Fix pr3571: If stride is a value defined by an instruction, make sure it dominates the loop preheader. When IV users are strength reduced, the stride is inserted into the preheader. It could create a use before def situation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64579 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 27 insertions, 0 deletions

diff --git a/test/Transforms/LoopStrengthReduce/pr3571.ll b/test/Transforms/LoopStrengthReduce/pr3571.ll
new file mode 100644
index 0000000..79fcdb1
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/pr3571.ll
@@ -0,0 +1,27 @@
+; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis
+; PR3571
+
+target triple = "i386-mingw32"
+define void @_ZNK18qdesigner_internal10TreeWidget12drawBranchesEP8QPainterRK5QRectRK11QModelIndex() nounwind {
+entry:
+	br label %_ZNK11QModelIndex7isValidEv.exit.i
+
+bb.i:		; preds = %_ZNK11QModelIndex7isValidEv.exit.i
+	%indvar.next = add i32 %result.0.i, 1		; <i32> [#uses=1]
+	br label %_ZNK11QModelIndex7isValidEv.exit.i
+
+_ZNK11QModelIndex7isValidEv.exit.i:		; preds = %bb.i, %entry
+	%result.0.i = phi i32 [ 0, %entry ], [ %indvar.next, %bb.i ]		; <i32> [#uses=2]
+	%0 = load i32** null, align 4		; <%struct.QAbstractItemDelegate*> [#uses=0]
+	br i1 false, label %_ZN18qdesigner_internalL5levelEP18QAbstractItemModelRK11QModelIndex.exit, label %bb.i
+
+_ZN18qdesigner_internalL5levelEP18QAbstractItemModelRK11QModelIndex.exit:		; preds = %_ZNK11QModelIndex7isValidEv.exit.i
+	%1 = call i32 @_ZNK9QTreeView11indentationEv(i32* null) nounwind		; <i32> [#uses=1]
+	%2 = mul i32 %1, %result.0.i		; <i32> [#uses=1]
+	%3 = add i32 %2, -2		; <i32> [#uses=1]
+	%4 = add i32 %3, 0		; <i32> [#uses=1]
+	store i32 %4, i32* null, align 8
+	unreachable
+}
+
+declare i32 @_ZNK9QTreeView11indentationEv(i32*)