[ScalarEvolutionExpander] Properly insert no-op casts + EH Pads

We want to insert no-op casts as close as possible to the def.  This is
tricky when the cast is of a PHI node and the BasicBlocks between the
def and the use cannot hold any instructions.  Iteratively walk EH pads
until we hit a non-EH pad.

This fixes PR25326.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251393 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ScalarEvolutionExpander.cpp

@@ -86,6 +86,41 @@ Value *SCEVExpander::ReuseOrCreateCast(Value *V, Type *Ty,
   return Ret;
 }
 
+static BasicBlock::iterator findInsertPointAfter(Instruction *I,
+                                                 DominatorTree &DT,
+                                                 BasicBlock *MustDominate) {
+  BasicBlock::iterator IP = ++I->getIterator();
+  if (auto *II = dyn_cast<InvokeInst>(I))
+    IP = II->getNormalDest()->begin();
+  if (auto *CPI = dyn_cast<CatchPadInst>(I))
+    IP = CPI->getNormalDest()->begin();
+
+  while (isa<PHINode>(IP))
+    ++IP;
+
+  while (IP->isEHPad()) {
+    if (isa<LandingPadInst>(IP) || isa<CleanupPadInst>(IP)) {
+      ++IP;
+    } else if (auto *TPI = dyn_cast<TerminatePadInst>(IP)) {
+      IP = TPI->getUnwindDest()->getFirstNonPHI();
+    } else if (auto *CEPI = dyn_cast<CatchEndPadInst>(IP)) {
+      IP = CEPI->getUnwindDest()->getFirstNonPHI();
+    } else if (auto *CEPI = dyn_cast<CleanupEndPadInst>(IP)) {
+      IP = CEPI->getUnwindDest()->getFirstNonPHI();
+    } else if (auto *CPI = dyn_cast<CatchPadInst>(IP)) {
+      BasicBlock *NormalDest = CPI->getNormalDest();
+      if (NormalDest == MustDominate || DT.dominates(NormalDest, MustDominate))
+        IP = NormalDest->getFirstNonPHI();
+      else
+        IP = CPI->getUnwindDest()->getFirstNonPHI();
+    } else {
+      llvm_unreachable("unexpected eh pad!");
+    }
+  }
+
+  return IP;
+}
+
 /// InsertNoopCastOfTo - Insert a cast of V to the specified type,
 /// which must be possible with a noop cast, doing what we can to share
 /// the casts.
@@ -135,21 +170,15 @@ Value *SCEVExpander::InsertNoopCastOfTo(Value *V, Type *Ty) {
     while ((isa<BitCastInst>(IP) &&
             isa<Argument>(cast<BitCastInst>(IP)->getOperand(0)) &&
             cast<BitCastInst>(IP)->getOperand(0) != A) ||
-           isa<DbgInfoIntrinsic>(IP) ||
+           isa<DbgInfoIntrinsic>(IP))
-           isa<LandingPadInst>(IP))
       ++IP;
     return ReuseOrCreateCast(A, Ty, Op, IP);
   }
 
   // Cast the instruction immediately after the instruction.
   Instruction *I = cast<Instruction>(V);
-  BasicBlock::iterator IP = ++I->getIterator();
+  BasicBlock::iterator IP =
-  if (InvokeInst *II = dyn_cast<InvokeInst>(I))
+      findInsertPointAfter(I, SE.DT, Builder.GetInsertBlock());
-    IP = II->getNormalDest()->begin();
-  if (CatchPadInst *CPI = dyn_cast<CatchPadInst>(I))
-    IP = CPI->getNormalDest()->begin();
-  while (isa<PHINode>(IP) || isa<LandingPadInst>(IP))
-    ++IP;
   return ReuseOrCreateCast(I, Ty, Op, IP);
 }
 
@@ -1394,12 +1423,8 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
       NewOps[i] = SE.getAnyExtendExpr(S->op_begin()[i], CanonicalIV->getType());
     Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop(),
                                        S->getNoWrapFlags(SCEV::FlagNW)));
-    BasicBlock::iterator NewInsertPt =
+    BasicBlock::iterator NewInsertPt = findInsertPointAfter(
-      std::next(BasicBlock::iterator(cast<Instruction>(V)));
+        cast<Instruction>(V), SE.DT, Builder.GetInsertBlock());
-    BuilderType::InsertPointGuard Guard(Builder);
-    while (isa<PHINode>(NewInsertPt) || isa<DbgInfoIntrinsic>(NewInsertPt) ||
-           isa<LandingPadInst>(NewInsertPt))
-      ++NewInsertPt;
     V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), nullptr,
                       &*NewInsertPt);
     return V;

