From 22eeda1bb91c330605f1510b470bc4c51583a206 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 13 Jan 2017 22:24:27 +0000
Subject: [PATCH] [LoopStrengthReduce] Don't bother rewriting PHIs in
 catchswitch blocks

The catchswitch instruction cannot be split, don't bother trying to
rewrite it.

This fixes PR31627.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291966 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopStrengthReduce.cpp  |  6 +-
 test/Transforms/LoopStrengthReduce/pr31627.ll | 58 +++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 test/Transforms/LoopStrengthReduce/pr31627.ll

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index a1561fc0a6c2..01728ae680de 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3163,6 +3163,9 @@ LSRInstance::CollectLoopInvariantFixupsAndFormulae() {
         // Don't bother if the instruction is in a BB which ends in an EHPad.
         if (UseBB->getTerminator()->isEHPad())
           continue;
+        // Don't bother rewriting PHIs in catchswitch blocks.
+        if (isa<CatchSwitchInst>(UserInst->getParent()->getTerminator()))
+          continue;
         // Ignore uses which are part of other SCEV expressions, to avoid
         // analyzing them multiple times.
         if (SE.isSCEVable(UserInst->getType())) {
@@ -4672,7 +4675,8 @@ void LSRInstance::RewriteForPHI(PHINode *PN,
       // is the canonical backedge for this loop, which complicates post-inc
       // users.
       if (e != 1 && BB->getTerminator()->getNumSuccessors() > 1 &&
-          !isa<IndirectBrInst>(BB->getTerminator())) {
+          !isa<IndirectBrInst>(BB->getTerminator()) &&
+          !isa<CatchSwitchInst>(BB->getTerminator())) {
         BasicBlock *Parent = PN->getParent();
         Loop *PNLoop = LI.getLoopFor(Parent);
         if (!PNLoop || Parent != PNLoop->getHeader()) {
diff --git a/test/Transforms/LoopStrengthReduce/pr31627.ll b/test/Transforms/LoopStrengthReduce/pr31627.ll
new file mode 100644
index 000000000000..4bd4fc273d7b
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/pr31627.ll
@@ -0,0 +1,58 @@
+; RUN: opt -S -loop-reduce < %s | FileCheck %s
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.0.24215"
+
+define void @fn3() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  %call = invoke i32 @fn2()
+          to label %for.cond.preheader unwind label %catch.dispatch2
+
+for.cond.preheader:                               ; preds = %entry
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.cond.preheader, %for.cond
+  %b.0 = phi i32 [ %inc, %for.cond ], [ %call, %for.cond.preheader ]
+  %inc = add nsw i32 %b.0, 1
+  invoke void @fn1(i32 %inc)
+          to label %for.cond unwind label %catch.dispatch
+
+; CHECK:   %[[add:.*]] = add i32 %call, 1
+; CHECK:   br label %for.cond
+
+; CHECK: for.cond:                                         ; preds = %for.cond, %for.cond.preheader
+; CHECK:   %[[lsr_iv:.*]] = phi i32 [ %lsr.iv.next, %for.cond ], [ %[[add]], %for.cond.preheader ]
+; CHECK:   %[[lsr_iv_next:.*]] = add i32 %lsr.iv, 1
+; CHECK:   invoke void @fn1(i32 %[[lsr_iv]])
+
+
+catch.dispatch:                                   ; preds = %for.cond
+  %0 = catchswitch within none [label %catch] unwind label %catch.dispatch2
+
+catch:                                            ; preds = %catch.dispatch
+  %1 = catchpad within %0 [i8* null, i32 64, i8* null]
+  invoke void @_CxxThrowException(i8* null, i8* null) #2 [ "funclet"(token %1) ]
+          to label %unreachable unwind label %catch.dispatch2
+
+catch.dispatch2:                                  ; preds = %catch.dispatch, %catch, %entry
+  %a.0 = phi i32 [ undef, %entry ], [ %call, %catch ], [ %call, %catch.dispatch ]
+  %2 = catchswitch within none [label %catch3] unwind to caller
+
+catch3:                                           ; preds = %catch.dispatch2
+  %3 = catchpad within %2 [i8* null, i32 64, i8* null]
+  call void @fn1(i32 %a.0) [ "funclet"(token %3) ]
+  catchret from %3 to label %try.cont4
+
+try.cont4:                                        ; preds = %catch3
+  ret void
+
+unreachable:                                      ; preds = %catch
+  unreachable
+}
+
+declare i32 @fn2()
+
+declare i32 @__CxxFrameHandler3(...)
+
+declare void @fn1(i32)
+
+declare void @_CxxThrowException(i8*, i8*)