, the problem can be trivially reproduced: $ llvm-config-7 Illegal instruction $ GDB confirms that it's caused by SSE2: (gdb) x/1i $eip => 0xb4fde9ae: punpcklqdq %xmm1,%xmm2
