[LoopStrengthReduce] Don't increment iterator past the end of the BB

We tried to move the insertion point beyond instructions like landingpad
and cleanuppad.
However, we *also* tried to move past catchpad.  This is problematic
because catchpad is also a terminator.

This fixes PR25541.

llvm-svn: 253238

1 files changed, 51 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopStrengthReduce/pr25541.ll b/llvm/test/Transforms/LoopStrengthReduce/pr25541.ll
new file mode 100644
index 00000000000..fa64875d9af
--- /dev/null
+++ b/llvm/test/Transforms/LoopStrengthReduce/pr25541.ll
@@ -0,0 +1,51 @@
+; 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-msvc"
+
+define void @f() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  br label %for.cond.i
+
+for.cond.i:                                       ; preds = %for.inc.i, %entry
+  %_First.addr.0.i = phi i32* [ null, %entry ], [ %incdec.ptr.i, %for.inc.i ]
+  invoke void @g()
+          to label %for.inc.i unwind label %catch.dispatch.i
+
+catch.dispatch.i:                                 ; preds = %for.cond.i
+  %0 = catchpad [i8* null, i32 64, i8* null]
+          to label %for.cond.1.preheader.i unwind label %catchendblock.i
+
+for.cond.1.preheader.i:                           ; preds = %catch.dispatch.i
+  %cmp.i = icmp eq i32* %_First.addr.0.i, null
+  br label %for.cond.1.i
+
+for.cond.1.i:                                     ; preds = %for.body.i, %for.cond.1.preheader.i
+  br i1 %cmp.i, label %for.end.i, label %for.body.i
+
+for.body.i:                                       ; preds = %for.cond.1.i
+  invoke void @g()
+          to label %for.cond.1.i unwind label %catchendblock.i
+
+catchendblock.i:                                  ; preds = %for.body.i, %catch.dispatch.i
+  catchendpad unwind to caller
+
+for.inc.i:                                        ; preds = %for.cond.i
+  %incdec.ptr.i = getelementptr inbounds i32, i32* %_First.addr.0.i, i64 1
+  br label %for.cond.i
+
+for.end.i:                                        ; preds = %for.cond.1.i
+  catchret %0 to label %leave
+
+leave:                                            ; preds = %for.end.i
+  ret void
+}
+
+; CHECK-LABEL: define void @f(
+; CHECK: %[[PHI:.*]]  = phi i64 [ %[[IV_NEXT:.*]], {{.*}} ], [ 0, {{.*}} ]
+; CHECK: %[[ITOP:.*]] = inttoptr i64 %[[PHI]] to i32*
+; CHECK: %[[CMP:.*]]  = icmp eq i32* %[[ITOP]], null
+; CHECK: %[[IV_NEXT]] = add i64 %[[PHI]], -4
+
+declare void @g()
+
+declare i32 @__CxxFrameHandler3(...)