test/Transforms/LoopStrengthReduce/funclet.ll

@@ -0,0 +1,148 @@
+; RUN: opt < %s -loop-reduce -S | FileCheck %s
+
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc"
+
+declare i32 @_except_handler3(...)
+
+declare void @reserve()
+
+define void @f() personality i32 (...)* @_except_handler3 {
+entry:
+  br label %throw
+
+throw:                                            ; preds = %throw, %entry
+  %tmp96 = getelementptr inbounds i8, i8* undef, i32 1
+  invoke void @reserve()
+          to label %throw unwind label %pad
+
+pad:                                              ; preds = %throw
+  %phi2 = phi i8* [ %tmp96, %throw ]
+  terminatepad [] unwind label %blah
+
+blah:
+  catchpad [] to label %unreachable unwind label %blah3
+
+unreachable:
+  unreachable
+
+blah3:
+  catchendpad unwind label %blah2
+
+blah2:
+  %cleanuppadi4.i.i.i = cleanuppad []
+  br label %loop_body
+
+loop_body:                                        ; preds = %iter, %pad
+  %tmp99 = phi i8* [ %tmp101, %iter ], [ %phi2, %blah2 ]
+  %tmp100 = icmp eq i8* %tmp99, undef
+  br i1 %tmp100, label %unwind_out, label %iter
+
+iter:                                             ; preds = %loop_body
+  %tmp101 = getelementptr inbounds i8, i8* %tmp99, i32 1
+  br i1 undef, label %unwind_out, label %loop_body
+
+unwind_out:                                       ; preds = %iter, %loop_body
+  cleanupret %cleanuppadi4.i.i.i unwind to caller
+}
+
+; CHECK-LABEL: define void @f(
+; CHECK: cleanuppad []
+; CHECK-NEXT: ptrtoint i8* %phi2 to i32
+
+define void @g() personality i32 (...)* @_except_handler3 {
+entry:
+  br label %throw
+
+throw:                                            ; preds = %throw, %entry
+  %tmp96 = getelementptr inbounds i8, i8* undef, i32 1
+  invoke void @reserve()
+          to label %throw unwind label %pad
+
+pad:
+  %phi2 = phi i8* [ %tmp96, %throw ]
+  catchpad [] to label %unreachable unwind label %blah
+
+unreachable:
+  unreachable
+
+blah:
+  %catchpad = catchpad [] to label %loop_body unwind label %blah3
+
+
+blah3:
+  catchendpad unwind to caller ;label %blah2
+
+unwind_out:
+  catchret %catchpad to label %leave
+
+leave:
+  ret void
+
+loop_body:                                        ; preds = %iter, %pad
+  %tmp99 = phi i8* [ %tmp101, %iter ], [ %phi2, %blah ]
+  %tmp100 = icmp eq i8* %tmp99, undef
+  br i1 %tmp100, label %unwind_out, label %iter
+
+iter:                                             ; preds = %loop_body
+  %tmp101 = getelementptr inbounds i8, i8* %tmp99, i32 1
+  br i1 undef, label %unwind_out, label %loop_body
+}
+
+; CHECK-LABEL: define void @g(
+; CHECK: blah:
+; CHECK-NEXT: catchpad []
+; CHECK-NEXT: to label %loop_body.preheader
+
+; CHECK: loop_body.preheader:
+; CHECK-NEXT: ptrtoint i8* %phi2 to i32
+
+
+define void @h() personality i32 (...)* @_except_handler3 {
+entry:
+  br label %throw
+
+throw:                                            ; preds = %throw, %entry
+  %tmp96 = getelementptr inbounds i8, i8* undef, i32 1
+  invoke void @reserve()
+          to label %throw unwind label %pad
+
+pad:
+  catchpad [] to label %unreachable unwind label %blug
+
+unreachable:
+  unreachable
+
+blug:
+  %phi2 = phi i8* [ %tmp96, %pad ]
+  %catchpad = catchpad [] to label %blah2 unwind label %blah3
+
+blah2:
+  br label %loop_body
+
+blah3:
+  catchendpad unwind to caller ;label %blah2
+
+unwind_out:
+  catchret %catchpad to label %leave
+
+leave:
+  ret void
+
+loop_body:                                        ; preds = %iter, %pad
+  %tmp99 = phi i8* [ %tmp101, %iter ], [ %phi2, %blah2 ]
+  %tmp100 = icmp eq i8* %tmp99, undef
+  br i1 %tmp100, label %unwind_out, label %iter
+
+iter:                                             ; preds = %loop_body
+  %tmp101 = getelementptr inbounds i8, i8* %tmp99, i32 1
+  br i1 undef, label %unwind_out, label %loop_body
+}
+
+; CHECK-LABEL: define void @h(
+; CHECK: blug:
+; CHECK: catchpad []
+; CHECK-NEXT: to label %blah2
+
+; CHECK: blah2:
+; CHECK-NEXT: ptrtoint i8* %phi2 to i32