From 5ffdc56f53eb2cf22daa6d764a8a0fa9f94e440a Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Mon, 3 Dec 2007 19:17:21 +0000
Subject: [PATCH] If ExitValue operand is also defined in Loop header then
 insert new ExitValue after this operand definition.

This fixes PR1828.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44539 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopIndexSplit.cpp      | 17 +++++++
 .../LoopIndexSplit/Crash-2007-12-03.ll        | 44 +++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 test/Transforms/LoopIndexSplit/Crash-2007-12-03.ll

diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 5064063f29a..138e50d8a1a 100644
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -1330,6 +1330,23 @@ void LoopIndexSplit::calculateLoopBounds(SplitInfo &SD) {
   //      A_ExitValue = min(SplitValue, OrignalLoopExitValue)
   //      B_StartValue = max(SplitValue, OriginalLoopStartValue)
   Instruction *InsertPt = L->getHeader()->getFirstNonPHI();
+
+  // If ExitValue operand is also defined in Loop header then
+  // insert new ExitValue after this operand definition.
+  if (Instruction *EVN = 
+      dyn_cast<Instruction>(ExitCondition->getOperand(ExitValueNum))) {
+    if (!isa<PHINode>(EVN))
+      if (InsertPt->getParent() == EVN->getParent()) {
+        BasicBlock::iterator LHBI = L->getHeader()->begin();
+        BasicBlock::iterator LHBE = L->getHeader()->end();  
+        for(;LHBI != LHBE; ++LHBI) {
+          Instruction *I = LHBI;
+          if (I == EVN) 
+            break;
+        }
+        InsertPt = ++LHBI;
+      }
+  }
   Value *C1 = new ICmpInst(Sign ?
                            ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
                            AEV,
diff --git a/test/Transforms/LoopIndexSplit/Crash-2007-12-03.ll b/test/Transforms/LoopIndexSplit/Crash-2007-12-03.ll
new file mode 100644
index 00000000000..4b2cffd7986
--- /dev/null
+++ b/test/Transforms/LoopIndexSplit/Crash-2007-12-03.ll
@@ -0,0 +1,44 @@
+; RUN: llvm-as < %s | opt -loop-index-split -disable-output 
+; PR1828.bc
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i686-pc-linux-gnu"
+	%RPyOpaque_RuntimeTypeInfo = type opaque*
+	%arraytype_Char_1 = type { i32, [0 x i8] }
+	%arraytype_Signed = type { i32, [0 x i32] }
+	%functiontype_11 = type %structtype_object* ()
+	%functiontype_360 = type %structtype_rpy_string* (%structtype_pypy.rlib.rbigint.rbigint*, %structtype_rpy_string*, %structtype_rpy_string*, %structtype_rpy_string*)
+	%structtype_list_18 = type { i32, %arraytype_Signed* }
+	%structtype_object = type { %structtype_object_vtable* }
+	%structtype_object_vtable = type { i32, i32, %RPyOpaque_RuntimeTypeInfo*, %arraytype_Char_1*, %functiontype_11* }
+	%structtype_pypy.rlib.rbigint.rbigint = type { %structtype_object, %structtype_list_18*, i32 }
+	%structtype_rpy_string = type { i32, %arraytype_Char_1 }
+
+define fastcc %structtype_rpy_string* @pypy__format(%structtype_pypy.rlib.rbigint.rbigint* %a_1, %structtype_rpy_string* %digits_0, %structtype_rpy_string* %prefix_3, %structtype_rpy_string* %suffix_0) {
+block0:
+	br i1 false, label %block67, label %block13
+
+block13:		; preds = %block0
+	ret %structtype_rpy_string* null
+
+block31:		; preds = %block67, %block44
+	ret %structtype_rpy_string* null
+
+block42:		; preds = %block67, %block44
+	%j_167.reg2mem.0 = phi i32 [ %v63822, %block44 ], [ 0, %block67 ]		; <i32> [#uses=1]
+	%v63822 = add i32 %j_167.reg2mem.0, -1		; <i32> [#uses=3]
+	%v63823 = icmp slt i32 %v63822, 0		; <i1> [#uses=1]
+	br i1 %v63823, label %block46, label %block43
+
+block43:		; preds = %block42
+	br label %block44
+
+block44:		; preds = %block46, %block43
+	%v6377959 = icmp sgt i32 %v63822, 0		; <i1> [#uses=1]
+	br i1 %v6377959, label %block42, label %block31
+
+block46:		; preds = %block42
+	br label %block44
+
+block67:		; preds = %block0
+	br i1 false, label %block42, label %block31
+}
-- 
2.34.1