; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@A = weak global [1000 x i32] zeroinitializer, align 32
; The resulting predicate is i16 {0,+,1} <nssw>, meanining
; that the resulting backedge expression will be valid for:
; (1 + (-1 smax %M)) <= MAX_INT16
;
; At the limit condition for M (MAX_INT16 - 1) we have in the
; last iteration:
; i0 <- MAX_INT16
; i0.ext <- MAX_INT16
;
; and therefore no wrapping happend for i0 or i0.ext
; throughout the execution of the loop. The resulting predicated
; backedge taken count is correct.
define void @test1(i32 %N, i32 %M) {
; CHECK-LABEL: 'test1'
; CHECK-NEXT: Classifying expressions for: @test1
; CHECK-NEXT: %tmp = getelementptr [1000 x i32], ptr @A, i32 0, i16 %i.0
; CHECK-NEXT: --> ((4 * (sext i16 {0,+,1}<%bb3> to i64))<nsw> + @A) U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %tmp2 = add i16 %i.0, 1
; CHECK-NEXT: --> {1,+,1}<%bb3> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %i.0 = phi i16 [ 0, %entry ], [ %tmp2, %bb ]
; CHECK-NEXT: --> {0,+,1}<%bb3> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %i.0.ext = sext i16 %i.0 to i32
; CHECK-NEXT: --> (sext i16 {0,+,1}<%bb3> to i32) U: [-32768,32768) S: [-32768,32768) Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: Determining loop execution counts for: @test1
; CHECK-NEXT: Loop %bb3: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %bb3: Unpredictable constant max backedge-taken count.
; CHECK-NEXT: Loop %bb3: Unpredictable symbolic max backedge-taken count.
; CHECK-NEXT: Loop %bb3: Predicated backedge-taken count is (1 + (-1 smax %M))
; CHECK-NEXT: Predicates:
; CHECK-NEXT: {0,+,1}<%bb3> Added Flags: <nssw>
;
entry:
br label %bb3
bb: ; preds = %bb3
%tmp = getelementptr [1000 x i32], ptr @A, i32 0, i16 %i.0 ; <ptr> [#uses=1]
store i32 123, ptr %tmp
%tmp2 = add i16 %i.0, 1 ; <i32> [#uses=1]
br label %bb3
bb3: ; preds = %bb, %entry
%i.0 = phi i16 [ 0, %entry ], [ %tmp2, %bb ] ; <i32> [#uses=3]
%i.0.ext = sext i16 %i.0 to i32
%tmp3 = icmp sle i32 %i.0.ext, %M ; <i1> [#uses=1]
br i1 %tmp3, label %bb, label %bb5
bb5: ; preds = %bb3
br label %return
return: ; preds = %bb5
ret void
}
; The predicated backedge taken count is:
; (2 + (zext i16 %Start to i32) + ((-2 + (-1 * (sext i16 %Start to i32)))
; smax (-1 + (-1 * %M)))
; )
; -1 + (-1 * %M) <= (-2 + (-1 * (sext i16 %Start to i32))
; The predicated backedge taken count is 0.
; From the IR, this is correct since we will bail out at the
; first iteration.
; * -1 + (-1 * %M) > (-2 + (-1 * (sext i16 %Start to i32))
; or: %M < 1 + (sext i16 %Start to i32)
;
; The predicated backedge taken count is 1 + (zext i16 %Start to i32) - %M
;
; If %M >= MIN_INT + 1, this predicated backedge taken count would be correct (even
; without predicates). However, for %M < MIN_INT this would be an infinite loop.
; In these cases, the {%Start,+,-1} <nusw> predicate would be false, as the
; final value of the expression {%Start,+,-1} expression (%M - 1) would not be
; representable as an i16.
; There is also a limit case here where the value of %M is MIN_INT. In this case
; we still have an infinite loop, since icmp sge %x, MIN_INT will always return
; true.
define void @test2(i32 %N, i32 %M, i16 %Start) {
; CHECK-LABEL: 'test2'
; CHECK-NEXT: Classifying expressions for: @test2
; CHECK-NEXT: %tmp = getelementptr [1000 x i32], ptr @A, i32 0, i16 %i.0
; CHECK-NEXT: --> ((4 * (sext i16 {%Start,+,-1}<%bb3> to i64))<nsw> + @A) U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %tmp2 = sub i16 %i.0, 1
; CHECK-NEXT: --> {(-1 + %Start),+,-1}<%bb3> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %i.0 = phi i16 [ %Start, %entry ], [ %tmp2, %bb ]
; CHECK-NEXT: --> {%Start,+,-1}<%bb3> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: %i.0.ext = sext i16 %i.0 to i32
; CHECK-NEXT: --> (sext i16 {%Start,+,-1}<%bb3> to i32) U: [-32768,32768) S: [-32768,32768) Exits: <<Unknown>> LoopDispositions: { %bb3: Computable }
; CHECK-NEXT: Determining loop execution counts for: @test2
; CHECK-NEXT: Loop %bb3: Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %bb3: Unpredictable constant max backedge-taken count.
; CHECK-NEXT: Loop %bb3: Unpredictable symbolic max backedge-taken count.
; CHECK-NEXT: Loop %bb3: Predicated backedge-taken count is (1 + (sext i16 %Start to i32) + (-1 * ((1 + (sext i16 %Start to i32))<nsw> smin %M)))
; CHECK-NEXT: Predicates:
; CHECK-NEXT: {%Start,+,-1}<%bb3> Added Flags: <nssw>
;
entry:
br label %bb3
bb: ; preds = %bb3
%tmp = getelementptr [1000 x i32], ptr @A, i32 0, i16 %i.0 ; <ptr> [#uses=1]
store i32 123, ptr %tmp
%tmp2 = sub i16 %i.0, 1 ; <i32> [#uses=1]
br label %bb3
bb3: ; preds = %bb, %entry
%i.0 = phi i16 [ %Start, %entry ], [ %tmp2, %bb ] ; <i32> [#uses=3]
%i.0.ext = sext i16 %i.0 to i32
%tmp3 = icmp sge i32 %i.0.ext, %M ; <i1> [#uses=1]
br i1 %tmp3, label %bb, label %bb5
bb5: ; preds = %bb3
br label %return
return: ; preds = %bb5
ret void
}
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