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llvm-mirror/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll
Wei Mi d25dea67a3 [UNROLL] Postpone ScalarEvolution::forgetLoop after TripCountSC is expanded
when unroll runtime iteration loop.

In llvm::UnrollRuntimeLoopRemainder, if the loop to be unrolled is the inner
loop inside a loop nest, the scalar evolution needs to be dropped for its
parent loop which is done by ScalarEvolution::forgetLoop. However, we can
postpone forgetLoop to the end of UnrollRuntimeLoopRemainder so TripCountSC
expansion can still reuse existing value.

Differential Revision: https://reviews.llvm.org/D23572

llvm-svn: 279748
2016-08-25 16:17:18 +00:00

41 lines
1.5 KiB
LLVM

; RUN: opt < %s -loop-vectorize -force-vector-width=4 -verify-scev-maps -S |FileCheck %s
; SCEV expansion uses existing value when the SCEV has no AddRec expr.
; CHECK-LABEL: @foo(
; CHECK: select
; CHECK-NOT: select
; CHECK: ret
@a = common global [1000 x i16] zeroinitializer, align 16
define i32 @foo(i32 %x, i32 %y) {
entry:
%cmp = icmp slt i32 %x, %y
%cond = select i1 %cmp, i32 %x, i32 %y
%cmp1.10 = icmp sgt i32 %cond, 0
br i1 %cmp1.10, label %for.body.lr.ph, label %for.end
for.body.lr.ph: ; preds = %entry
%tmp = sext i32 %cond to i64
br label %for.body
for.body: ; preds = %for.body, %for.body.lr.ph
%indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
%total.011 = phi i32 [ 0, %for.body.lr.ph ], [ %add, %for.body ]
%arrayidx = getelementptr inbounds [1000 x i16], [1000 x i16]* @a, i64 0, i64 %indvars.iv
%tmp1 = load i16, i16* %arrayidx, align 2
%conv = sext i16 %tmp1 to i32
%add = add nsw i32 %conv, %total.011
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%cmp1 = icmp slt i64 %indvars.iv.next, %tmp
br i1 %cmp1, label %for.body, label %for.end.loopexit
for.end.loopexit: ; preds = %for.body
%add.lcssa = phi i32 [ %add, %for.body ]
br label %for.end
for.end: ; preds = %for.end.loopexit, %entry
%total.0.lcssa = phi i32 [ 0, %entry ], [ %add.lcssa, %for.end.loopexit ]
ret i32 %total.0.lcssa
}