Index: lib/Transforms/Scalar/LoopUnswitch.cpp =================================================================== --- lib/Transforms/Scalar/LoopUnswitch.cpp +++ lib/Transforms/Scalar/LoopUnswitch.cpp @@ -708,10 +708,8 @@ // unswitch on it if we desire. Value *LoopCond = FindLIVLoopCondition(BI->getCondition(), currentLoop, Changed).first; - if (!LoopCond || EqualityPropUnSafe(*LoopCond)) - continue; - - if (UnswitchIfProfitable(LoopCond, ConstantInt::getTrue(Context), TI)) { + if (LoopCond && !EqualityPropUnSafe(*LoopCond) && + UnswitchIfProfitable(LoopCond, ConstantInt::getTrue(Context), TI)) { ++NumBranches; return true; } Index: test/Transforms/LoopUnswitch/unswitch-select.ll =================================================================== --- test/Transforms/LoopUnswitch/unswitch-select.ll +++ test/Transforms/LoopUnswitch/unswitch-select.ll @@ -0,0 +1,26 @@ +; REQUIRES: asserts +; RUN: opt < %s -loop-unswitch -disable-output -stats 2>&1| FileCheck %s + +; Check the select statement in the loop will be unswitched. +; CHECK: 1 loop-unswitch - Number of selects unswitched +define i32 @test(i1 zeroext %x, i32 %a) local_unnamed_addr #0 { +entry: + br label %while.cond + +while.cond: ; preds = %while.body, %entry + %i.0 = phi i32 [ 0, %entry ], [ %inc, %while.body ] + %s.0 = phi i32 [ %a, %entry ], [ %add, %while.body ] + %cmp = icmp slt i32 %i.0, 10000 + br i1 %cmp, label %while.body, label %while.end + +while.body: ; preds = %while.cond + %cond = select i1 %x, i32 %a, i32 %i.0 + %add = add nsw i32 %s.0, %cond + %inc = add nsw i32 %i.0, 1 + br label %while.cond + +while.end: ; preds = %while.cond + %s.0.lcssa = phi i32 [ %s.0, %while.cond ] + ret i32 %s.0.lcssa +} +