1; In this test we check how heuristics for complete unrolling work. We have 2; three knobs: 3; 1) -unroll-threshold 4; 3) -unroll-percent-dynamic-cost-saved-threshold and 5; 2) -unroll-dynamic-cost-savings-discount 6; 7; They control loop-unrolling according to the following rules: 8; * If size of unrolled loop exceeds the absoulte threshold, we don't unroll 9; this loop under any circumstances. 10; * If size of unrolled loop is below the '-unroll-threshold', then we'll 11; 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 unroll 13; it if estimated number of potentially optimized instructions is high (we 14; specify the minimal percent of such instructions). 15 16; In this particular test-case, complete unrolling will allow later 17; 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 -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST1 21; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=200 | FileCheck %s -check-prefix=TEST2 22; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=20 -unroll-max-percent-threshold-boost=100 | FileCheck %s -check-prefix=TEST3 23 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=TEST1 25; 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=TEST2 26; 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=TEST3 27 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=TEST1 30; 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=TEST2 31; 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=TEST3 32 33; If the absolute threshold is too low, we should not unroll: 34; TEST1: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv 35 36; Otherwise, we should: 37; TEST2-NOT: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv 38 39; If we do not boost threshold, the unroll will not happen: 40; TEST3: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv 41 42; And check that we don't crash when we're not allowed to do any analysis. 43; RUN: opt < %s -loop-unroll -unroll-max-iteration-count-to-analyze=0 -disable-output 44; RUN: opt < %s -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=0 -disable-output 45target 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 16 48 49define i32 @foo(i32* noalias nocapture readonly %src) { 50entry: 51 br label %loop 52 53loop: ; preds = %loop, %entry 54 %iv = phi i64 [ 0, %entry ], [ %inc, %loop ] 55 %r = phi i32 [ 0, %entry ], [ %add, %loop ] 56 %arrayidx = getelementptr inbounds i32, i32* %src, i64 %iv 57 %src_element = load i32, i32* %arrayidx, align 4 58 %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv 59 %const_array_element = load i32, i32* %array_const_idx, align 4 60 %mul = mul nsw i32 %src_element, %const_array_element 61 %add = add nsw i32 %mul, %r 62 %inc = add nuw nsw i64 %iv, 1 63 %exitcond86.i = icmp eq i64 %inc, 9 64 br i1 %exitcond86.i, label %loop.end, label %loop 65 66loop.end: ; preds = %loop 67 %r.lcssa = phi i32 [ %r, %loop ] 68 ret i32 %r.lcssa 69} 70