Skip to content

Commit 3cbdfe4

Browse files
fhahnfhahn
committed
[SCEV] Add additional max BTC tests with loop guards.
1 parent 024979b commit 3cbdfe4

File tree

1 file changed

+244
-2
lines changed

1 file changed

+244
-2
lines changed

‎llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll

Lines changed: 244 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -24,12 +24,189 @@ exit:
2424
ret void
2525
}
2626

27+
define void @test_guard_less_than_16_branches_flipped(i32* nocapture %a, i64 %i) {
28+
; CHECK-LABEL: Determining loop execution counts for: @test_guard_less_than_16_branches_flipped
29+
; CHECK-NEXT: Loop %loop: backedge-taken count is (15 + (-1 * %i))
30+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
31+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (15 + (-1 * %i))
32+
;
33+
entry:
34+
%cmp3 = icmp ult i64 %i, 16
35+
br i1 %cmp3, label %exit, label %loop
36+
37+
loop:
38+
%iv = phi i64 [ %iv.next, %loop ], [ %i, %entry ]
39+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
40+
store i32 1, i32* %idx, align 4
41+
%iv.next = add nuw nsw i64 %iv, 1
42+
%exitcond = icmp eq i64 %iv.next, 16
43+
br i1 %exitcond, label %exit, label %loop
44+
45+
exit:
46+
ret void
47+
}
48+
49+
define void @test_guard_uge_16_branches_flipped(i32* nocapture %a, i64 %i) {
50+
; CHECK-LABEL: Determining loop execution counts for: @test_guard_uge_16_branches_flipped
51+
; CHECK-NEXT: Loop %loop: backedge-taken count is (15 + (-1 * %i))
52+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
53+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (15 + (-1 * %i))
54+
;
55+
entry:
56+
%cmp3 = icmp uge i64 %i, 16
57+
br i1 %cmp3, label %exit, label %loop
58+
59+
loop:
60+
%iv = phi i64 [ %iv.next, %loop ], [ %i, %entry ]
61+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
62+
store i32 1, i32* %idx, align 4
63+
%iv.next = add nuw nsw i64 %iv, 1
64+
%exitcond = icmp eq i64 %iv.next, 16
65+
br i1 %exitcond, label %exit, label %loop
66+
67+
exit:
68+
ret void
69+
}
70+
71+
define void @test_multiple_const_guards_order1(i32* nocapture %a, i64 %i) {
72+
; CHECK-LABEL: @test_multiple_const_guards_order1
73+
; CHECK: Loop %loop: backedge-taken count is %i
74+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
75+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
76+
;
77+
entry:
78+
%c.1 = icmp ult i64 %i, 16
79+
br i1 %c.1, label %guardbb, label %exit
80+
81+
guardbb:
82+
%c.2 = icmp ult i64 %i, 10
83+
br i1 %c.2, label %loop, label %exit
84+
85+
loop:
86+
%iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
87+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
88+
store i32 1, i32* %idx, align 4
89+
%iv.next = add nuw nsw i64 %iv, 1
90+
%exitcond = icmp eq i64 %iv, %i
91+
br i1 %exitcond, label %exit, label %loop
92+
93+
exit:
94+
ret void
95+
}
96+
97+
define void @test_multiple_const_guards_order2(i32* nocapture %a, i64 %i) {
98+
; CHECK-LABEL: @test_multiple_const_guards_order2
99+
; CHECK: Loop %loop: backedge-taken count is %i
100+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
101+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
102+
;
103+
entry:
104+
%c.1 = icmp ult i64 %i, 10
105+
br i1 %c.1, label %guardbb, label %exit
106+
107+
guardbb:
108+
%c.2 = icmp ult i64 %i, 16
109+
br i1 %c.2, label %loop, label %exit
110+
111+
loop:
112+
%iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
113+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
114+
store i32 1, i32* %idx, align 4
115+
%iv.next = add nuw nsw i64 %iv, 1
116+
%exitcond = icmp eq i64 %iv, %i
117+
br i1 %exitcond, label %exit, label %loop
118+
119+
exit:
120+
ret void
121+
}
122+
123+
; TODO: Currently we miss getting the tightest max backedge-taken count (11).
124+
define void @test_multiple_var_guards_order1(i32* nocapture %a, i64 %i, i64 %N) {
125+
; CHECK-LABEL: @test_multiple_var_guards_order1
126+
; CHECK: Loop %loop: backedge-taken count is %i
127+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
128+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
129+
;
130+
entry:
131+
%c.1 = icmp ult i64 %N, 12
132+
br i1 %c.1, label %guardbb, label %exit
133+
134+
guardbb:
135+
%c.2 = icmp ult i64 %i, %N
136+
br i1 %c.2, label %loop, label %exit
137+
138+
loop:
139+
%iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
140+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
141+
store i32 1, i32* %idx, align 4
142+
%iv.next = add nuw nsw i64 %iv, 1
143+
%exitcond = icmp eq i64 %iv, %i
144+
br i1 %exitcond, label %exit, label %loop
145+
146+
exit:
147+
ret void
148+
}
149+
150+
; TODO: Currently we miss getting the tightest max backedge-taken count (11).
151+
define void @test_multiple_var_guards_order2(i32* nocapture %a, i64 %i, i64 %N) {
152+
; CHECK-LABEL: Determining loop execution counts for: @test_multiple_var_guards_order2
153+
; CHECK-NEXT: Loop %loop: backedge-taken count is %i
154+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
155+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
156+
;
157+
entry:
158+
%c.1 = icmp ult i64 %i, %N
159+
br i1 %c.1, label %guardbb, label %exit
160+
161+
guardbb:
162+
%c.2 = icmp ult i64 %N, 12
163+
br i1 %c.2, label %loop, label %exit
164+
165+
loop:
166+
%iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
167+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
168+
store i32 1, i32* %idx, align 4
169+
%iv.next = add nuw nsw i64 %iv, 1
170+
%exitcond = icmp eq i64 %iv, %i
171+
br i1 %exitcond, label %exit, label %loop
172+
173+
exit:
174+
ret void
175+
}
176+
177+
; The guards here reference each other in a cycle.
178+
define void @test_multiple_var_guards_cycle(i32* nocapture %a, i64 %i, i64 %N) {
179+
; CHECK-LABEL: Determining loop execution counts for: @test_multiple_var_guards_cycle
180+
; CHECK-NEXT: Loop %loop: backedge-taken count is %N
181+
; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
182+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %N
183+
;
184+
entry:
185+
%c.1 = icmp ult i64 %N, %i
186+
br i1 %c.1, label %guardbb, label %exit
187+
188+
guardbb:
189+
%c.2 = icmp ult i64 %i, %N
190+
br i1 %c.2, label %loop, label %exit
191+
192+
loop:
193+
%iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
194+
%idx = getelementptr inbounds i32, i32* %a, i64 %iv
195+
store i32 1, i32* %idx, align 4
196+
%iv.next = add nuw nsw i64 %iv, 1
197+
%exitcond = icmp eq i64 %iv, %N
198+
br i1 %exitcond, label %exit, label %loop
199+
200+
exit:
201+
ret void
202+
}
203+
27204
; Test case for PR47247. Both the guard condition and the assume limit the
28205
; max backedge-taken count.
29206

