xref: /llvm-project/llvm/test/Transforms/SimpleLoopUnswitch/exponential-nontrivial-unswitch-nested.ll (revision 2f79f5438cd6f4fa0fdc32458911c2d163f917c0)
1;
2; There should be just a single copy of each loop when strictest mutiplier
3; candidates formula (unscaled candidates == 0) is enforced:
4
5; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
6; RUN:     -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=1 \
7; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
8;
9; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
10; RUN:     -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=16 \
11; RUN: -passes='loop(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
12;
13; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
14; RUN:     -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=1 \
15; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
16;
17; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
18; RUN:     -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=16 \
19; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
20;
21; When we relax the candidates part of a multiplier formula
22; (unscaled candidates == 4) we start getting  some unswitches,
23; which leads to siblings multiplier kicking in.
24;
25; The tests below also run licm, because it is needed to hoist out
26; loop-invariant freeze instructions, which otherwise may block further
27; unswitching.
28;
29; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
30; RUN:     -unswitch-num-initial-unscaled-candidates=4 -unswitch-siblings-toplevel-div=1 \
31; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
32; RUN:     sort -b -k 1 | FileCheck %s --check-prefixes=LOOP-UNSCALE4-DIV1
33;
34; NB: sort -b is essential here and below, otherwise blanks might lead to different
35; order depending on locale.
36;
37; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
38; RUN:     -unswitch-num-initial-unscaled-candidates=4 -unswitch-siblings-toplevel-div=2 \
39; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
40; RUN:     sort -b -k 1 | FileCheck %s --check-prefixes=LOOP-UNSCALE4-DIV2
41;
42; Get
43;    2^(num conds) == 2^5 = 32
44; loop nests when cost multiplier is disabled:
45;
46; RUN: opt < %s -enable-unswitch-cost-multiplier=false \
47; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
48; RUN:	   sort -b -k 1 | FileCheck %s --check-prefixes=LOOP32
49;
50; Single loop nest, not unswitched
51; LOOP1:     Loop at depth 1 containing:
52; LOOP1:     Loop at depth 2 containing:
53; LOOP1:     Loop at depth 3 containing:
54; LOOP1-NOT: Loop at depth {{[0-9]+}} containing:
55;
56; Half unswitched loop nests, with unscaled4 and div1 it gets less depth1 loops unswitched
57; since they have more cost.
58; LOOP-UNSCALE4-DIV1-COUNT-6: Loop at depth 1 containing:
59; LOOP-UNSCALE4-DIV1-COUNT-19: Loop at depth 2 containing:
60; LOOP-UNSCALE4-DIV1-COUNT-29: Loop at depth 3 containing:
61; LOOP-UNSCALE4-DIV1-NOT:      Loop at depth {{[0-9]+}} containing:
62;
63; Half unswitched loop nests, with unscaled4 and div2 it gets more depth1 loops unswitched
64; as div2 kicks in.
65; LOOP-UNSCALE4-DIV2-COUNT-11: Loop at depth 1 containing:
66; LOOP-UNSCALE4-DIV2-COUNT-22: Loop at depth 2 containing:
67; LOOP-UNSCALE4-DIV2-COUNT-29: Loop at depth 3 containing:
68; LOOP-UNSCALE4-DIV2-NOT:      Loop at depth {{[0-9]+}} containing:
69;
70; 32 loop nests, fully unswitched
71; LOOP32-COUNT-32: Loop at depth 1 containing:
72; LOOP32-COUNT-32: Loop at depth 2 containing:
73; LOOP32-COUNT-32: Loop at depth 3 containing:
74; LOOP32-NOT:      Loop at depth {{[0-9]+}} containing:
75
76declare void @bar()
77
78define void @loop_nested3_conds5(ptr %addr, i1 %c1, i1 %c2, i1 %c3, i1 %c4, i1 %c5) {
79entry:
80  %addr2 = getelementptr i32, ptr %addr, i64 1
81  %addr3 = getelementptr i32, ptr %addr, i64 2
82  br label %outer
83outer:
84  %iv1 = phi i32 [0, %entry], [%iv1.next, %outer_latch]
85  %iv1.next = add i32 %iv1, 1
86  ;; skip nontrivial unswitch
87  call void @bar()
88  br label %middle
89middle:
90  %iv2 = phi i32 [0, %outer], [%iv2.next, %middle_latch]
91  %iv2.next = add i32 %iv2, 1
92  ;; skip nontrivial unswitch
93  call void @bar()
94  br label %loop
95loop:
96  %iv3 = phi i32 [0, %middle], [%iv3.next, %loop_latch]
97  %iv3.next = add i32 %iv3, 1
98  ;; skip nontrivial unswitch
99  call void @bar()
100  br i1 %c1, label %loop_next1_left, label %loop_next1_right
101loop_next1_left:
102  br label %loop_next1
103loop_next1_right:
104  br label %loop_next1
105
106loop_next1:
107  br i1 %c2, label %loop_next2_left, label %loop_next2_right
108loop_next2_left:
109  br label %loop_next2
110loop_next2_right:
111  br label %loop_next2
112
113loop_next2:
114  br i1 %c3, label %loop_next3_left, label %loop_next3_right
115loop_next3_left:
116  br label %loop_next3
117loop_next3_right:
118  br label %loop_next3
119
120loop_next3:
121  br i1 %c4, label %loop_next4_left, label %loop_next4_right
122loop_next4_left:
123  br label %loop_next4
124loop_next4_right:
125  br label %loop_next4
126
127loop_next4:
128  br i1 %c5, label %loop_latch_left, label %loop_latch_right
129loop_latch_left:
130  br label %loop_latch
131loop_latch_right:
132  br label %loop_latch
133
134loop_latch:
135  store volatile i32 0, ptr %addr
136  %test_loop = icmp slt i32 %iv3, 50
137  br i1 %test_loop, label %loop, label %middle_latch
138middle_latch:
139  store volatile i32 0, ptr %addr2
140  %test_middle = icmp slt i32 %iv2, 50
141  br i1 %test_middle, label %middle, label %outer_latch
142outer_latch:
143  store volatile i32 0, ptr %addr3
144  %test_outer = icmp slt i32 %iv1, 50
145  br i1 %test_outer, label %outer, label %exit
146exit:
147  ret void
148}
149