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1; In this test we check how heuristics for complete unrolling work. We have2; three knobs:3; 1) -unroll-threshold4; 3) -unroll-percent-dynamic-cost-saved-threshold and5; 2) -unroll-dynamic-cost-savings-discount6;7; They control loop-unrolling according to the following rules:8; * If size of unrolled loop exceeds the absoulte threshold, we don't unroll9; this loop under any circumstances.10; * If size of unrolled loop is below the '-unroll-threshold', then we'll11; consider this loop as a very small one, and completely unroll it.12; * If a loop size is between these two tresholds, we only do complete unroll13; it if estimated number of potentially optimized instructions is high (we14; specify the minimal percent of such instructions).15 16; In this particular test-case, complete unrolling will allow later17; optimizations to remove ~55% of the instructions, the loop body size is 9,18; and unrolled size is 65.19 20; RUN: opt < %s -S -passes=loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST121; RUN: opt < %s -S -passes=loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=200 | FileCheck %s -check-prefix=TEST222; RUN: opt < %s -S -passes=loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST323 24; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST125; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=200 | FileCheck %s -check-prefix=TEST226; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST327 28; Check that these work when the unroller has partial unrolling enabled too.29; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop-unroll' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST130; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop-unroll' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=200 | FileCheck %s -check-prefix=TEST231; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop-unroll' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST332 33; If the absolute threshold is too low, we should not unroll:34; TEST1: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv35 36; Otherwise, we should:37; TEST2-NOT: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv38 39; If we do not boost threshold, the unroll will not happen:40; TEST3: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv41 42; And check that we don't crash when we're not allowed to do any analysis.43; RUN: opt < %s -passes=loop-unroll -unroll-max-iteration-count-to-analyze=0 -disable-output44; RUN: opt < %s -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=0 -disable-output45target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"46 47@known_constant = internal unnamed_addr constant [9 x i32] [i32 0, i32 -1, i32 0, i32 -1, i32 5, i32 -1, i32 0, i32 -1, i32 0], align 1648 49define i32 @foo(ptr noalias nocapture readonly %src) {50entry:51 br label %loop52 53loop: ; preds = %loop, %entry54 %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]55 %r = phi i32 [ 0, %entry ], [ %add, %loop ]56 %arrayidx = getelementptr inbounds i32, ptr %src, i64 %iv57 %src_element = load i32, ptr %arrayidx, align 458 %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv59 %const_array_element = load i32, ptr %array_const_idx, align 460 %mul = mul nsw i32 %src_element, %const_array_element61 %add = add nsw i32 %mul, %r62 %inc = add nuw nsw i64 %iv, 163 %exitcond86.i = icmp eq i64 %inc, 964 br i1 %exitcond86.i, label %loop.end, label %loop65 66loop.end: ; preds = %loop67 %r.lcssa = phi i32 [ %r, %loop ]68 ret i32 %r.lcssa69}70