| ; In this test we check how heuristics for complete unrolling work. We have |
| ; three knobs: |
| ; 1) -unroll-threshold |
| ; 3) -unroll-percent-dynamic-cost-saved-threshold and |
| ; 2) -unroll-dynamic-cost-savings-discount |
| ; |
| ; They control loop-unrolling according to the following rules: |
| ; * If size of unrolled loop exceeds the absoulte threshold, we don't unroll |
| ; this loop under any circumstances. |
| ; * If size of unrolled loop is below the '-unroll-threshold', then we'll |
| ; consider this loop as a very small one, and completely unroll it. |
| ; * If a loop size is between these two tresholds, we only do complete unroll |
| ; it if estimated number of potentially optimized instructions is high (we |
| ; specify the minimal percent of such instructions). |
| |
| ; In this particular test-case, complete unrolling will allow later |
| ; optimizations to remove ~55% of the instructions, the loop body size is 9, |
| ; and unrolled size is 65. |
| |
| ; 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=TEST1 |
| ; 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=TEST2 |
| ; 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=TEST3 |
| |
| ; 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 |
| ; 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 |
| ; 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 |
| |
| ; Check that these work when the unroller has partial unrolling enabled too. |
| ; 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 |
| ; 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 |
| ; 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 |
| |
| ; If the absolute threshold is too low, we should not unroll: |
| ; TEST1: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv |
| |
| ; Otherwise, we should: |
| ; TEST2-NOT: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv |
| |
| ; If we do not boost threshold, the unroll will not happen: |
| ; TEST3: %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv |
| |
| ; And check that we don't crash when we're not allowed to do any analysis. |
| ; RUN: opt < %s -passes=loop-unroll -unroll-max-iteration-count-to-analyze=0 -disable-output |
| ; RUN: opt < %s -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=0 -disable-output |
| target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" |
| |
| @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 |
| |
| define i32 @foo(ptr noalias nocapture readonly %src) { |
| entry: |
| br label %loop |
| |
| loop: ; preds = %loop, %entry |
| %iv = phi i64 [ 0, %entry ], [ %inc, %loop ] |
| %r = phi i32 [ 0, %entry ], [ %add, %loop ] |
| %arrayidx = getelementptr inbounds i32, ptr %src, i64 %iv |
| %src_element = load i32, ptr %arrayidx, align 4 |
| %array_const_idx = getelementptr inbounds [9 x i32], ptr @known_constant, i64 0, i64 %iv |
| %const_array_element = load i32, ptr %array_const_idx, align 4 |
| %mul = mul nsw i32 %src_element, %const_array_element |
| %add = add nsw i32 %mul, %r |
| %inc = add nuw nsw i64 %iv, 1 |
| %exitcond86.i = icmp eq i64 %inc, 9 |
| br i1 %exitcond86.i, label %loop.end, label %loop |
| |
| loop.end: ; preds = %loop |
| %r.lcssa = phi i32 [ %r, %loop ] |
| ret i32 %r.lcssa |
| } |