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[InstCombine] PR35354: Convert store(bitcast, load bitcast (select (C…
…ond, &V1, &V2)) --> store (, load (select(Cond, load &V1, load &V2))) Summary: If we have the code like this: ``` float a, b; a = std::max(a ,b); ``` it is converted into something like this: ``` %call = call dereferenceable(4) float* @_ZSt3maxIfERKT_S2_S2_(float* nonnull dereferenceable(4) %a.addr, float* nonnull dereferenceable(4) %b.addr) %1 = bitcast float* %call to i32* %2 = load i32, i32* %1, align 4 %3 = bitcast float* %a.addr to i32* store i32 %2, i32* %3, align 4 ``` After inlinning this code is converted to the next: ``` %1 = load float, float* %a.addr %2 = load float, float* %b.addr %cmp.i = fcmp fast olt float %1, %2 %__b.__a.i = select i1 %cmp.i, float* %a.addr, float* %b.addr %3 = bitcast float* %__b.__a.i to i32* %4 = load i32, i32* %3, align 4 %5 = bitcast float* %arrayidx to i32* store i32 %4, i32* %5, align 4 ``` This pattern is not recognized as minmax pattern. Patch solves this problem by converting sequence ``` store (bitcast, (load bitcast (select ((cmp V1, V2), &V1, &V2)))) ``` to a sequence ``` store (,load (select((cmp V1, V2), &V1, &V2))) ``` After this the code is recognized as minmax pattern. Reviewers: RKSimon, spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D40304 llvm-svn: 320157
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