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llvm-mirror/test/Analysis/ScalarEvolution/sdiv.ll
Nikita Popov 318f4a3446 [SCEV] Fix nsw flags for GEP expressions
The SCEV code for constructing GEP expressions currently assumes
that the addition of the base and all the offsets is nsw if the GEP
is inbounds. While the addition of the offsets is indeed nsw, the
addition to the base address is not, as the base address is
interpreted as an unsigned value.

Fix the GEP expression code to not assume nsw for the base+offset
calculation. However, do assume nuw if we know that the offset is
non-negative. With this, we use the same behavior as the
construction of GEP addrecs does. (Modulo the fact that we
disregard SCEV unification, as the pre-existing FIXME points out).

Differential Revision: https://reviews.llvm.org/D90648
2020-11-13 18:19:32 +01:00

76 lines
4.0 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
; RUN: opt < %s -scalar-evolution -analyze -enable-new-pm=0 | FileCheck %s
; RUN: opt < %s "-passes=print<scalar-evolution>" -disable-output 2>&1 | 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 = sdiv i32 %i.0, 2
; CHECK-NEXT: --> ({0,+,1}<nuw><nsw><%for.cond> /u 2) U: [0,1073741824) S: [0,1073741824) Exits: (%width /u 2) LoopDispositions: { %for.cond: Computable }
; CHECK-NEXT: %idxprom = sext i32 %rem to i64
; CHECK-NEXT: --> ({0,+,1}<nuw><nsw><%for.cond> /u 2) U: [0,2147483648) S: [0,2147483648) Exits: ((zext i32 %width to i64) /u 2) LoopDispositions: { %for.cond: Computable }
; CHECK-NEXT: %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* %storage, i64 0, i64 %idxprom
; CHECK-NEXT: --> ((4 * ({0,+,1}<nuw><nsw><%for.cond> /u 2))<nuw><nsw> + %storage)<nuw> U: [0,-3) S: [-9223372036854775808,9223372036854775805) Exits: ((4 * ((zext i32 %width to i64) /u 2))<nuw><nsw> + %storage)<nuw> LoopDispositions: { %for.cond: Computable }
; 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 = sdiv 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