enhance vmcore to know that udiv's can be exact, and add a trivial
instcombine xform to exercise this.

Nothing forms exact udivs yet though.  This is progress on PR8862



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124992 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Assembler/flags.ll b/test/Assembler/flags.ll
index 3241909..82b35b5 100644
--- a/test/Assembler/flags.ll
+++ b/test/Assembler/flags.ll
@@ -104,6 +104,19 @@
 	ret i64 %z
 }
 
+define i64 @udiv_exact(i64 %x, i64 %y) {
+; CHECK: %z = udiv exact i64 %x, %y
+	%z = udiv exact i64 %x, %y
+	ret i64 %z
+}
+
+define i64 @udiv_plain(i64 %x, i64 %y) {
+; CHECK: %z = udiv i64 %x, %y
+	%z = udiv i64 %x, %y
+	ret i64 %z
+}
+
+
 define i64* @gep_nw(i64* %p, i64 %x) {
 ; CHECK: %z = getelementptr inbounds i64* %p, i64 %x
 	%z = getelementptr inbounds i64* %p, i64 %x
@@ -136,6 +149,11 @@
 	ret i64 sdiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
 }
 
+define i64 @udiv_exact_ce() {
+; CHECK: ret i64 udiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
+	ret i64 udiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
+}
+
 define i64* @gep_nw_ce() {
 ; CHECK: ret i64* getelementptr inbounds (i64* @addr, i64 171)
         ret i64* getelementptr inbounds (i64* @addr, i64 171)
@@ -210,3 +228,4 @@
 ; CHECK: ret i64 mul nuw (i64 ptrtoint (i64* @addr to i64), i64 91)
 	ret i64 mul nuw (i64 ptrtoint (i64* @addr to i64), i64 91)
 }
+