src/cpu/x86/vm/vm_version_x86.cpp

*** 63,72 ****
--- 63,73 ----
      const uint32_t HS_EFL_ID = 0x200000;
      // Values for when we don't have a CPUID instruction.
      const int      CPU_FAMILY_SHIFT = 8;
      const uint32_t CPU_FAMILY_386 = (3 << CPU_FAMILY_SHIFT);
      const uint32_t CPU_FAMILY_486 = (4 << CPU_FAMILY_SHIFT);
+     bool use_evex = FLAG_IS_DEFAULT(UseAVX) || (UseAVX > 2);
  
      Label detect_486, cpu486, detect_586, std_cpuid1, std_cpuid4;
      Label sef_cpuid, ext_cpuid, ext_cpuid1, ext_cpuid5, ext_cpuid7, done, wrapup;
      Label legacy_setup, save_restore_except, legacy_save_restore, start_simd_check;
  
*** 356,365 ****
--- 357,368 ----
      __ movl(rax, 0xE0);
      __ andl(rax, Address(rbp, in_bytes(VM_Version::xem_xcr0_offset()))); // xcr0 bits sse | ymm
      __ cmpl(rax, 0xE0);
      __ jccb(Assembler::notEqual, legacy_setup); // jump if EVEX is not supported
  
+     // If UseAVX is unitialized or is set by the user to include EVEX
+     if (use_evex) {
        // EVEX setup: run in lowest evex mode
        VM_Version::set_evex_cpuFeatures(); // Enable temporary to pass asserts
        UseAVX = 3;
        UseSSE = 2;
  #ifdef _WINDOWS
*** 386,395 ****
--- 389,399 ----
        __ evmovdqul(xmm8, xmm0, Assembler::AVX_512bit);
        __ evmovdqul(xmm31, xmm0, Assembler::AVX_512bit);
  #endif
        VM_Version::clean_cpuFeatures();
        __ jmp(save_restore_except);
+     }
  
      __ bind(legacy_setup);
      // AVX setup
      VM_Version::set_avx_cpuFeatures(); // Enable temporary to pass asserts
      UseAVX = 1;
*** 439,448 ****
--- 443,454 ----
      __ movl(rax, 0xE0);
      __ andl(rax, Address(rbp, in_bytes(VM_Version::xem_xcr0_offset()))); // xcr0 bits sse | ymm
      __ cmpl(rax, 0xE0);
      __ jccb(Assembler::notEqual, legacy_save_restore);
  
+     // If UseAVX is unitialized or is set by the user to include EVEX
+     if (use_evex) {
        // EVEX check: run in lowest evex mode
        VM_Version::set_evex_cpuFeatures(); // Enable temporary to pass asserts
        UseAVX = 3;
        UseSSE = 2;
        __ lea(rsi, Address(rbp, in_bytes(VM_Version::zmm_save_offset())));
*** 465,474 ****
--- 471,481 ----
  #endif // _WINDOWS
        VM_Version::clean_cpuFeatures();
        UseAVX = saved_useavx;
        UseSSE = saved_usesse;
        __ jmp(wrapup);
+     }
  
      __ bind(legacy_save_restore);
      // AVX check
      VM_Version::set_avx_cpuFeatures(); // Enable temporary to pass asserts
      UseAVX = 1;