LoopRotate: Also rotate loops with multiple exits.

The old PHI updating code in loop-rotate was replaced with SSAUpdater a while
ago, it has no problems with comples PHIs. What had to be fixed is detecting
whether a loop was already rotated and updating dominators when multiple exits
were present.

This change increases overall code size a bit, mostly due to additional loop
unrolling opportunities. Passes test-suite and selfhost with -verify-dom-info.
Fixes PR7447.

Thanks to Andy for the input on the domtree updating code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162912 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 200 insertions, 0 deletions

diff --git a/test/Transforms/LoopRotate/multiple-exits.ll b/test/Transforms/LoopRotate/multiple-exits.ll
new file mode 100644
index 0000000000..4568678c3d
--- /dev/null
+++ b/test/Transforms/LoopRotate/multiple-exits.ll
@@ -0,0 +1,200 @@
+; RUN: opt -S -loop-rotate < %s -verify-loop-info -verify-dom-info | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+; PR7447
+define i32 @test1([100 x i32]* nocapture %a) nounwind readonly {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.cond1, %entry
+  %sum.0 = phi i32 [ 0, %entry ], [ %sum.1, %for.cond1 ]
+  %i.0 = phi i1 [ true, %entry ], [ false, %for.cond1 ]
+  br i1 %i.0, label %for.cond1, label %return
+
+for.cond1:                                        ; preds = %for.cond, %land.rhs
+  %sum.1 = phi i32 [ %add, %land.rhs ], [ %sum.0, %for.cond ]
+  %i.1 = phi i32 [ %inc, %land.rhs ], [ 0, %for.cond ]
+  %cmp2 = icmp ult i32 %i.1, 100
+  br i1 %cmp2, label %land.rhs, label %for.cond
+
+land.rhs:                                         ; preds = %for.cond1
+  %conv = zext i32 %i.1 to i64
+  %arrayidx = getelementptr inbounds [100 x i32]* %a, i64 0, i64 %conv
+  %0 = load i32* %arrayidx, align 4
+  %add = add i32 %0, %sum.1
+  %cmp4 = icmp ugt i32 %add, 1000
+  %inc = add i32 %i.1, 1
+  br i1 %cmp4, label %return, label %for.cond1
+
+return:                                           ; preds = %for.cond, %land.rhs
+  %retval.0 = phi i32 [ 1000, %land.rhs ], [ %sum.0, %for.cond ]
+  ret i32 %retval.0
+
+; CHECK: @test1
+; CHECK: for.cond1.preheader:
+; CHECK: %sum.04 = phi i32 [ 0, %entry ], [ %sum.1.lcssa, %for.cond.loopexit ]
+; CHECK: br label %for.cond1
+
+; CHECK: for.cond1:
+; CHECK: %sum.1 = phi i32 [ %add, %land.rhs ], [ %sum.04, %for.cond1.preheader ]
+; CHECK: %i.1 = phi i32 [ %inc, %land.rhs ], [ 0, %for.cond1.preheader ]
+; CHECK: %cmp2 = icmp ult i32 %i.1, 100
+; CHECK: br i1 %cmp2, label %land.rhs, label %for.cond.loopexit
+}
+
+define void @test2(i32 %x) nounwind {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %if.end, %entry
+  %i.0 = phi i32 [ 0, %entry ], [ %inc, %if.end ]
+  %cmp = icmp eq i32 %i.0, %x
+  br i1 %cmp, label %return.loopexit, label %for.body
+
+for.body:                                         ; preds = %for.cond
+  %call = tail call i32 @foo(i32 %i.0) nounwind
+  %tobool = icmp eq i32 %call, 0
+  br i1 %tobool, label %if.end, label %a
+
+if.end:                                           ; preds = %for.body
+  %call1 = tail call i32 @foo(i32 42) nounwind
+  %inc = add i32 %i.0, 1
+  br label %for.cond
+
+a:                                                ; preds = %for.body
+  %call2 = tail call i32 @bar(i32 1) nounwind
+  br label %return
+
+return.loopexit:                                  ; preds = %for.cond
+  br label %return
+
+return:                                           ; preds = %return.loopexit, %a
+  ret void
+
+; CHECK: @test2
+; CHECK: if.end:
+; CHECK: %inc = add i32 %i.02, 1
+; CHECK: %cmp = icmp eq i32 %inc, %x
+; CHECK: br i1 %cmp, label %for.cond.return.loopexit_crit_edge, label %for.body
+}
+
+declare i32 @foo(i32)
+
+declare i32 @bar(i32)
+
+@_ZTIi = external constant i8*
+
+; Verify dominators.
+define void @test3(i32 %x) {
+entry:
+  %cmp2 = icmp eq i32 0, %x
+  br i1 %cmp2, label %try.cont.loopexit, label %for.body.lr.ph
+
+for.body.lr.ph:                                   ; preds = %entry
+  br label %for.body
+
+for.body:                                         ; preds = %for.body.lr.ph, %for.inc
