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This commit makes LLVM not estimate branch probabilities when doing a single bit bitmask tests. The code that originally made me discover this is: if ((a & 0x1) == 0x1) { .. } In this case we don't actually have any branch probability information and should not assume to have any. LLVM transforms this into: %and = and i32 %a, 1 %tobool = icmp eq i32 %and, 0 So, in this case, the result of a bitwise and is compared against 0, but nevertheless, we should not assume to have probability information. CodeGen/ARM/2013-10-11-select-stalls.ll started failing because the changed probabilities changed the results of ARMBaseInstrInfo::isProfitableToIfCvt() and led to an Ifcvt of the diamond in the test. AFAICT, the test was never meant to test this and thus changing the test input slightly to not change the probabilities seems like the best way to preserve the meaning of the test. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234979 91177308-0d34-0410-b5e6-96231b3b80d8 |
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basic.ll | ||
loop.ll | ||
noreturn.ll | ||
pr18705.ll |