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/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index adcad74..a744d83 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1090,8 +1090,9 @@
               Flags |= OverflowingBinaryOperator::NoSignedWrap;
             if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
               Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
-          } else if (Opc == Instruction::SDiv) {
-            if (Record[3] & (1 << bitc::SDIV_EXACT))
+          } else if (Opc == Instruction::SDiv ||
+                     Opc == Instruction::UDiv) {
+            if (Record[3] & (1 << bitc::PEO_EXACT))
               Flags |= SDivOperator::IsExact;
           }
         }
@@ -1905,8 +1906,9 @@
             cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
           if (Record[OpNum] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
             cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
-        } else if (Opc == Instruction::SDiv) {
-          if (Record[OpNum] & (1 << bitc::SDIV_EXACT))
+        } else if (Opc == Instruction::SDiv ||
+                   Opc == Instruction::UDiv) {
+          if (Record[OpNum] & (1 << bitc::PEO_EXACT))
             cast<BinaryOperator>(I)->setIsExact(true);
         }
       }