#13629: sqrt should use machine instruction on x86_64 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler (NCG) | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Runtime | Test Case: performance bug | numeric/num009 Blocked By: | Blocking: Related Tickets: #13570 | Differential Rev(s): Phab:D3508 Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): For the record, `sqrtf` is the following on my machine, {{{#!asm 0x00007ffff78892c0 <+0>: pxor %xmm1,%xmm1 0x00007ffff78892c4 <+4>: ucomiss %xmm0,%xmm1 0x00007ffff78892c7 <+7>: ja 0x7ffff78892d0 <__sqrtf+16> 0x00007ffff78892c9 <+9>: sqrtss %xmm0,%xmm0 0x00007ffff78892cd <+13>: retq 0x00007ffff78892ce <+14>: xchg %ax,%ax 0x00007ffff78892d0 <+16>: mov 0x2cccf9(%rip),%rax # 0x7ffff7b55fd0 0x00007ffff78892d7 <+23>: cmpl $0xffffffff,(%rax) 0x00007ffff78892da <+26>: je 0x7ffff78892c9 <__sqrtf+9> 0x00007ffff78892dc <+28>: movaps %xmm0,%xmm1 0x00007ffff78892df <+31>: mov $0x7e,%edi 0x00007ffff78892e4 <+36>: jmpq 0x7ffff788ed50 <__kernel_standard_f> }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13629#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler