[llvm] r330250 - [LoopUnroll] Only peel if a predicate becomes known in the loop body.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 18 05:29:24 PDT 2018
Author: fhahn
Date: Wed Apr 18 05:29:24 2018
New Revision: 330250
URL: http://llvm.org/viewvc/llvm-project?rev=330250&view=rev
Log:
[LoopUnroll] Only peel if a predicate becomes known in the loop body.
If a predicate does not become known after peeling, peeling is unlikely
to be beneficial.
Reviewers: mcrosier, efriedma, mkazantsev, junbuml
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D44983
Modified:
llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp
llvm/trunk/test/Transforms/LoopUnroll/peel-loop-conditions.ll
Modified: llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp?rev=330250&r1=330249&r2=330250&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp Wed Apr 18 05:29:24 2018
@@ -190,14 +190,25 @@ static unsigned countToEliminateCompares
const SCEVAddRecExpr *LeftAR = cast<SCEVAddRecExpr>(LeftSCEV);
- // Avoid huge SCEV computations in the loop below and make sure we only
- // consider AddRecs of the loop we are trying to peel.
- if (!LeftAR->isAffine() || LeftAR->getLoop() != &L)
+ // Avoid huge SCEV computations in the loop below, make sure we only
+ // consider AddRecs of the loop we are trying to peel and avoid
+ // non-monotonic predicates, as we will not be able to simplify the loop
+ // body.
+ // FIXME: For the non-monotonic predicates ICMP_EQ and ICMP_NE we can
+ // simplify the loop, if we peel 1 additional iteration, if there
+ // is no wrapping.
+ bool Increasing;
+ if (!LeftAR->isAffine() || LeftAR->getLoop() != &L ||
+ !SE.isMonotonicPredicate(LeftAR, Pred, Increasing))
continue;
+ (void)Increasing;
+
+ // Check if extending the current DesiredPeelCount lets us evaluate Pred
+ // or !Pred in the loop body statically.
+ unsigned NewPeelCount = DesiredPeelCount;
- // Check if extending DesiredPeelCount lets us evaluate Pred.
const SCEV *IterVal = LeftAR->evaluateAtIteration(
- SE.getConstant(LeftSCEV->getType(), DesiredPeelCount), SE);
+ SE.getConstant(LeftSCEV->getType(), NewPeelCount), SE);
// If the original condition is not known, get the negated predicate
// (which holds on the else branch) and check if it is known. This allows
@@ -206,11 +217,18 @@ static unsigned countToEliminateCompares
Pred = ICmpInst::getInversePredicate(Pred);
const SCEV *Step = LeftAR->getStepRecurrence(SE);
- while (DesiredPeelCount < MaxPeelCount &&
+ while (NewPeelCount < MaxPeelCount &&
SE.isKnownPredicate(Pred, IterVal, RightSCEV)) {
IterVal = SE.getAddExpr(IterVal, Step);
- DesiredPeelCount++;
+ NewPeelCount++;
}
+
+ // Only peel the loop if the monotonic predicate !Pred becomes known in the
+ // first iteration of the loop body after peeling.
+ if (NewPeelCount > DesiredPeelCount &&
+ SE.isKnownPredicate(ICmpInst::getInversePredicate(Pred), IterVal,
+ RightSCEV))
+ DesiredPeelCount = NewPeelCount;
}
return DesiredPeelCount;
Modified: llvm/trunk/test/Transforms/LoopUnroll/peel-loop-conditions.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/peel-loop-conditions.ll?rev=330250&r1=330249&r2=330250&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/peel-loop-conditions.ll (original)
+++ llvm/trunk/test/Transforms/LoopUnroll/peel-loop-conditions.ll Wed Apr 18 05:29:24 2018
@@ -338,114 +338,23 @@ for.end:
ret void
}
-; Test that we respect MaxPeelCount
+; Test that we only peel off iterations if it simplifies a condition in the
+; loop body after peeling at most MaxPeelCount iterations.
