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[LoopBoundSplit] Check if latch is operand of PHI induction variable #167227

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[LoopBoundSplit] Check if latch is operand of PHI induction variable #167227

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4 changes: 3 additions & 1 deletion llvm/lib/Transforms/Scalar/LoopBoundSplit.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -72,7 +72,9 @@ static void analyzeICmp(ScalarEvolution &SE, ICmpInst *ICmp,
// value from backedge.
if (Cond.AddRecSCEV && isa<PHINode>(Cond.AddRecValue)) {
PHINode *PN = cast<PHINode>(Cond.AddRecValue);
Cond.NonPHIAddRecValue = PN->getIncomingValueForBlock(L.getLoopLatch());
int Idx = PN->getBasicBlockIndex(L.getLoopLatch());
if (Idx >= 0)
Cond.NonPHIAddRecValue = PN->getIncomingValue(Idx);
}
}
}
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83 changes: 83 additions & 0 deletions llvm/test/Transforms/LoopBoundSplit/loop-bound-split.ll
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Expand Up @@ -955,3 +955,86 @@ exit:
}

declare i64 @llvm.umax.i64(i64, i64)

define void @outer_iv_used_within_inner_icmp(i32 %k) {
; CHECK-LABEL: @outer_iv_used_within_inner_icmp(
; CHECK-NEXT: for.body.lr.ph:
; CHECK-NEXT: [[SMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[K:%.*]], i32 1)
; CHECK-NEXT: [[TMP0:%.*]] = add nsw i32 [[SMAX]], -1
; CHECK-NEXT: [[NEW_BOUND:%.*]] = call i32 @llvm.smin.i32(i32 [[TMP0]], i32 2)
; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
; CHECK: outer.header:
; CHECK-NEXT: [[J:%.*]] = phi i32 [ 0, [[FOR_BODY_LR_PH:%.*]] ], [ [[J_INC:%.*]], [[OUTER_INC:%.*]] ]
; CHECK-NEXT: br label [[OUTER_HEADER_SPLIT:%.*]]
; CHECK: outer.header.split:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[I_05:%.*]] = phi i32 [ 0, [[OUTER_HEADER_SPLIT]] ], [ [[INC:%.*]], [[FOR_INC:%.*]] ]
; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[J]], 2
; CHECK-NEXT: br i1 true, label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[FOR_INC]]
; CHECK: if.else:
; 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]], [[NEW_BOUND]]
; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[OUTER_HEADER_SPLIT_SPLIT:%.*]]
; CHECK: outer.header.split.split:
; CHECK-NEXT: [[I_05_LCSSA:%.*]] = phi i32 [ [[INC]], [[FOR_INC]] ]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ne i32 [[I_05_LCSSA]], [[K]]
; CHECK-NEXT: br i1 [[TMP1]], label [[FOR_BODY_SPLIT_PREHEADER:%.*]], label [[OUTER_INC]]
; CHECK: for.body.split.preheader:
; CHECK-NEXT: br label [[FOR_BODY_SPLIT:%.*]]
; CHECK: for.body.split:
; CHECK-NEXT: [[I_05_SPLIT:%.*]] = phi i32 [ [[INC_SPLIT:%.*]], [[FOR_INC_SPLIT:%.*]] ], [ [[I_05_LCSSA]], [[FOR_BODY_SPLIT_PREHEADER]] ]
; CHECK-NEXT: [[CMP1_SPLIT:%.*]] = icmp ult i32 [[J]], 2
; CHECK-NEXT: br i1 false, label [[IF_THEN_SPLIT:%.*]], label [[IF_ELSE_SPLIT:%.*]]
; CHECK: if.else.split:
; CHECK-NEXT: br label [[FOR_INC_SPLIT]]
; CHECK: if.then.split:
; CHECK-NEXT: br label [[FOR_INC_SPLIT]]
; CHECK: for.inc.split:
; CHECK-NEXT: [[INC_SPLIT]] = add nsw i32 [[I_05_SPLIT]], 1
; CHECK-NEXT: [[CMP_SPLIT:%.*]] = icmp slt i32 [[INC_SPLIT]], [[K]]
; CHECK-NEXT: br i1 [[CMP_SPLIT]], label [[FOR_BODY_SPLIT]], label [[OUTER_INC_LOOPEXIT:%.*]]
; CHECK: outer.inc.loopexit:
; CHECK-NEXT: br label [[OUTER_INC]]
; CHECK: outer.inc:
; CHECK-NEXT: [[J_INC]] = add nsw i32 [[J]], 1
; CHECK-NEXT: [[OUTER_CMP:%.*]] = icmp slt i32 [[J_INC]], [[K]]
; CHECK-NEXT: br i1 [[OUTER_CMP]], label [[OUTER_HEADER]], label [[FOR_END:%.*]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
for.body.lr.ph:
br label %outer.header

outer.header:
%j = phi i32 [ 0, %for.body.lr.ph ], [ %j.inc, %outer.inc ]
br label %for.body

for.body:
%i.05 = phi i32 [ 0, %outer.header ], [ %inc, %for.inc ]
%cmp1 = icmp ult i32 %j, 2
br i1 %cmp1, label %if.then, label %if.else

if.then:
br label %for.inc

if.else:
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 %outer.inc

outer.inc:
%j.inc = add nsw i32 %j, 1
%outer.cmp = icmp slt i32 %j.inc, %k
br i1 %outer.cmp, label %outer.header, label %for.end

for.end:
ret void
}