--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -O1 -S < %s | FileCheck %s --check-prefix=OLDPM
+; RUN: opt -passes='default<O1>' -S < %s | FileCheck %s --check-prefix=NEWPM
+
+; Don't simplify unconditional branches from empty blocks in simplifyCFG
+; until late in the pipeline because it can destroy canonical loop structure.
+
+; FIXME: The new pass manager is not limiting simplifycfg at any point in the pipeline,
+; so it performs a transformation before loop optimizations that is avoided in the old PM.
+
+define i1 @PR33605(i32 %a, i32 %b, i32* %c) {
+; OLDPM-LABEL: @PR33605(
+; OLDPM-NEXT: for.body:
+; OLDPM-NEXT: [[OR:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
+; OLDPM-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[C:%.*]], i64 1
+; OLDPM-NEXT: [[TMP0:%.*]] = load i32, i32* [[ARRAYIDX]], align 4
+; OLDPM-NEXT: [[CMP:%.*]] = icmp eq i32 [[OR]], [[TMP0]]
+; OLDPM-NEXT: br i1 [[CMP]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
+; OLDPM: if.then:
+; OLDPM-NEXT: store i32 [[OR]], i32* [[ARRAYIDX]], align 4
+; OLDPM-NEXT: tail call void @foo()
+; OLDPM-NEXT: br label [[IF_END]]
+; OLDPM: if.end:
+; OLDPM-NEXT: [[CHANGED_1_OFF0:%.*]] = phi i1 [ true, [[IF_THEN]] ], [ false, [[FOR_BODY:%.*]] ]
+; OLDPM-NEXT: [[TMP1:%.*]] = load i32, i32* [[C]], align 4
+; OLDPM-NEXT: [[CMP_1:%.*]] = icmp eq i32 [[OR]], [[TMP1]]
+; OLDPM-NEXT: br i1 [[CMP_1]], label [[IF_END_1:%.*]], label [[IF_THEN_1:%.*]]
+; OLDPM: if.then.1:
+; OLDPM-NEXT: store i32 [[OR]], i32* [[C]], align 4
+; OLDPM-NEXT: tail call void @foo()
+; OLDPM-NEXT: br label [[IF_END_1]]
+; OLDPM: if.end.1:
+; OLDPM-NEXT: [[CHANGED_1_OFF0_1:%.*]] = phi i1 [ true, [[IF_THEN_1]] ], [ [[CHANGED_1_OFF0]], [[IF_END]] ]
+; OLDPM-NEXT: ret i1 [[CHANGED_1_OFF0_1]]
+;
+; NEWPM-LABEL: @PR33605(
+; NEWPM-NEXT: entry:
+; NEWPM-NEXT: [[OR:%.*]] = or i32 [[B:%.*]], [[A:%.*]]
+; NEWPM-NEXT: br label [[FOR_COND_OUTER:%.*]]
+; NEWPM: for.cond.outer:
+; NEWPM-NEXT: [[I_0_PH:%.*]] = phi i32 [ [[DEC:%.*]], [[IF_THEN:%.*]] ], [ 2, [[ENTRY:%.*]] ]
+; NEWPM-NEXT: [[CHANGED_0_OFF0_PH:%.*]] = phi i1 [ true, [[IF_THEN]] ], [ false, [[ENTRY]] ]
+; NEWPM-NEXT: br label [[FOR_COND:%.*]]
+; NEWPM: for.cond:
+; NEWPM-NEXT: [[I_0:%.*]] = phi i32 [ [[DEC]], [[FOR_BODY:%.*]] ], [ [[I_0_PH]], [[FOR_COND_OUTER]] ]
+; NEWPM-NEXT: [[DEC]] = add nsw i32 [[I_0]], -1
+; NEWPM-NEXT: [[TOBOOL:%.*]] = icmp eq i32 [[I_0]], 0
+; NEWPM-NEXT: br i1 [[TOBOOL]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]]
+; NEWPM: for.cond.cleanup:
+; NEWPM-NEXT: ret i1 [[CHANGED_0_OFF0_PH]]
+; NEWPM: for.body:
+; NEWPM-NEXT: [[IDXPROM:%.*]] = sext i32 [[DEC]] to i64
+; NEWPM-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[C:%.*]], i64 [[IDXPROM]]
+; NEWPM-NEXT: [[TMP0:%.*]] = load i32, i32* [[ARRAYIDX]], align 4
+; NEWPM-NEXT: [[CMP:%.*]] = icmp eq i32 [[OR]], [[TMP0]]
+; NEWPM-NEXT: br i1 [[CMP]], label [[FOR_COND]], label [[IF_THEN]]
+; NEWPM: if.then:
+; NEWPM-NEXT: store i32 [[OR]], i32* [[ARRAYIDX]], align 4
+; NEWPM-NEXT: tail call void @foo()
+; NEWPM-NEXT: br label [[FOR_COND_OUTER]]
+;
+entry:
+ br label %for.cond
+
+for.cond:
+ %i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
+ %changed.0.off0 = phi i1 [ false, %entry ], [ %changed.1.off0, %if.end ]
+ %dec = add nsw i32 %i.0, -1
+ %tobool = icmp eq i32 %i.0, 0
+ br i1 %tobool, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ %changed.0.off0.lcssa = phi i1 [ %changed.0.off0, %for.cond ]
+ ret i1 %changed.0.off0.lcssa
+
+for.body:
+ %or = or i32 %a, %b
+ %idxprom = sext i32 %dec to i64
+ %arrayidx = getelementptr inbounds i32, i32* %c, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %cmp = icmp eq i32 %or, %0
+ br i1 %cmp, label %if.end, label %if.then
+
+if.then:
+ store i32 %or, i32* %arrayidx, align 4
+ call void @foo()
+ br label %if.end
+
+if.end:
+ %changed.1.off0 = phi i1 [ true, %if.then ], [ %changed.0.off0, %for.body ]
+ br label %for.cond
+}
+
+declare void @foo()
+