define void @test4(i32 %k) {
; CHECK-LABEL: @test4(
; CHECK-NEXT: for.body.lr.ph:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL_BEGIN:%.*]]
-; CHECK: for.body.peel.begin:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL:%.*]]
-; CHECK: for.body.peel:
-; CHECK-NEXT: [[CMP1_PEEL:%.*]] = icmp ugt i32 0, 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL]], label [[IF_THEN_PEEL:%.*]], label [[FOR_INC_PEEL:%.*]]
-; CHECK: if.then.peel:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL]]
-; CHECK: for.inc.peel:
-; CHECK-NEXT: [[INC_PEEL:%.*]] = add nsw i32 0, 1
-; CHECK-NEXT: [[CMP_PEEL:%.*]] = icmp slt i32 [[INC_PEEL]], [[K:%.*]]
-; CHECK-NEXT: br i1 [[CMP_PEEL]], label [[FOR_BODY_PEEL_NEXT:%.*]], label [[FOR_END:%.*]]
-; CHECK: for.body.peel.next:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL2:%.*]]
-; CHECK: for.body.peel2:
-; CHECK-NEXT: [[CMP1_PEEL3:%.*]] = icmp ugt i32 [[INC_PEEL]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL3]], label [[IF_THEN_PEEL4:%.*]], label [[FOR_INC_PEEL5:%.*]]
-; CHECK: if.then.peel4:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL5]]
-; CHECK: for.inc.peel5:
-; CHECK-NEXT: [[INC_PEEL6:%.*]] = add nsw i32 [[INC_PEEL]], 1
-; CHECK-NEXT: [[CMP_PEEL7:%.*]] = icmp slt i32 [[INC_PEEL6]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL7]], label [[FOR_BODY_PEEL_NEXT1:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next1:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL9:%.*]]
-; CHECK: for.body.peel9:
-; CHECK-NEXT: [[CMP1_PEEL10:%.*]] = icmp ugt i32 [[INC_PEEL6]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL10]], label [[IF_THEN_PEEL11:%.*]], label [[FOR_INC_PEEL12:%.*]]
-; CHECK: if.then.peel11:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL12]]
-; CHECK: for.inc.peel12:
-; CHECK-NEXT: [[INC_PEEL13:%.*]] = add nsw i32 [[INC_PEEL6]], 1
-; CHECK-NEXT: [[CMP_PEEL14:%.*]] = icmp slt i32 [[INC_PEEL13]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL14]], label [[FOR_BODY_PEEL_NEXT8:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next8:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL16:%.*]]
-; CHECK: for.body.peel16:
-; CHECK-NEXT: [[CMP1_PEEL17:%.*]] = icmp ugt i32 [[INC_PEEL13]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL17]], label [[IF_THEN_PEEL18:%.*]], label [[FOR_INC_PEEL19:%.*]]
-; CHECK: if.then.peel18:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL19]]
-; CHECK: for.inc.peel19:
-; CHECK-NEXT: [[INC_PEEL20:%.*]] = add nsw i32 [[INC_PEEL13]], 1
-; CHECK-NEXT: [[CMP_PEEL21:%.*]] = icmp slt i32 [[INC_PEEL20]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL21]], label [[FOR_BODY_PEEL_NEXT15:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next15:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL23:%.*]]
-; CHECK: for.body.peel23:
-; CHECK-NEXT: [[CMP1_PEEL24:%.*]] = icmp ugt i32 [[INC_PEEL20]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL24]], label [[IF_THEN_PEEL25:%.*]], label [[FOR_INC_PEEL26:%.*]]
-; CHECK: if.then.peel25:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL26]]
-; CHECK: for.inc.peel26:
-; CHECK-NEXT: [[INC_PEEL27:%.*]] = add nsw i32 [[INC_PEEL20]], 1
-; CHECK-NEXT: [[CMP_PEEL28:%.*]] = icmp slt i32 [[INC_PEEL27]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL28]], label [[FOR_BODY_PEEL_NEXT22:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next22:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL30:%.*]]
-; CHECK: for.body.peel30:
-; CHECK-NEXT: [[CMP1_PEEL31:%.*]] = icmp ugt i32 [[INC_PEEL27]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL31]], label [[IF_THEN_PEEL32:%.*]], label [[FOR_INC_PEEL33:%.*]]
-; CHECK: if.then.peel32:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL33]]
-; CHECK: for.inc.peel33:
-; CHECK-NEXT: [[INC_PEEL34:%.*]] = add nsw i32 [[INC_PEEL27]], 1
-; CHECK-NEXT: [[CMP_PEEL35:%.*]] = icmp slt i32 [[INC_PEEL34]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL35]], label [[FOR_BODY_PEEL_NEXT29:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next29:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL37:%.*]]
