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[NFC][ScalarEvolution] Add a test showing SCEV failure to recognize 'urem' 

While InstCombine trivially converts that `srem` into a `urem`,
it might happen later than wanted. SCEV should recognize this natively.
This commit is contained in:
Roman Lebedev 2020-06-28 20:31:14 +03:00
parent c8755b6378
commit 25521150d7
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1 changed files with 74 additions and 0 deletions
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llvm/test/Analysis/ScalarEvolution/srem.ll Normal file
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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
; RUN: opt < %s -scalar-evolution -analyze | FileCheck %s
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define dso_local void @_Z4loopi(i32 %width) local_unnamed_addr #0 {
; CHECK-LABEL: '_Z4loopi'
; CHECK-NEXT: Classifying expressions for: @_Z4loopi
; CHECK-NEXT: %storage = alloca [2 x i32], align 4
; CHECK-NEXT: --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
; CHECK-NEXT: %0 = bitcast [2 x i32]* %storage to i8*
; CHECK-NEXT: --> %storage U: [0,-3) S: [-9223372036854775808,9223372036854775805)
; CHECK-NEXT: %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%for.cond> U: [0,-2147483648) S: [0,-2147483648) Exits: %width LoopDispositions: { %for.cond: Computable }
; CHECK-NEXT: %rem = srem i32 %i.0, 2
; CHECK-NEXT: --> %rem U: [0,2) S: [-2,2) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %idxprom = sext i32 %rem to i64
; CHECK-NEXT: --> (sext i32 %rem to i64) U: [0,2) S: [-2,2) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* %storage, i64 0, i64 %idxprom
; CHECK-NEXT: --> ((4 * (sext i32 %rem to i64))<nuw><nsw> + %storage)<nsw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %1 = load i32, i32* %arrayidx, align 4
; CHECK-NEXT: --> %1 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %call = call i32 @_Z3adji(i32 %1)
; CHECK-NEXT: --> %call U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %2 = load i32, i32* %arrayidx, align 4
; CHECK-NEXT: --> %2 U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %add = add nsw i32 %2, %call
; CHECK-NEXT: --> (%2 + %call) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %for.cond: Variant }
; CHECK-NEXT: %inc = add nsw i32 %i.0, 1
; CHECK-NEXT: --> {1,+,1}<nuw><%for.cond> U: [1,0) S: [1,0) Exits: (1 + %width) LoopDispositions: { %for.cond: Computable }
; CHECK-NEXT: Determining loop execution counts for: @_Z4loopi
; CHECK-NEXT: Loop %for.cond: backedge-taken count is %width
; CHECK-NEXT: Loop %for.cond: max backedge-taken count is -1
; CHECK-NEXT: Loop %for.cond: Predicated backedge-taken count is %width
; CHECK-NEXT: Predicates:
; CHECK: Loop %for.cond: Trip multiple is 1
;
entry:
%storage = alloca [2 x i32], align 4
%0 = bitcast [2 x i32]* %storage to i8*
call void @llvm.lifetime.start.p0i8(i64 8, i8* %0) #4
call void @llvm.memset.p0i8.i64(i8* align 4 %0, i8 0, i64 8, i1 false)
br label %for.cond
for.cond:
%i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
%cmp = icmp ne i32 %i.0, %width
br i1 %cmp, label %for.body, label %for.cond.cleanup
for.cond.cleanup:
call void @llvm.lifetime.end.p0i8(i64 8, i8* %0) #4
ret void
for.body:
%rem = srem i32 %i.0, 2
%idxprom = sext i32 %rem to i64
%arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* %storage, i64 0, i64 %idxprom
%1 = load i32, i32* %arrayidx, align 4
%call = call i32 @_Z3adji(i32 %1)
%2 = load i32, i32* %arrayidx, align 4
%add = add nsw i32 %2, %call
store i32 %add, i32* %arrayidx, align 4
%inc = add nsw i32 %i.0, 1
br label %for.cond
}
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg) #2
declare dso_local i32 @_Z3adji(i32) local_unnamed_addr #3
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1