1 ; In this test we check how heuristics for complete unrolling work. We have
4 ; 2) -unroll-absolute-threshold and
5 ; 3) -unroll-percent-of-optimized-for-complete-unroll
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).
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.
20 ; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-absolute-threshold=10 -unroll-threshold=10 -unroll-percent-of-optimized-for-complete-unroll=30 | FileCheck %s -check-prefix=TEST1
21 ; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-absolute-threshold=100 -unroll-threshold=10 -unroll-percent-of-optimized-for-complete-unroll=30 | FileCheck %s -check-prefix=TEST2
22 ; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-absolute-threshold=100 -unroll-threshold=10 -unroll-percent-of-optimized-for-complete-unroll=80 | FileCheck %s -check-prefix=TEST3
23 ; RUN: opt < %s -S -loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-absolute-threshold=100 -unroll-threshold=100 -unroll-percent-of-optimized-for-complete-unroll=80 | FileCheck %s -check-prefix=TEST4
25 ; If the absolute threshold is too low, or if we can't optimize away requested
26 ; percent of instructions, we shouldn't unroll:
27 ; TEST1: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv
28 ; TEST3: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv
30 ; Otherwise, we should:
31 ; TEST2-NOT: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv
33 ; Also, we should unroll if the 'unroll-threshold' is big enough:
34 ; TEST4-NOT: %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv
36 ; And check that we don't crash when we're not allowed to do any analysis.
37 ; RUN: opt < %s -loop-unroll -unroll-max-iteration-count-to-analyze=0 -disable-output
38 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
40 @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
42 define i32 @foo(i32* noalias nocapture readonly %src) {
46 loop: ; preds = %loop, %entry
47 %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]
48 %r = phi i32 [ 0, %entry ], [ %add, %loop ]
49 %arrayidx = getelementptr inbounds i32, i32* %src, i64 %iv
50 %src_element = load i32, i32* %arrayidx, align 4
51 %array_const_idx = getelementptr inbounds [9 x i32], [9 x i32]* @known_constant, i64 0, i64 %iv
52 %const_array_element = load i32, i32* %array_const_idx, align 4
53 %mul = mul nsw i32 %src_element, %const_array_element
54 %add = add nsw i32 %mul, %r
55 %inc = add nuw nsw i64 %iv, 1
56 %exitcond86.i = icmp eq i64 %inc, 9
57 br i1 %exitcond86.i, label %loop.end, label %loop
59 loop.end: ; preds = %loop
60 %r.lcssa = phi i32 [ %r, %loop ]