[PATCH] D153472: AMDGPU: Correctly expand f64 sqrt intrinsic

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/test/CodeGen/AMDGPU/fsqrt.f64.ll:44
-; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; GCN-NEXT:    v_sqrt_f64_e64 v[0:1], -|v[0:1]|
-; GCN-NEXT:    s_setpc_b64 s[30:31]
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Pierre-vh wrote:
> I think I need some context, why is `v_sqrt_f64` so bad that this expansion is preferred? Accuracy/semantics?
It's nowhere near accurate enough, I don't really know what the point of the instruction is. The raw instruction definitely just fails OpenCL conformance


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  https://reviews.llvm.org/D153472/new/

https://reviews.llvm.org/D153472