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llvm-project/llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll

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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
; RUN: opt -analyze -enable-new-pm=0 -scalar-evolution < %s | FileCheck %s
; RUN: opt -disable-output "-passes=print<scalar-evolution>" < %s 2>&1 | FileCheck %s
define void @test_lshr() {
; CHECK-LABEL: 'test_lshr'
; CHECK-NEXT: Classifying expressions for: @test_lshr
; CHECK-NEXT: %iv.lshr = phi i64 [ 1023, %entry ], [ %iv.lshr.next, %loop ]
; CHECK-NEXT: --> %iv.lshr U: [0,1024) S: [0,1024) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.lshr.next = lshr i64 %iv.lshr, 1
; CHECK-NEXT: --> (%iv.lshr /u 2) U: [0,512) S: [0,512) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_lshr
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.lshr = phi i64 [1023, %entry], [%iv.lshr.next, %loop]
%iv.lshr.next = lshr i64 %iv.lshr, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
; Deliberate overflow doesn't change range
define void @test_lshr2() {
; CHECK-LABEL: 'test_lshr2'
; CHECK-NEXT: Classifying expressions for: @test_lshr2
; CHECK-NEXT: %iv.lshr = phi i64 [ 1023, %entry ], [ %iv.lshr.next, %loop ]
; CHECK-NEXT: --> %iv.lshr U: [0,1024) S: [0,1024) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.lshr.next = lshr i64 %iv.lshr, 4
; CHECK-NEXT: --> (%iv.lshr /u 16) U: [0,64) S: [0,64) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_lshr2
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.lshr = phi i64 [1023, %entry], [%iv.lshr.next, %loop]
%iv.lshr.next = lshr i64 %iv.lshr, 4
br i1 undef, label %exit, label %loop
exit:
ret void
}
define void @test_ashr_zeros() {
; CHECK-LABEL: 'test_ashr_zeros'
; CHECK-NEXT: Classifying expressions for: @test_ashr_zeros
; CHECK-NEXT: %iv.ashr = phi i64 [ 1023, %entry ], [ %iv.ashr.next, %loop ]
; CHECK-NEXT: --> %iv.ashr U: [0,1024) S: [0,1024) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.ashr.next = ashr i64 %iv.ashr, 1
; CHECK-NEXT: --> %iv.ashr.next U: [0,512) S: [0,512) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_ashr_zeros
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [1023, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
define void @test_ashr_ones() {
; CHECK-LABEL: 'test_ashr_ones'
; CHECK-NEXT: Classifying expressions for: @test_ashr_ones
; CHECK-NEXT: %iv.ashr = phi i64 [ -1023, %entry ], [ %iv.ashr.next, %loop ]
; CHECK-NEXT: --> %iv.ashr U: [-1023,0) S: [-1023,0) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.ashr.next = ashr i64 %iv.ashr, 1
; CHECK-NEXT: --> %iv.ashr.next U: [-512,0) S: [-512,0) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_ashr_ones
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [-1023, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
; Same as previous, but swapped operands to phi
define void @test_ashr_ones2() {
; CHECK-LABEL: 'test_ashr_ones2'
; CHECK-NEXT: Classifying expressions for: @test_ashr_ones2
; CHECK-NEXT: %iv.ashr = phi i64 [ %iv.ashr.next, %loop ], [ -1023, %entry ]
; CHECK-NEXT: --> %iv.ashr U: [-1023,0) S: [-1023,0) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.ashr.next = ashr i64 %iv.ashr, 1
; CHECK-NEXT: --> %iv.ashr.next U: [-512,0) S: [-512,0) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_ashr_ones2
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%iv.ashr.next, %loop], [-1023, %entry]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
; negative case for when start is unknown
define void @test_ashr_unknown(i64 %start) {
; CHECK-LABEL: 'test_ashr_unknown'
; CHECK-NEXT: Classifying expressions for: @test_ashr_unknown
; CHECK-NEXT: %iv.ashr = phi i64 [ %start, %entry ], [ %iv.ashr.next, %loop ]
; CHECK-NEXT: --> %iv.ashr U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.ashr.next = ashr i64 %iv.ashr, 1
; CHECK-NEXT: --> %iv.ashr.next U: [-4611686018427387904,4611686018427387904) S: [-4611686018427387904,4611686018427387904) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_ashr_unknown
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%start, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 %iv.ashr, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
; Negative case where we don't have a (shift) recurrence because the operands
; of the ashr are swapped. (This does end up being a divide recurrence.)
define void @test_ashr_wrong_op(i64 %start) {
; CHECK-LABEL: 'test_ashr_wrong_op'
; CHECK-NEXT: Classifying expressions for: @test_ashr_wrong_op
; CHECK-NEXT: %iv.ashr = phi i64 [ %start, %entry ], [ %iv.ashr.next, %loop ]
; CHECK-NEXT: --> %iv.ashr U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.ashr.next = ashr i64 1, %iv.ashr
; CHECK-NEXT: --> %iv.ashr.next U: [-2,2) S: [-2,2) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_ashr_wrong_op
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.ashr = phi i64 [%start, %entry], [%iv.ashr.next, %loop]
%iv.ashr.next = ashr i64 1, %iv.ashr
br i1 undef, label %exit, label %loop
exit:
ret void
}
define void @test_shl() {
; CHECK-LABEL: 'test_shl'
; CHECK-NEXT: Classifying expressions for: @test_shl
; CHECK-NEXT: %iv.shl = phi i64 [ 8, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-7) S: [-9223372036854775808,9223372036854775793) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, 1
; CHECK-NEXT: --> (2 * %iv.shl) U: [0,-15) S: [-9223372036854775808,9223372036854775793) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl
; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable max backedge-taken count.
; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
;
entry:
br label %loop
loop:
%iv.shl = phi i64 [8, %entry], [%iv.shl.next, %loop]
%iv.shl.next = shl i64 %iv.shl, 1
br i1 undef, label %exit, label %loop
exit:
ret void
}
; use trip count to refine
define void @test_shl2() {
; CHECK-LABEL: 'test_shl2'
; CHECK-NEXT: Classifying expressions for: @test_shl2
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,5) S: [0,5) Exits: 4 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775801) Exits: 64 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,6) S: [1,6) Exits: 5 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, 1
; CHECK-NEXT: --> (2 * %iv.shl) U: [0,-7) S: [-9223372036854775808,9223372036854775801) Exits: 128 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl2
; CHECK-NEXT: Loop %loop: backedge-taken count is 4
; CHECK-NEXT: Loop %loop: max backedge-taken count is 4
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 4
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 5
;
entry:
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, 1
%cmp = icmp eq i64 %iv, 4
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
; Variable shift with a tight upper bound
define void @test_shl3(i1 %c) {
; CHECK-LABEL: 'test_shl3'
; CHECK-NEXT: Classifying expressions for: @test_shl3
; CHECK-NEXT: %shiftamt = select i1 %c, i64 1, i64 0
; CHECK-NEXT: --> %shiftamt U: [0,2) S: [0,2)
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,5) S: [0,5) Exits: 4 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,6) S: [1,6) Exits: 5 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, %shiftamt
; CHECK-NEXT: --> %iv.shl.next U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl3
; CHECK-NEXT: Loop %loop: backedge-taken count is 4
; CHECK-NEXT: Loop %loop: max backedge-taken count is 4
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 4
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 5
;
entry:
%shiftamt = select i1 %c, i64 1, i64 0
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, %shiftamt
%cmp = icmp eq i64 %iv, 4
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
; edge case on max value not overflowing
define void @test_shl4() {
; CHECK-LABEL: 'test_shl4'
; CHECK-NEXT: Classifying expressions for: @test_shl4
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,61) S: [0,61) Exits: 60 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775801) Exits: 4611686018427387904 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,62) S: [1,62) Exits: 61 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, 1
; CHECK-NEXT: --> (2 * %iv.shl) U: [0,-7) S: [-9223372036854775808,9223372036854775801) Exits: -9223372036854775808 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl4
; CHECK-NEXT: Loop %loop: backedge-taken count is 60
; CHECK-NEXT: Loop %loop: max backedge-taken count is 60
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 60
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 61
;
entry:
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, 1
%cmp = icmp eq i64 %iv, 60
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
; other side of edge case from previous test
define void @test_shl5() {
; CHECK-LABEL: 'test_shl5'
; CHECK-NEXT: Classifying expressions for: @test_shl5
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,62) S: [0,62) Exits: 61 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775801) Exits: -9223372036854775808 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,63) S: [1,63) Exits: 62 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, 1
; CHECK-NEXT: --> (2 * %iv.shl) U: [0,-7) S: [-9223372036854775808,9223372036854775801) Exits: 0 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl5
; CHECK-NEXT: Loop %loop: backedge-taken count is 61
; CHECK-NEXT: Loop %loop: max backedge-taken count is 61
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 61
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 62
;
entry:
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, 1
%cmp = icmp eq i64 %iv, 61
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
; Loop varying (but tightly bounded) shift amount
define void @test_shl6(i1 %c) {
; CHECK-LABEL: 'test_shl6'
; CHECK-NEXT: Classifying expressions for: @test_shl6
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,5) S: [0,5) Exits: 4 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: 16 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,6) S: [1,6) Exits: 5 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %shiftamt = and i64 %iv, 1
; CHECK-NEXT: --> (zext i1 {false,+,true}<%loop> to i64) U: [0,2) S: [0,2) Exits: 0 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, %shiftamt
; CHECK-NEXT: --> %iv.shl.next U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: 16 LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl6
; CHECK-NEXT: Loop %loop: backedge-taken count is 4
; CHECK-NEXT: Loop %loop: max backedge-taken count is 4
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 4
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 5
;
entry:
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%shiftamt = and i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, %shiftamt
%cmp = icmp eq i64 %iv, 4
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
; Unanalyzeable shift amount
define void @test_shl7(i1 %c, i64 %shiftamt) {
; CHECK-LABEL: 'test_shl7'
; CHECK-NEXT: Classifying expressions for: @test_shl7
; CHECK-NEXT: %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-NEXT: --> {0,+,1}<%loop> U: [0,5) S: [0,5) Exits: 4 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
; CHECK-NEXT: --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: %iv.next = add i64 %iv, 1
; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,6) S: [1,6) Exits: 5 LoopDispositions: { %loop: Computable }
; CHECK-NEXT: %iv.shl.next = shl i64 %iv.shl, %shiftamt
; CHECK-NEXT: --> %iv.shl.next U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
; CHECK-NEXT: Determining loop execution counts for: @test_shl7
; CHECK-NEXT: Loop %loop: backedge-taken count is 4
; CHECK-NEXT: Loop %loop: max backedge-taken count is 4
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 4
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 5
;
entry:
br label %loop
loop:
%iv = phi i64 [0, %entry], [%iv.next, %loop]
%iv.shl = phi i64 [4, %entry], [%iv.shl.next, %loop]
%iv.next = add i64 %iv, 1
%iv.shl.next = shl i64 %iv.shl, %shiftamt
%cmp = icmp eq i64 %iv, 4
br i1 %cmp, label %exit, label %loop
exit:
ret void
}
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