30207
define void @test_guard_and_assume(i32* nocapture readonly %data, i64 %count) {
31-
; CHECK-LABEL: Determining loop execution counts for: @test_guard_and_assume
32-
; CHECK-NEXT: Loop %loop: backedge-taken count is (-1 + %count)
208+
; CHECK-LABEL: @test_guard_and_assume
209+
; CHECK: Loop %loop: backedge-taken count is (-1 + %count)
33210
; CHECK-NEXT: Loop %loop: max backedge-taken count is -2
34211
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (-1 + %count)
35212
;
@@ -53,3 +230,68 @@ exit:
53230

54231
; Function Attrs: nounwind willreturn
55232
declare void @llvm.assume(i1 noundef)
233+
234+
define void @guard_pessimizes_analysis(i1 %c, i32 %N) {
235+
; CHECK-LABEL: @guard_pessimizes_analysis
236+
; CHECK: Loop %loop: backedge-taken count is (9 + (-1 * %init)<nsw>)<nsw>
237+
; CHECK-NEXT: Loop %loop: max backedge-taken count is 7
238+
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (9 + (-1 * %init)<nsw>)<nsw>
239+
;
240+
entry:
241+
br i1 %c, label %bb1, label %guard
242+
243+
bb1:
244+
br label %guard
245+
246+
guard:
247+
%init = phi i32 [ 2, %entry ], [ 3, %bb1 ]
248+
%c.1 = icmp ult i32 %init, %N
249+
br i1 %c.1, label %loop.ph, label %exit
250+
251+
loop.ph:
252+
br label %loop
253+
254+
loop:
255+
%iv = phi i32 [ %iv.next, %loop ], [ %init, %loop.ph ]
256+
%iv.next = add i32 %iv, 1
257+
%exitcond = icmp eq i32 %iv.next, 10
258+
br i1 %exitcond, label %exit, label %loop
259+
260+
exit:
261+
ret void
262+
}
263+
264+
define void @crash(i8* %ptr) {
265+
; CHECK-LABEL: @crash
266+
; CHECK: Loop %while.body125: backedge-taken count is {(-2 + (-1 * %ptr)),+,-1}<nw><%while.cond111>
267+
; CHECK-NEXT: Loop %while.body125: max backedge-taken count is -1
268+
; CHECK-NEXT: Loop %while.body125: Predicated backedge-taken count is {(-2 + (-1 * %ptr)),+,-1}<nw><%while.cond111>
269+
;
270+
entry:
271+
br label %while.body
272+
273+
while.body:
274+
br label %while.cond111
275+
276+
while.cond111:
277+
%text.addr.5 = phi i8* [ %incdec.ptr112, %while.cond111 ], [ null, %while.body ]
278+
%incdec.ptr112 = getelementptr inbounds i8, i8* %text.addr.5, i64 -1
279+
br i1 false, label %while.end117, label %while.cond111
280+
281+
while.end117:
282+
%cmp118 = icmp ult i8* %ptr, %incdec.ptr112
283+
br i1 %cmp118, label %while.body125, label %while.cond134.preheader
284+
285+
286+
while.cond134.preheader:
287+
br label %while.body
288+
289+
while.body125:
290+
%lastout.2271 = phi i8* [ %incdec.ptr126, %while.body125 ], [ %ptr, %while.end117 ]
291+
%incdec.ptr126 = getelementptr inbounds i8, i8* %lastout.2271, i64 1
292+
%exitcond.not = icmp eq i8* %incdec.ptr126, %incdec.ptr112
293+
br i1 %exitcond.not, label %while.end129, label %while.body125
294+
295+
while.end129: ; preds = %while.body125
296+
ret void
297+
}

0 commit comments

Comments
 (0)