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[LoopUnroll] Fix bug in computeUnrollCount causing it to not honor MaxCount 

Reviewers: sanjoy, anna, reames, apilipenko, igor-laevsky, mkuper

Subscribers: mcrosier, llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D34532

llvm-svn: 306564
This commit is contained in:
Geoff Berry 2017-06-28 17:01:15 +00:00
parent 1a132d27c6
commit b0573547f6
2 changed files with 33 additions and 0 deletions
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2
llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
View File

@ -836,6 +836,8 @@ static bool computeUnrollCount(
} else {
UP.Count = TripCount;
}
if (UP.Count > UP.MaxCount)
UP.Count = UP.MaxCount;
if ((PragmaFullUnroll || PragmaEnableUnroll) && TripCount &&
UP.Count != TripCount)
ORE->emit(

31
llvm/test/Transforms/LoopUnroll/unroll-maxcount.ll Normal file
View File

@ -0,0 +1,31 @@
; RUN: opt < %s -S -loop-unroll -unroll-allow-partial -unroll-max-count=1 | FileCheck %s
; Checks that unroll MaxCount is honored.
;
; CHECK-LABEL: @foo(
; CHECK-LABEL: for.body:
; CHECK-NEXT: phi
; CHECK-NEXT: getelementptr
; CHECK-NEXT: load
; CHECK-NEXT: add
; CHECK-NEXT: store
; CHECK-NEXT: add
; CHECK-NEXT: icmp
; CHECK-NEXT: br
define void @foo(i32* nocapture %a) {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
%0 = load i32, i32* %arrayidx, align 4
%inc = add nsw i32 %0, 1
store i32 %inc, i32* %arrayidx, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 1024
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}