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[SCEV] Precommit tests with signed counting down loop. 

From PR46939.
This commit is contained in:
Florian Hahn 2020-07-31 22:10:39 +01:00
parent 21c165de2a
commit ffb4735200
1 changed files with 38 additions and 0 deletions
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38
llvm/test/Analysis/ScalarEvolution/pr46939-trip-count-count-down.ll Normal file
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; RUN: opt -analyze -scalar-evolution %s 2>&1 | FileCheck %s
declare void @iteration()
define void @reverse_loop(i32 %n) {
; CHECK-LABEL: 'reverse_loop'
; CHECK-NEXT: Classifying expressions for: @reverse_loop
; CHECK-NEXT: %i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
; CHECK-NEXT: --> {%n,+,-1}<nsw><%for.body> U: full-set S: full-set Exits: (0 smin %n) LoopDispositions: { %for.body: Computable }
; CHECK-NEXT: %dec = add nsw i32 %i.011, -1
; CHECK-NEXT: --> {(-1 + %n),+,-1}<nw><%for.body> U: full-set S: full-set Exits: (-1 + (0 smin %n)) LoopDispositions: { %for.body: Computable }
; CHECK-NEXT: Determining loop execution counts for: @reverse_loop
; CHECK-NEXT: Loop %for.body: backedge-taken count is ((-1 * (0 smin %n)) + %n)
; CHECK-NEXT: Loop %for.body: max backedge-taken count is 2147483647
; CHECK-NEXT: Loop %for.body: Predicated backedge-taken count is ((-1 * (0 smin %n)) + %n)
; CHECK-NEXT: Predicates:
; CHECK: Loop %for.body: Trip multiple is 1
;
entry:
%cmp10 = icmp sgt i32 %n, -1
br i1 %cmp10, label %for.body.lr.ph, label %for.cond.cleanup
for.body.lr.ph:
br label %for.body
for.body:
%i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
call void @iteration()
%dec = add nsw i32 %i.011, -1
%cmp = icmp sgt i32 %i.011, 0
br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
for.cond.cleanup.loopexit:
br label %for.cond.cleanup
for.cond.cleanup:
ret void
}