+  %i.03 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
+  invoke void @_Z3fooi(i32 %i.03)
+          to label %for.inc unwind label %lpad
+
+for.inc:                                          ; preds = %for.body
+  %inc = add i32 %i.03, 1
+  %cmp = icmp eq i32 %inc, %x
+  br i1 %cmp, label %for.cond.try.cont.loopexit_crit_edge, label %for.body
+
+lpad:                                             ; preds = %for.body
+  %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+  %1 = extractvalue { i8*, i32 } %0, 0
+  %2 = extractvalue { i8*, i32 } %0, 1
+  %3 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*)) nounwind
+  %matches = icmp eq i32 %2, %3
+  br i1 %matches, label %catch, label %eh.resume
+
+catch:                                            ; preds = %lpad
+  %4 = tail call i8* @__cxa_begin_catch(i8* %1) nounwind
+  br i1 true, label %invoke.cont2.loopexit, label %for.body.i.lr.ph
+
+for.body.i.lr.ph:                                 ; preds = %catch
+  br label %for.body.i
+
+for.body.i:                                       ; preds = %for.body.i.lr.ph, %for.inc.i
+  %i.0.i1 = phi i32 [ 0, %for.body.i.lr.ph ], [ %inc.i, %for.inc.i ]
+  invoke void @_Z3fooi(i32 %i.0.i1)
+          to label %for.inc.i unwind label %lpad.i
+
+for.inc.i:                                        ; preds = %for.body.i
+  %inc.i = add i32 %i.0.i1, 1
+  %cmp.i = icmp eq i32 %inc.i, 0
+  br i1 %cmp.i, label %for.cond.i.invoke.cont2.loopexit_crit_edge, label %for.body.i
+
+lpad.i:                                           ; preds = %for.body.i
+  %5 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+  %6 = extractvalue { i8*, i32 } %5, 0
+  %7 = extractvalue { i8*, i32 } %5, 1
+  %matches.i = icmp eq i32 %7, %3
+  br i1 %matches.i, label %catch.i, label %lpad1.body
+
+catch.i:                                          ; preds = %lpad.i
+  %8 = tail call i8* @__cxa_begin_catch(i8* %6) nounwind
+  invoke void @_Z3barj(i32 0)
+          to label %invoke.cont2.i unwind label %lpad1.i
+
+invoke.cont2.i:                                   ; preds = %catch.i
+  tail call void @__cxa_end_catch() nounwind
+  br label %invoke.cont2
+
+lpad1.i:                                          ; preds = %catch.i
+  %9 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  %10 = extractvalue { i8*, i32 } %9, 0
+  %11 = extractvalue { i8*, i32 } %9, 1
+  tail call void @__cxa_end_catch() nounwind
+  br label %lpad1.body
+
+for.cond.i.invoke.cont2.loopexit_crit_edge:       ; preds = %for.inc.i
+  br label %invoke.cont2.loopexit
+
+invoke.cont2.loopexit:                            ; preds = %for.cond.i.invoke.cont2.loopexit_crit_edge, %catch
+  br label %invoke.cont2
+
+invoke.cont2:                                     ; preds = %invoke.cont2.loopexit, %invoke.cont2.i
+  tail call void @__cxa_end_catch() nounwind
+  br label %try.cont
+
+for.cond.try.cont.loopexit_crit_edge:             ; preds = %for.inc
+  br label %try.cont.loopexit
+
+try.cont.loopexit:                                ; preds = %for.cond.try.cont.loopexit_crit_edge, %entry
+  br label %try.cont
+
+try.cont:                                         ; preds = %try.cont.loopexit, %invoke.cont2
+  ret void
+
+lpad1.body:                                       ; preds = %lpad1.i, %lpad.i
+  %exn.slot.0.i = phi i8* [ %10, %lpad1.i ], [ %6, %lpad.i ]
+  %ehselector.slot.0.i = phi i32 [ %11, %lpad1.i ], [ %7, %lpad.i ]
+  tail call void @__cxa_end_catch() nounwind
+  br label %eh.resume
+
+eh.resume:                                        ; preds = %lpad1.body, %lpad
+  %exn.slot.0 = phi i8* [ %exn.slot.0.i, %lpad1.body ], [ %1, %lpad ]
+  %ehselector.slot.0 = phi i32 [ %ehselector.slot.0.i, %lpad1.body ], [ %2, %lpad ]
+  %lpad.val = insertvalue { i8*, i32 } undef, i8* %exn.slot.0, 0
+  %lpad.val5 = insertvalue { i8*, i32 } %lpad.val, i32 %ehselector.slot.0, 1
+  resume { i8*, i32 } %lpad.val5
+}
+
+declare void @_Z3fooi(i32)
+
+declare i32 @__gxx_personality_v0(...)
+
+declare i32 @llvm.eh.typeid.for(i8*) nounwind readnone
+
+declare i8* @__cxa_begin_catch(i8*)
+
+declare void @__cxa_end_catch()