search for: cmovbe

...rlq mm3, 32 ; mm3 = 0:total_error_1 - movd ebx, mm0 ; ebx = total_error_0 movd ecx, mm3 ; ecx = total_error_1 - emms - mov eax, ebx ; eax = total_error_0 - cmp ecx, ebx + + xor ebx, ebx + xor ebp, ebp + inc ebx + cmp ecx, eax cmovb eax, ecx ; eax = min(total_error_0, total_error_1) + cmovbe ebp, ebx + inc ebx cmp edx, eax cmovb eax, edx ; eax = min(total_error_0, total_error_1, total_error_2) + cmovbe ebp, ebx + inc ebx cmp esi, eax cmovb eax, esi ; eax = min(total_error_0, total_error_1, total_error_2, total_error_3) + cmovbe ebp, ebx + inc ebx cmp edi, eax cmovb eax,...

> On Jan 22, 2015, at 1:22 PM, Fiona Glaser <fglaser at apple.com> wrote: > > According to Agner’s docs, many CPUs have slower BT than TEST; Haswell has only 0.5 inverse throughput as opposed to 0.25, Atom has 1 instead of 0.5, and Silvermont can’t even dual-issue BT (it locks both ALUs). So while BT does seem have a shorter instruction encoding than TEST for TEST reg, imm32 where

Changing the list from cfe-dev to llvm-dev > On 20 Apr 2017, at 4:52 AM, Michael Clark <michaeljclark at mac.com> wrote: > > I’m getting close. I think it may be an issue with an individual intrinsic. I’m looking for the X86 lowering of Instruction::FPToUI. > > I found a comment around the rationale for using a conditional move versus a branch. I believe the predicate logic

...<chris.sears at gmail.com> wrote: > > I think the partial update issue isn't really valid concern, Agner Fogg, p 142. I don't think LLVM is going to emit this fragment. > > ; Example 10.7. Partial register access > bt eax,2 ; modifies carry flag but not zero flag > cmovbe eax,ebx ; reads both carry flag and zero flag > > In cases like this, you may consider whether it is a programming error or a deliberate testing of two different conditions with a single instruction. > _______________________________________________ > LLVM Developers mailing list >...

Hi everyone! I've faced a strange problem after updating to Windows 8 Consumer Preview recently. It seems that LLVM inserts 4 calls to the same function at the start of generated code. The function's disassembly (taken from nearby computer with Windows 7) is: 00000000773A0DD0 sub rsp,10h 00000000773A0DD4 mov qword ptr [rsp],r10 00000000773A0DD8 mov qword ptr

Hi all, Some background: I'm working on a project to replace a custom VM with various components of llvm. We have everything running just peachy keen with one recent exception, one of our executables crashes when attempting run a JIT'd function. We have llvm building and running on 64 bit Windows and Linux, using Visual Studio 2008 on Windows and gcc on Linux, and we have the llvm

> This seems like it was done for perf reason (mispredict). Conditional-to-cmov transformation should keep > from introducing additional observable side-effects, and it's clear that whatever did this did not account > for floating point exception. That’s a very reasonable statement, but I’m not sure it corresponds to the way we have typically approached this sort of problem. In

Hi all, me again! Well, after much hacking of code and thinking and frustration, I finally figured out what I was doing wrong. It turns out my initial attempts at using various gflags settings were causing VirtualAlloc to return GIANT addresses. In particular, the Application Verifier flag ( -vrf ), seems to cause VirtualAlloc to do what looks like top-down allocations and then llvm happily

I think it’s generally true that whenever branches can reliably be predicted branching is faster than a cmov that involves speculative execution, and I would guess that your assessment regarding looping on input values is probably correct. I believe the code that actually creates most of the transformation you’re interested in here is in SelectionDAGLegalize::ExpandNode() in LegalizeDAG.cpp. The