Files
archived-llvm/test/Transforms/LoopUnroll/runtime-loop.ll
Hans Wennborg 7f2c699402 Merging r229731:
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r229731 | sanjoy | 2015-02-18 11:32:25 -0800 (Wed, 18 Feb 2015) | 10 lines

Partial fix for bug 22589

Don't spend the entire iteration space in the scalar loop prologue if
computing the trip count overflows.  This change also gets rid of the
backedge check in the prologue loop and the extra check for
overflowing trip-count.

Differential Revision: http://reviews.llvm.org/D7715


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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@229757 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 22:51:15 +00:00

119 lines
4.1 KiB
LLVM

; RUN: opt < %s -S -loop-unroll -unroll-runtime=true | FileCheck %s
; Tests for unrolling loops with run-time trip counts
; CHECK: %xtraiter = and i32 %n
; CHECK: %lcmp.mod = icmp ne i32 %xtraiter, 0
; CHECK: br i1 %lcmp.mod, label %for.body.prol, label %for.body.preheader.split
; CHECK: for.body.prol:
; CHECK: %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %for.body.prol ], [ 0, %for.body.preheader ]
; CHECK: %prol.iter.sub = sub i32 %prol.iter, 1
; CHECK: %prol.iter.cmp = icmp ne i32 %prol.iter.sub, 0
; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.preheader.split, !llvm.loop !0
define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
entry:
%cmp1 = icmp eq i32 %n, 0
br i1 %cmp1, label %for.end, label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%sum.02 = phi i32 [ %add, %for.body ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
%0 = load i32* %arrayidx, align 4
%add = add nsw i32 %0, %sum.02
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %entry
%sum.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.body ]
ret i32 %sum.0.lcssa
}
; Still try to completely unroll loops with compile-time trip counts
; even if the -unroll-runtime is specified
; CHECK: for.body:
; CHECK-NOT: for.body.prol:
define i32 @test1(i32* nocapture %a) nounwind uwtable readonly {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%sum.01 = phi i32 [ 0, %entry ], [ %add, %for.body ]
%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
%0 = load i32* %arrayidx, align 4
%add = add nsw i32 %0, %sum.01
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 5
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret i32 %add
}
; This is test 2007-05-09-UnknownTripCount.ll which can be unrolled now
; if the -unroll-runtime option is turned on
; CHECK: bb72.2:
define void @foo(i32 %trips) {
entry:
br label %cond_true.outer
cond_true.outer:
%indvar1.ph = phi i32 [ 0, %entry ], [ %indvar.next2, %bb72 ]
br label %bb72
bb72:
%indvar.next2 = add i32 %indvar1.ph, 1
%exitcond3 = icmp eq i32 %indvar.next2, %trips
br i1 %exitcond3, label %cond_true138, label %cond_true.outer
cond_true138:
ret void
}
; Test run-time unrolling for a loop that counts down by -2.
; CHECK: for.body.prol:
; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.preheader.split
define zeroext i16 @down(i16* nocapture %p, i32 %len) nounwind uwtable readonly {
entry:
%cmp2 = icmp eq i32 %len, 0
br i1 %cmp2, label %for.end, label %for.body
for.body: ; preds = %for.body, %entry
%p.addr.05 = phi i16* [ %incdec.ptr, %for.body ], [ %p, %entry ]
%len.addr.04 = phi i32 [ %sub, %for.body ], [ %len, %entry ]
%res.03 = phi i32 [ %add, %for.body ], [ 0, %entry ]
%incdec.ptr = getelementptr inbounds i16* %p.addr.05, i64 1
%0 = load i16* %p.addr.05, align 2
%conv = zext i16 %0 to i32
%add = add i32 %conv, %res.03
%sub = add nsw i32 %len.addr.04, -2
%cmp = icmp eq i32 %sub, 0
br i1 %cmp, label %for.cond.for.end_crit_edge, label %for.body
for.cond.for.end_crit_edge: ; preds = %for.body
%phitmp = trunc i32 %add to i16
br label %for.end
for.end: ; preds = %for.cond.for.end_crit_edge, %entry
%res.0.lcssa = phi i16 [ %phitmp, %for.cond.for.end_crit_edge ], [ 0, %entry ]
ret i16 %res.0.lcssa
}
; CHECK: !0 = distinct !{!0, !1}
; CHECK: !1 = !{!"llvm.loop.unroll.disable"}