Since the revision, 434.zeusmp and other SPEC benchmarks do fail with -march=native -Ofast on AMD znver1 and Intel skylake.

I isolated that the affected source file is tranx3.f, where I can see a couple of assembly changes like:

Before:

	vmulsd	gridcomr_+44688(,%rax,8), %xmm2, %xmm2
	vaddsd	%xmm2, %xmm0, %xmm1
	vmulsd	%xmm2, %xmm0, %xmm0
	vxorpd	%xmm2, %xmm2, %xmm2
	vmaxsd	%xmm2, %xmm0, %xmm0
	vmovsd	%xmm1, %xmm1, %xmm2
	vandpd	.LC1(%rip), %xmm2, %xmm2
	vxorpd	%xmm0, %xmm2, %xmm2
	vandpd	.LC2(%rip), %xmm1, %xmm0
	vmovsd	.LC3(%rip), %xmm1
	vmaxsd	%xmm1, %xmm0, %xmm0
	vdivsd	%xmm0, %xmm2, %xmm0
	vmovsd	%xmm0, 856(%rsp,%rbx,8)
.L102:

After:

	vmulsd	gridcomr_+44688(,%rbx,8), %xmm0, %xmm0
	vsubsd	%xmm2, %xmm1, %xmm2
	vmulsd	gridcomr_+44688(,%rax,8), %xmm2, %xmm2
	vaddsd	%xmm2, %xmm0, %xmm1
	vandpd	.LC1(%rip), %xmm1, %xmm1
	vmulsd	%xmm2, %xmm0, %xmm0
	vxorpd	%xmm2, %xmm2, %xmm2
	vmaxsd	%xmm2, %xmm0, %xmm0
	vmovsd	.LC3(%rip), %xmm2
	vxorpd	%xmm0, %xmm1, %xmm0
	vandpd	.LC2(%rip), %xmm1, %xmm1
	vmaxsd	%xmm2, %xmm1, %xmm1
	vdivsd	%xmm1, %xmm0, %xmm0
	vmovsd	%xmm0, 856(%rsp,%rbx,8)
.L102:

@H.J. Can you please take a look? It's not easy to reproduce a smaller test-case ..