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llvm-mirror/test/Transforms/LoopStrengthReduce/scev-insertpt-bug.ll
Geoff Berry 13fd91db82 Reapply [LSR] Create fewer redundant instructions.
Summary:
Fix LSRInstance::HoistInsertPosition() to check the original insert
position block first for a canonical insertion point that is dominated
by all inputs.  This leads to SCEV being able to reuse more instructions
since it currently tracks the instructions it creates for reuse by
keeping a table of <Value, insert point> pairs.

Originally reviewed in http://reviews.llvm.org/D18001

Reviewers: atrick

Subscribers: llvm-commits, mzolotukhin, mcrosier

Differential Revision: http://reviews.llvm.org/D18480

llvm-svn: 271929
2016-06-06 19:10:46 +00:00

48 lines
1.6 KiB
LLVM

; RUN: opt < %s -loop-reduce -S
; Test that SCEV insertpoint's don't get corrupted and cause an
; invalid instruction to be inserted in a block other than its parent.
; See http://reviews.llvm.org/D20703 for context.
define void @test() {
entry:
%bf.load = load i32, i32* null, align 4
%bf.clear = lshr i32 %bf.load, 1
%div = and i32 %bf.clear, 134217727
%sub = add nsw i32 %div, -1
%0 = zext i32 %sub to i64
br label %while.cond
while.cond: ; preds = %cond.end, %entry
%indvars.iv = phi i64 [ %indvars.iv.next, %cond.end ], [ 0, %entry ]
%cmp = icmp eq i64 %indvars.iv, %0
br i1 %cmp, label %cleanup16, label %while.body
while.body: ; preds = %while.cond
%1 = trunc i64 %indvars.iv to i32
%mul = shl i32 %1, 1
%add = add nuw i32 %mul, 2
%cmp3 = icmp ult i32 %add, 0
br i1 %cmp3, label %if.end, label %if.then
if.then: ; preds = %while.body
unreachable
if.end: ; preds = %while.body
br i1 false, label %cond.end, label %cond.true
cond.true: ; preds = %if.end
br label %cond.end
cond.end: ; preds = %cond.true, %if.end
%add7 = add i32 %1, 1
%cmp12 = icmp ugt i32 %add7, %sub
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br i1 %cmp12, label %if.then13, label %while.cond
if.then13: ; preds = %cond.end
unreachable
cleanup16: ; preds = %while.cond
ret void
}