-; CHECK: for.body.peel37:
-; CHECK-NEXT: [[CMP1_PEEL38:%.*]] = icmp ugt i32 [[INC_PEEL34]], 9999
-; CHECK-NEXT: br i1 [[CMP1_PEEL38]], label [[IF_THEN_PEEL39:%.*]], label [[FOR_INC_PEEL40:%.*]]
-; CHECK: if.then.peel39:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL40]]
-; CHECK: for.inc.peel40:
-; CHECK-NEXT: [[INC_PEEL41:%.*]] = add nsw i32 [[INC_PEEL34]], 1
-; CHECK-NEXT: [[CMP_PEEL42:%.*]] = icmp slt i32 [[INC_PEEL41]], [[K]]
-; CHECK-NEXT: br i1 [[CMP_PEEL42]], label [[FOR_BODY_PEEL_NEXT36:%.*]], label [[FOR_END]]
-; CHECK: for.body.peel.next36:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL_NEXT43:%.*]]
-; CHECK: for.body.peel.next43:
-; CHECK-NEXT: br label [[FOR_BODY_LR_PH_PEEL_NEWPH:%.*]]
-; CHECK: for.body.lr.ph.peel.newph:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
-; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ [[INC_PEEL41]], [[FOR_BODY_LR_PH_PEEL_NEWPH]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[FOR_BODY_LR_PH:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt i32 [[I_05]], 9999
; CHECK-NEXT: br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[FOR_INC]]
; CHECK: if.then:
; CHECK-NEXT: call void @f1()
; CHECK-NEXT: br label [[FOR_INC]]
; CHECK: for.inc:
-; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I_05]], 1
-; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K]]
-; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop !4
-; CHECK: for.end.loopexit:
-; CHECK-NEXT: br label [[FOR_END]]
+; CHECK-NEXT: [[INC]] = add nsw i32 [[I_05]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K:%.*]]
+; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -535,36 +444,18 @@ for.end:
ret void
}
+; In this test, the condition involves 2 AddRecs. Without evaluating both
+; AddRecs, we cannot prove that the condition becomes known in the loop body
+; after peeling.
define void @test6(i32 %k) {
; CHECK-LABEL: @test6(
; CHECK-NEXT: entry:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL_BEGIN:%.*]]
-; CHECK: for.body.peel.begin:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL:%.*]]
-; CHECK: for.body.peel:
-; CHECK-NEXT: [[CMP1_PEEL:%.*]] = icmp ult i32 0, 4
-; CHECK-NEXT: br i1 [[CMP1_PEEL]], label [[IF_THEN_PEEL:%.*]], label [[IF_ELSE_PEEL:%.*]]
-; CHECK: if.else.peel:
-; CHECK-NEXT: call void @f2()
-; CHECK-NEXT: br label [[FOR_INC_PEEL:%.*]]
-; CHECK: if.then.peel:
-; CHECK-NEXT: call void @f1()
-; CHECK-NEXT: br label [[FOR_INC_PEEL]]
-; CHECK: for.inc.peel:
-; CHECK-NEXT: [[INC_PEEL:%.*]] = add nsw i32 0, 2
-; CHECK-NEXT: [[J_INC_PEEL:%.*]] = add nsw i32 4, 1
-; CHECK-NEXT: [[CMP_PEEL:%.*]] = icmp slt i32 [[INC_PEEL]], [[K:%.*]]
-; CHECK-NEXT: br i1 [[CMP_PEEL]], label [[FOR_BODY_PEEL_NEXT:%.*]], label [[FOR_END:%.*]]
-; CHECK: for.body.peel.next:
-; CHECK-NEXT: br label [[FOR_BODY_PEEL_NEXT1:%.*]]
-; CHECK: for.body.peel.next1:
-; CHECK-NEXT: br label [[ENTRY_PEEL_NEWPH:%.*]]
-; CHECK: entry.peel.newph:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
-; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ [[INC_PEEL]], [[ENTRY_PEEL_NEWPH]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
-; CHECK-NEXT: [[J:%.*]] = phi i32 [ [[INC_PEEL]], [[ENTRY_PEEL_NEWPH]] ], [ [[INC]], [[FOR_INC]] ]
-; CHECK-NEXT: br i1 false, label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT: [[J:%.*]] = phi i32 [ 4, [[ENTRY]] ], [ [[J_INC:%.*]], [[FOR_INC]] ]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[I_05]], [[J]]
+; CHECK-NEXT: br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
; CHECK: if.then:
; CHECK-NEXT: call void @f1()
; CHECK-NEXT: br label [[FOR_INC]]
@@ -572,11 +463,10 @@ define void @test6(i32 %k) {
; CHECK-NEXT: call void @f2()
; CHECK-NEXT: br label [[FOR_INC]]
; CHECK: for.inc:
-; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I_05]], 2
-; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K]]
-; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop !5
-; CHECK: for.end.loopexit:
-; CHECK-NEXT: br label [[FOR_END]]
+; CHECK-NEXT: [[INC]] = add nsw i32 [[I_05]], 2
+; CHECK-NEXT: [[J_INC]] = add nsw i32 [[J]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K:%.*]]
+; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -585,7 +475,7 @@ entry:
for.body:
%i.05 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
- %j = phi i32 [ 4, %entry ], [ %inc, %for.inc ]
+ %j = phi i32 [ 4, %entry ], [ %j.inc, %for.inc ]
%cmp1 = icmp ult i32 %i.05, %j
br i1 %cmp1, label %if.then, label %if.else
@@ -603,6 +493,129 @@ for.inc:
%cmp = icmp slt i32 %inc, %k
br i1 %cmp, label %for.body, label %for.end
+for.end:
+ ret void
+}
+
+define void @test7(i32 %k) {
+; FIXME: Could simplify loop body by peeling one additional iteration after
+; i != 3 becomes false
+; CHECK-LABEL: @test7(
+; CHECK-NEXT: for.body.lr.ph:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[FOR_BODY_LR_PH:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[I_05]], 3
+; CHECK-NEXT: br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[FOR_INC]]
+; CHECK: if.then:
+; CHECK-NEXT: call void @f1()
+; CHECK-NEXT: br label [[FOR_INC]]
+; CHECK: for.inc:
+; CHECK-NEXT: [[INC]] = add nsw i32 [[I_05]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K:%.*]]
+; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret void
+;
+for.body.lr.ph:
+ br label %for.body
+
+for.body:
+ %i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
+ %cmp1 = icmp ne i32 %i.05, 3
+ br i1 %cmp1, label %if.then, label %for.inc
+
+if.then:
+ call void @f1()
+ br label %for.inc
+
+for.inc:
+ %inc = add nsw i32 %i.05, 1
+ %cmp = icmp slt i32 %inc, %k
+ br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+ ret void
+}
+
+define void @test8(i32 %k) {
+; FIXME: Could simplify loop body by peeling one additional iteration after
+; i == 3 becomes true.
+; CHECK-LABEL: @test8(
+; CHECK-NEXT: for.body.lr.ph:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[FOR_BODY_LR_PH:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[I_05]], 3
+; CHECK-NEXT: br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[FOR_INC]]
+; CHECK: if.then:
+; CHECK-NEXT: call void @f1()
+; CHECK-NEXT: br label [[FOR_INC]]
+; CHECK: for.inc:
+; CHECK-NEXT: [[INC]] = add nsw i32 [[I_05]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K:%.*]]
+; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret void
+;
+for.body.lr.ph:
+ br label %for.body
+
+for.body:
+ %i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
+ %cmp1 = icmp eq i32 %i.05, 3
+ br i1 %cmp1, label %if.then, label %for.inc
+
+if.then:
+ call void @f1()
+ br label %for.inc
+
+for.inc:
+ %inc = add nsw i32 %i.05, 1
+ %cmp = icmp slt i32 %inc, %k
+ br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+ ret void
+}
+
+; Comparison with non-monotonic predicate due to possible wrapping, loop
+; body cannot be simplified.
+define void @test9(i32 %k) {
+; CHECK-LABEL: @test9(
+; CHECK-NEXT: for.body.lr.ph:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[FOR_BODY_LR_PH:%.*]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[I_05]], 3
+; CHECK-NEXT: br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[FOR_INC]]
+; CHECK: if.then:
+; CHECK-NEXT: call void @f1()
+; CHECK-NEXT: br label [[FOR_INC]]
+; CHECK: for.inc:
+; CHECK-NEXT: [[INC]] = add i32 [[I_05]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[INC]], [[K:%.*]]
+; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret void
+;
+for.body.lr.ph:
+ br label %for.body
+
+for.body:
+ %i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
+ %cmp1 = icmp slt i32 %i.05, 3
+ br i1 %cmp1, label %if.then, label %for.inc
+
+if.then:
+ call void @f1()
+ br label %for.inc
+
+for.inc:
+ %inc = add i32 %i.05, 1
+ %cmp = icmp slt i32 %inc, %k
+ br i1 %cmp, label %for.body, label %for.end
+
for.end:
ret void
}
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